# silver solder?



## Aydelott

I have made my crank in 3 pieces I was going to silver solder it but I got oil on it an my instructor said in his experience if you get oil on it the silver solder wont stick ive tried red lock tight an epoxy nether will hold is there some type of acid or something that can get the oil off? My boss just tought me to braze with brass rod will that hold. Please help IM so close to having this thing done I have about 650 hours in it I think I took on a little more then I could handle for my first engine thanks


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## hacklordsniper

I use alcohol or acetone for degreasing


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## Aydelott

does any one know what type of silver solder an flux i should get


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## rkepler

Aydelott said:


> does any one know what type of silver solder an flux i should get



For general use with brass, bronze and steel I tend to use 'white' flux such as McMaster # 7693A1.  Clean things with acetone or any other clean distillate (not something from the degreaser tank) then wipe with clean alcohol (denatured, not "rubbing" alcohol that will have something in it).  Put the flux on everything that you want wet, even it it's going to be touching something else with flux.  Put it together, wipe off the excess flux and get ready to braze things.

There are multiple silver brazes available with different capabilities.  For occasional home use I'd suggest a braze with cadmium - it wets and flows better.  It's not a good choice for someone using it every day, but once in a while won't build up cad lavels in your body.  Then you want to compare tight joint vs. fill - the latter will leave a fillet around a joint, the former won't.  The latter won't go into a .002" gap, the former will.  I choose each based on the joint type.  (I just looked at the prices, you might be best served by scrounging some...)  I cut small bits of wire and place it on the joint, when heating I use a little wire to push it back on when the flux boils and moves it.

Finally in my experience the think you need most in silver brazing is heat.  Not high temperatures but a lot of heat.  Weed burner heat on big assemblies (like 4" and bigger).  The faster you get things to the soldering point the better the flux will work - cook it long enough and the flux will burn out.  I like to get the silver solder melting into the joint in a couple of minutes max.  If you can try surrounding the part with firebrick on most all sides to contain the heat.


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## kvom

Everyone I know around here prefers the black brazing flux over the white.  Brake cleaner is also good for degreasing.


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## GWRdriver

Aydelott,
I'm surprised your instructor didn't go instantly to the next logical step (or remedy) . .  just clean the oil off!   I don't know what kind or size engine you are building but if it's a model (as opposed to a full size engine) Loctite will do perfectly well for both steam and IC.  It will be important for success for the journal/shaft fit clearances to be held close to Loctite specs, the joints need to be kept very clean, and then I typically pin the journals (see the photo.)  This has resulted in 100% success for small crankshafts.  I'm not saying don't silver solder it, this is just the way I do it and I'm happy with the results.  The only thing I would change about the crankshaft in the photo (a Stuart D-10) is for purely aesthetic reasons I would use steel pins next time rather than brass.  (Horrible photo color, something went wonky with the photo editor enhancements.)

Here's another thought to consider . . . in model practice, where only a few thou' of excessive clearance can make the difference between a close and a true-running fit and a loose wobbly fit (in a shaft and wheel for instance), Loctite presents us with a small conundrum.   Shall we adhere to their clearance recommendations (maybe 3 to 4 thou' on a small shaft) and create a fit that could easily set up misaligned, or reduce the curing clearance and reduce the potential for wobble but also reduce the effectiveness of the Loctite?

What I do in situations like that is to first turn my shaft (or wheel seat) to a tight sliding fit, almost a light press fit, in the wheel (or crank, etc) and then I come back and turn a shallow groove or channel almost the full width of the shaft seat to the optimal clearance recommended depth for the Loctite.  This creates a narrow shoulder on the inboard end of the seat and a kind of locater ring on the outboard end.  The channel is filled with Loctite and the wheel pressed on and the shoulder and ring serve to exactly center and align the wheel or crank on the shaft while the Loctite cures.   I have had 100% success with this technique (ie runouts at or below .001") so far as alignment goes, but I still pin cranks.


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## rkepler

Like Harry I tend to glue and pin cranks when circumstances permit - here's a shot of the layup of the crankshaft for my 3 cylinder Shay on the surface plate:






The shaft went straight through and was supported by the bearings in the crankcase, this gave me the positions for the journals and the captive eccentrics (not in this picture).  It also let me set the proper angles for the throws.  I centered things by using an automatic center punch to peen small dings all around the shaft - using the automatic punch tends to keep the sizes of the peens the same so that the shaft centers with a light press but retains enough gap around for the Loctite.  After gluing up I put taper pins through every joint (and even put loctite in them "just in case" after some internal depate on glue joint thickness and such) and remove the spare shaft in the journal.  It seems to have worked as the Shay has run 120+ miles and is just broken in (I may need to tighten up the eccentrics and reset the valve timing this winter).

And I forgot to mention using brake cleaner as a degreaser - shame on me.  I'm still hoarding my remaining stock of 1,1,1 trichlor degreaser and tend to not think of it except for extreme cleaning needs (as in gluing up crankshafts).  I should buy a case of the replacement so I could return to spraying brake cleaner with abandon.


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## Aydelott

thanks for all the info he did try to clean the oil off and even burn it off he said nothing worked but i have just got some jb weld i think im going to try that next its cheaper then silver solder an flux anyone ever tryied that???


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## MachineTom

Each material you deal with in life has a useful  purpose range. Having used JB weld with success in engine crankcase holes, sealing cracks in transmission housing, JB did the job. I believe that it is beyond its range to try in holding together a crankshaft. You have not said in what manner it will be applied, it has no capilary action, so just smear it on the journal and press it together? 

With 650 hours invested in your work, I won't want to make a cheap mistake in this regards.


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## skyline1

If your "Instructor" tried to burn it off that may be your problem he probably did just the opposite and baked it on, I use just such a process for oil "blacking" components. It actually bonds to the surface and the only way to get it off is to physically abrade it off with crocus paper or fine wire wool.

I do it with boiler casings and it won't come off no matter how hot it gets. like this




The silver solder I use is Johnson Mathey Easy Flo and Easy Flo flux but it's cadmium bearing and so is getting hard to obtain. I doubt the odd bit of silver soldering will fill your body with cadmium it's health and safety gone mad if you ask me.

They are a pretty world wide company so you should be able to get it in the States the flux is an active fluoride flux which you mix to a thick paste and apply to the joint after cleaning it well.denatured Alcohol or industrial Methanol is ideal as well as a good mechanical scrubbing with wire wool or emery paper.

Regards Mark


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## Aydelott

if you look close it his picture the crank is three parts the center an two journals in the middle being one part an the out sides with the lobe being the other they fit into a .200 pocket the same od with a .300 hole all the way threw so the lip on that pocket would be takeing most of the pressure its not going to be just jb weld holding it, an the jb says it is good to 2425 psi what do you think i cant get a better picture to really see it till tuesday the rod the crank arm spins on is part of the outside so its only needs to be fixed on the side with the hole


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## goldstar31

OK, this is my first posting here but it time to debunk a lot of old wives' tales.
The first thing is to get it clean. Forget the so called expert who suggests some liquid cleaner as this only dilutes the contamination. 
You have to get it rubbed clean with something like steel wool and then prepare your powder flux mixed to a paste with a drop of household washing up liquid.
If you are any great shakes and you are doing something like a model locomotive boiler, you might have to pickle it clean with dilute sulphuric acid. |No, don't think about stuff from a car battery.  I've known people who  used things like vinegar bodied sauces. British HP sauce is great!
Back to ordinary silver soldering and if you want, use a scraper end to remove whatever muck there is. Again, you can use silver solder paint which is fine silver dust with an acid to etch the work. So you are back to sulphuric or hydrochloric or acetic acids. Frankly,, I like solder pastes and once they are hot enough- that is little globules of molten silver, you wipe it clean with a dry paper towel or tissue. This leaves a 'tinned' surface ready for proper soldering.
Again, your rod should be clean and warmed a little enough to dip in dry flux. so that the flux sticks ready for the joint.
If you read this carefully, you will find that all that I have written is concerned with cleanliness at all stages.

I hope that the foregoing is useful.


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## digiex-chris

another problem with burning off the oil is the heat. Heat without a barrier to oxygen like flux increases the rate of oxidization. If any color change took place from the heat, you've got a layer of oxidization. Solder of any kind won't stick to oxidization. I definitely think it's inaccurate saying that once oil comes in contact with your part you won't be able to silver solder it, since many of us use a cutting oil to manufacture these parts. 

Clean well, brake cleaner is fantastic for that. Rub off any oxidization that may have formed while you messed with it (any discolouration of any kind) with steel wool or something. Don't touch it with even your fingers or you've gotta degrease again! 

Practice on something that's not your final part.


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## skyline1

Goldstar31

I agree with you 100% cleanliness is indeed next to godliness with silver soldering and mechanical abrasion and elbow grease is the best way to achieve it along with a good active flux and an acid pickle for copper. You do silver soldering just the same way I do.

Regards Mark


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## rkepler

goldstar31 said:


> OK, this is my first posting here but it time to debunk a lot of old wives' tales.
> The first thing is to get it clean. Forget the so called expert who suggests some liquid cleaner as this only dilutes the contamination.
> You have to get it rubbed clean with something like steel wool and then prepare your powder flux mixed to a paste with a drop of household washing up liquid.



Steel wool will introduce oil to whatever you rub it on, and "washing up liquid" (dish washing liquid in the states) is mostly surfactants that will have an unknown effect on the flux action.  If the point is to have clean metal at the joint I'd suggest that both of these activities would be counterproductive.



> If you are any great shakes and you are doing something like a model locomotive boiler, you might have to pickle it clean with dilute sulphuric acid. |No, don't think about stuff from a car battery.  I've known people who  used things like vinegar bodied sauces. British HP sauce is great!


HP sauce is OK on fries, but I'm not sure that I'd use it on a boiler - the copper would make it taste funny.

But "Sparex" is an acceptable substitute to all of those, and if you're cheap like me you can just go to a pool/spa supply and pick up some sodium/potassium bisulphate and use it at the rate of 1 lb/gallon (handy since a 5 lb supply works in a 5 gallon pail).  I tend to cool work in the pickle, that tends to blow scale off the copper.  It also plates some copper back onto steel (requiring some cleaning) and can splash some acid around - I've lost several pairs of jeans that way.



> Back to ordinary silver soldering and if you want, use a scraper end to remove whatever muck there is. Again, you can use silver solder paint which is fine silver dust with an acid to etch the work.


Most of the silver braze acid fluxes I've seen are boric acid based, I've never used it in modeling, it's much more common here for use on silver (lots of jewelry making around here).  All the silver brazing fluxes that I know of for copper contain borax and usually some fluorides to remove oxides and keep them off during the brazing process.

But your point is taken - you need clean surfaces to braze, and you need flux that stays in place when the joint is being heated.  I'll add that you need enough heat to get the joint hot enough for the braze to melt and fill the joint before the flux burns off.  When you have all of those things in place the braze flows into place like magic, a neat process to watch.


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## davedfsme

Brake cleaner comes in a spray can.  Not only does it dilute oil and dirt, but it physically blows it off your parts.  That doesn't mean that it is CLEAN after using copious amounts (it leaves a white residue) but all oil is GONE if you are thorough. Follow with compressed air to get rid of the contaminated solvent faster than it can evaporate, which would re-deposit residual contaminants.  Use it as a first step to cleaning, it makes the physical part of mechanical cleaning a lot easier if you are not smearing "grease" around on your parts.  Wash your steel wool, "Scotchbrite" or other abrasive with brake cleaner (or alcohol) to remove any residual oils or other contaminants from the abrasive, and rub off the oxides and dry contaminants on the surfaces before fluxing.  (Most commercial steel wool is treated with a very light "drying" oil to resist oxidation during storage)  Pay more attention to "IDs" of finished parts than "ODs", simply because they are harder to clean.  Flux all mating surfaces completely (as mentioned before) before assembly.  Use a commercial flux to suit the brazing alloy and materials you are using.

  "Yo' Mama" might have told you that "Cleanliness is next to Godliness".  Underarms might smell a little in the shop without affecting anything, but if you want success with  any type of brazing for critical applications . . .  surgical cleanliness is your goal.  The job of the flux is to protect the surfaces from oxidation during heating AND to remove what you might have missed, in that order.  Asking it to chemically clean the parts that "you didn't bother to" is a recipe for failure.

  The same goes for adhesive methods, except now you don't have flux to help bubble out any missed crap.  Glue bonds are only as good as the surface they are trying to stick to.  If it ain't clean, it won't stick!

  IMHO, JB Weld is best for replacing missing (or worn away) material.  Asking it to reliably provide a shear strength in a "thin film application" is asking for trouble, especially if your surfaces are covered in crud.  For critical clearance applications like a crankshaft, you would have better luck with Loctite, if your parts are clean.  Recommended clearance issues can be dealt with by progressive fits as suggested above, and/or by "zero-stress" assemblies, relying on position during cure to allow the parts to locate themselves by fluid dynamics (surface tension???) to insure concentricity and alignment of  pins and bores.  Low viscosity, high strength adhesives, correctly applied, will logically give better results than the other way around.

DJD


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## goldstar31

Actually a professional would read some of the replies with some misgiving. I tried to simplify my reply so that the beginner would have success.
Whether this was done, I have yet to be informed. Instead, I got a number of contradictions and tangents away from the original issue.

Actually, the point was missed about oil and cleaning with brake cleaner and alcohol. I spent four years after retirement doing a City and Guilds in Motor Vehicle Restoration and despite the fact that this was somewhere where brakecleaner  should have been a common thing, we never had any! So much for such advice.
Again, oil is virtually impossible to remove from cast iron. Cast iron is actually porous. Back to the drawing board!

In the 1950's, after the Goldstar bit in my life, I was involved in 'tinplate or ternplate' and it was delivered by the thousands of tons( tonnes) and it was oiled.
That stuff became the raw material for both the soldered can bodies and the ends. It went through the solder horses and was sealed with lead solder.

So back to this Happy Retirement away from demands of a real job and we had to learn 'leading' which is filling and filing panels  with lead prior to painting.
What was the lubricant? Well, the book says either vegetable oil or traditional tallow.  In fact tallow is the 'flux' for lead piping. 

So where have most of you gone wrong? You have to do a bit of chemistry and learn or re-learn about heat and fatty acids. If you take oils up to a high heat and the oil changes from a lubricant etc to an oil which is a drying oil and which will oxidise into a varnish or medium for oil based paints.

If taken further, it will change yet again- and taken further up the heat range it will probably fall off!

I DID try to simplify even this reply. Unfortunately,  one  walks away from the opportunity to pass on  further free advice.

Good Morning!


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## pete

DJD,
SPRAY TYPE BRAKE CLEANERS? Are you completely serious? Ever hear of that Phosgene gas used in the trenches during the first world war that was meant to actually KILL? Add heat to the right spray on brake cleaner and that's what you get. EVERYBODY should know that by now since it's been well documented and common knowledge for years. I know more than a few welders that would do their very best to get anyone fired that used it prior to them welding on anything. I'm about as far from a safety freak as you can get, but I can't believe you would advise using brake cleaner prior to heating anything.

Pete


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## davedfsme

Goldstar,

  I was not trying to imply that you were wrong in any way.  I was merely suggesting that a person could make the job easier on themselves by getting rid of as much oil and crud as they can BEFORE mechanically cleaning their parts.  It is still necessary to abrade the surfaces, pickle is an excellent plan, active flux for the materials used, heat range and time spent at heat needs to be selected and utilized.

  Please keep in mind that lead based SOLDER is entirely different than silver BRAZING.  Temperatures used for soldering don't burn the petroluem/acid solder pastes or the "killed" fluxes, if properly applied.  The presence of lead solder WILL destroy the wetting ability of the best grade "silver solder", which in itself is an antique misnomer.  The only "solder" which should be considered as "silver" is the "high-melt" lead solder which contains ~2% silver.  The rest of this discussion has been concerned with "Easy-Flo", "Argo-bond" etc.  I am not about to wipe a joint which is at a red heat!

  It's that whole bit about the oil oxidizing at heat which has me stymied . . .  We are desperately trying to exclude oxygen from the surface to prevent the metals from oxidizing.  (Prime purpose of the flux . . . remove residual oxidization, and prevent any further oxidization from occurring.)  Brazing fluxes are water or alcohol based, typically containing flouride or boric acid compounds . . .
solder paste is zinc chloride, if I remember correctly?


  I think we are referring to different processes, using different materials, at different temperatures.

DJD


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## davedfsme

pete said:


> DJD,
> SPRAY TYPE BRAKE CLEANERS? Are you completely serious? Ever hear of that Phosgene gas used in the trenches during the first world war that was meant to actually KILL? Add heat to the right spray on brake cleaner and that's what you get. EVERYBODY should know that by now since it's been well documented and common knowledge for years. I know more than a few welders that would do their very best to get anyone fired that used it prior to them welding on anything. I'm about as far from a safety freak as you can get, but I can't believe you would advise using brake cleaner prior to heating anything.
> 
> Pete


Pete,

  Yup.  I am completely serious.  Only as a pre-treatment, to remove oil-based crud, followed by scrubbing to remove oxides and brake wash residues.

  Who said anything about cast iron?

  Anyone who applies heat to volatile compounds is asking for any manner of combustible troubles.  As a pre-treat, the majority of the materials used for cleaning the parts will have evaporated long before any serious heat is applied.  We weren't talking about welding "wet" components here.  You still need to scrub the parts back to bare metal before fluxing.  You might want to consider that the fluxes used for silver brazing are in themselves often flouride compounds, and the alloys used have historically contained cadmium as a wetting agent.  This is not a "healthy" process to start with, and "adequate ventilation" is a prerequisite.

  But, you may have a point that I am not aware of.  I also smoke cigarettes, ride motorcycles, drink whiskey, eat fast food (occasionally), and am still alive.  The biggest problem I have with silver brazing is using just enough alloy to form a meniscus fillet, mine always seem to have a little run of excess somewhere or another.

Regards,

DJD


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## davedfsme

Oops . . .  the cast iron reference should have gone to "Goldstar 31".  My apologies, please consider the comment re-directed.

DJD


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## davedfsme

Skyline 1,

  I have to apologize . . . you used the exact same "cleanliness is next to Godliness" that I attributed to "Yo' Mama".  My mama had the same to say, but to the best of my knowledge, she never did any silver brazing . . .

DJD


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## pete

davedfsme said:


> Pete,
> 
> Yup.  I am completely serious.  Only as a pre-treatment, to remove oil-based crud, followed by scrubbing to remove oxides and brake wash residues.
> 
> Who said anything about cast iron?
> 
> Anyone who applies heat to volatile compounds is asking for any manner of combustible troubles.  As a pre-treat, the majority of the materials used for cleaning the parts will have evaporated long before any serious heat is applied.  We weren't talking about welding "wet" components here.  You still need to scrub the parts back to bare metal before fluxing.  You might want to consider that the fluxes used for silver brazing are in themselves often flouride compounds, and the alloys used have historically contained cadmium as a wetting agent.  This is not a "healthy" process to start with, and "adequate ventilation" is a prerequisite.
> 
> But, you may have a point that I am not aware of.  I also smoke cigarettes, ride motorcycles, drink whiskey, eat fast food (occasionally), and am still alive.  The biggest problem I have with silver brazing is using just enough alloy to form a meniscus fillet, mine always seem to have a little run of excess somewhere or another.
> 
> Regards,
> 
> DJD



DJD,
I'm more than well aware of the need for good ventilation while silver soldering. I've worked with, am rated for, and have used the Scott self contained air packs in more than a few industrial enviroments. I also drink, smoked up till my first heart attack, speed at times, and have hauled and used high explosives many times. I've spent my whole working life doing some very dangerous jobs. But I knew enough and had the correct training to take most of those calculated risks. I've sat through hundreds of industrial safety films, and a couple about this product. For now I'm still alive too despite more than a few fools trying to change that status.

There's many many new members here that don't come from that back round and don't know enough, or may not even know about the online MSDS data sheets to double check some of the thankfully rare misinformed and uneducated crap that gets posted on forums like this. Do the research, even a few missed or unnoticed drops of that brake fluid can and will kill you. To knowingly post a reccomendation of it's use without any warning at all is more than inexcuseable. Especially so when there's far safer and easier to use products that will do the exact same job better. This is a hobby for me, It's SUPPOSED to be enjoyable. Having to make posts like this isn't.

Pete


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## skyline1

davedfsme said:


> Skyline 1,
> 
> I have to apologize . . . you used the exact same "cleanliness is next to Godliness" that I attributed to "Yo' Mama".  My mama had the same to say, but to the best of my knowledge, she never did any silver brazing . . .
> 
> DJD



No apology required mate it's a point that should be repeated. It's a golden rule with silver soldering (or soft soldering for that matter) "get it clean, scrupulously clean"

Actually my mum did do a bit of silver soldering or at least assisted my dad and I with it.

Whilst on the subject those plastic fibre cleaning mats used for washing up are quite good for cleaning components prior to silver soldering. When mum had one go missing she usually knew who had pinched it.

Also very useful are the abrasive blocks used for cleaning Printed Circuit Boards prior to soldering electronic components in. Indeed they are designed for just this job.

Regards Mark


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## davedfsme

pete said:


> DJD,
> I'm more than well aware of the need for good ventilation while silver soldering. I've worked with, am rated for, and have used the Scott self contained air packs in more than a few industrial enviroments. I also drink, smoked up till my first heart attack, speed at times, and have hauled and used high explosives many times. I've spent my whole working life doing some very dangerous jobs. But I knew enough and had the correct training to take most of those calculated risks. I've sat through hundreds of industrial safety films, and a couple about this product. For now I'm still alive too despite more than a few fools trying to change that status.
> 
> There's many many new members here that don't come from that back round and don't know enough, or may not even know about the online MSDS data sheets to double check some of the thankfully rare misinformed and uneducated crap that gets posted on forums like this. Do the research, even a few missed or unnoticed drops of that brake fluid can and will kill you. To knowingly post a reccomendation of it's use without any warning at all is more than inexcuseable. Especially so when there's far safer and easier to use products that will do the exact same job better. This is a hobby for me, It's SUPPOSED to be enjoyable. Having to make posts like this isn't.
> 
> Pete


Pete,

  OK, fair enough.  I strongly agree that you make a very valid point about educating oneself about the materials you intend to use.  That is only common sense, which unfortunately, is becoming less common . . .

  I googled "Phosgene", and I see exactly why you are so concerned.  Anyone else curious?  http://en.wikipedia.org/wiki/Phosgene 

  I should have been more specific than "brake cleaner".  I remember the stuff I think you are referring to, the stuff with 1,1,1 tri-chlorethylene?  These days, at least around here, I wouldn't know where to find it anymore.  The stuff I use is "Non-chlorinated brake parts cleaner", 60-100% Heptane (n-heptane) according to it's MSDS.  Extremely flammable, creates a flash fire hazard as it evaporates.  Still not a "safe" material to have around sources of ignition, causes organ damage if inhaled etc.  No hazardous phosgene decomp products are formed, as there is no chlorine in it.

  Now, if somebody found a rusty old spray bomb while cleaning out Grandpa's garage, they really ought to figure out what's in it before using it for anything.  A lot of hazardous chemicals were on the market in the "good ol' days" that have been completely pulled from the market due to environmental and health concerns.  Different countries have different regulations as well.  In some places, you may be commonly able to buy stuff that is completely restricted elsewhere.

DJD


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## davedfsme

skyline1 said:


> No apology required mate it's a point that should be repeated. It's a golden rule with silver soldering (or soft soldering for that matter) "get it clean, scrupulously clean"
> 
> Actually my mum did do a bit of silver soldering or at least assisted my dad and I with it.
> 
> Whilst on the subject those plastic fibre cleaning mats used for washing up are quite good for cleaning components prior to silver soldering. When mum had one go missing she usually knew who had pinched it.
> 
> Also very useful are the abrasive blocks used for cleaning Printed Circuit Boards prior to soldering electronic components in. Indeed they are designed for just this job.
> 
> Regards Mark


Mark,

  I know the scrub pads you are referring to, but the cheap domestic ones from the supermarket have an industrial counterpart which are far better, IMHO.

  I am not sure of the rules on this forum regarding product plugging.  If this is too cryptic, PM me.

  There is a Mining and Manufacturing company in Minnesota that makes abrasive pads (and MANY other things, including Cellophane tape used for packaging).
  These pads would make a Scotsman brighten up when he sees how well they work.

  There are a variety of different grades, color-coded to indicate grit sizes.  White is the finest, then light grey, maroon, dark grey as about as coarse as you want for hand work.  If you only want one to try, I'd suggest that the maroon ones are a pretty good all-purpose grade.

  I have no financial interest in this company, I am merely a satisfied customer.

DJD


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## skyline1

DJD

I think I know the "little" outfit you are talking about. As a sound engineer at one time I should do. Used plenty of their product in recording studios, miles of it in fact.

They make those PCB cleaning blocks too I believe. I'm another satisfied customer good gear.

Regards Mark


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## goldstar31

There is a bit of 'wandering' going on. It's all very well talking about Grandpa or Auntie Fanny's experiences or whether one pan scrub is better than that of a company who is only paying less than 3% to its shareholders.

Has the poster learned anything from all this?


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## skyline1

goldstar31 said:


> There is a bit of 'wandering' going on. It's all very well talking about Grandpa or Auntie Fanny's experiences or whether one pan scrub is better than that of a company who is only paying less than 3% to its shareholders.
> 
> Has the poster learned anything from all this?



I would hope the poster has learnt quite a lot but I don't know what a company is paying it's shareholders has to do with silver soldering.

Regards Mark


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## goldstar31

Oddly it does have a lot to do with the subject. It determines where a company is going to end up or where it is going to knock out the weak products or people or whatever.

It might determine things that will end up in China or the Far East. 

Now there's a topic to flog. 

The Goldstar is the Star of India or Pakistan as it now is.

I hope that I haven't killed too many sacred cows that might be moo-ing about


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## davedfsme

goldstar31 said:


> There is a bit of 'wandering' going on. It's all very well talking about Grandpa or Auntie Fanny's experiences or whether one pan scrub is better than that of a company who is only paying less than 3% to its shareholders.
> 
> Has the poster learned anything from all this?


Goldstar,

  OK, we all "wandered" a bit, but not "off-topic".  Methods and materials used for cleaning parts, and dangers inherent in using wrong materials . . .  risk of death is important, no?

  Let's recap, then we can carry on from here:

  Don't use use "Grandpa's" aerosol brake cleaner on parts which will be heated.  If the chlorinated solvents don't poison you, the propellant pressurizing the can might (CFCs). 

  As far as the scrub pads go, "Auntie Fanny's" pot scrubber might work OK, but the industrial pads with abrasives embedded in their matrix are far more effective.  (BTW, they would scratch the heck out of Auntie's pots.)   They might cost more per pad, but when you get more use out of them with less "elbow grease", is that not helpful information?

  Different fluxes are required for different applications.  Manufacturers know this, that is part of why you need to read up on what you are doing.

  Adequate ventilation and personal protection is important.  Fumes from this process can kill you, quickly, or slowly, depending on your choice of materials.

  In this light, the all-important message about actually using the established MSDS system was brought to the forefront yet again.  Pete was quite correct in pointing out my error in suggesting simply "brake cleaner" as a solvent, as some people may actually have access to the stuff I personally consider to be "old-school".

  Is that "wandering", or simply "covering the bases"?  When you consider the various viewpoints and the international nature of a forum such as this, I don't feel that there have been that many wasted words.  At the same time, I personally have had to clarify several of my statements.  I apologize for putting mouth in motion before putting brain in gear.

 What's next?  Anyone else have anything positive to add?

DJD


----------



## davedfsme

goldstar31 said:


> Oddly it does have a lot to do with the subject. It determines where a company is going to end up or where it is going to knock out the weak products or people or whatever.
> 
> It might determine things that will end up in China or the Far East.
> 
> Now there's a topic to flog.
> 
> The Goldstar is the Star of India or Pakistan as it now is.
> 
> I hope that I haven't killed too many sacred cows that might be moo-ing about


Who's wandering now?


----------



## goldstar31

davedfsme said:


> Who's wandering now?


Me but :-
I.  I can weld and have professional qualifications in both engineering and accountancy
2. I still have a fully equipped workshop
3. I have actually taught it- to people who left school at 14
4. I have an invitation to re-vist HongKong
5. I have the wherewithal but not in 3M 

Perhaps this isn't quite what you expected? Tough!


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## davedfsme

My turn to ramble . . .  

  My mentor, Jim Mandy, passed away in '07 (at 85) of cancer.  He started out building instrument panels for Spitfires in WWII, became an artillery Master Sergeant, was a gunsmith after the war, and worked in a university hospital as an instrument maker, where he was credited with assisting in developing several advances in radiation therapy.  This is the man who taught me to silver braze.  Jim retired in '85, and built Martin Evans' "William" as a "rookie" model engineering project. A Wallis & Steevens road roller followed, and I was assisting him on a 3" scale Foden at the time of his death.

  Jim made his own flux for silver brazing on copper, with boric acid in a brown glass bottle from the chemist, borax from the grocery store, and something (?) in a prescription jar.  This was all mixed with fondue fuel (methyl hydrate), as he had found that it gave better results than distilled water when heating from "pasty".  His flux was comparable to the H&H "Handy-Flux" (which contains potassium fluoride) when used on copper, but he insisted on commercial flux for use on steel.  I wish I knew what was in that other bottle . . . and where he got it.

  Now, Jim's methods would give the health and safety guys fits.  In a different time and place, they worked for him.  We tackled the Foden boiler with a weed-burner (Tiger-torch) and an oxy-aceytlene "rose-bud".  At this point, Jim should have been, (and sometimes was) in a wheelchair, but he was far too "ornery" to accept that he was disabled.  We didn't get the Foden boiler to pressure test stage before he died, but I did get to be "his hands" for several procedures on far larger assemblies than I have tackled on my own.  The workshop, and contents, were liquidated by the family without any notice to his friends . . . 

  Long story short, there are many ways to get a given job done.  "Grandpa's method" worked for him, but may have contributed to his death.  Educate yourself before trying anything.

DJD


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## goldstar31

I am intrigued! As far as I know, Spits were never built in Canada and I am unable to recognise the rank of Artillery Master Sergeant( plumber) and being  involved as an instrument 'basher' on Spit Panels. Unless the whole panjandrum took place outside of Canada, I doubt that there was no more than a handful of Spits in Canada. They would be in RAF hands training British pilots after they got their wings! My old neighbour did train in Canada to go onto Seafires but he was flying in action off carrier decks in Korea.
There certainly are two Spitfires in Canada now. One is a 'civvy job' now but rejoiced in the serial SL-721 with JM*R  and she was a Goldstar 'girl'  in duckegg blue and flown by Jimmy Robb and Arthur Fane De Salis- Goldstar Boss at the time- but at RAF Hendon.

You see- I was there. It's engine basher is still alive but a mere Leading Aircraftsman.Actually our Goldstars Association  got some photos of our Percival Proctors from Wings of Canada who have or had the 16E. It's a bit confused because we had a 14, a LF16E and a Mark 9- and my memory at 82 is a tad shakey.

I have no doubt however that your old mentors 'secret stuff' was an acid etch cleaner mixed with boric acid.
However, I can tell you that my wife never used anything other than borax and water and she went on to become not only a Dentist but held a Diploma in Orthodontics, RCS England as well as a Fellowship of the Royal College of Surgeons of Edinburgh.
Going back to her earlier BDS Dunelm days which were 50 years ago, she was with the author of GH Thomas's Model Engineers Workshop Manual which contains a deal of information on silver soldering. If there had been anything amiss with George's techniques, he would have changed it.
My daughter is also Doctor in Orthodontics and she doesn't seem to do other than spot weld and stick things with glue and charges enough to buy us all out


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## davedfsme

goldstar31 said:


> I am intrigued! As far as I know, Spits were never built in Canada and I am unable to recognise the rank of Artillery Master Sergeant( plumber) and being  involved as an instrument 'basher' on Spit Panels. Unless the whole panjandrum took place outside of Canada, I doubt that there was no more than a handful of Spits in Canada. They would be in RAF hands training British pilots after they got their wings! My old neighbour did train in Canada to go onto Seafires but he was flying in action off carrier decks in Korea.
> There certainly are two Spitfires in Canada now. One is a 'civvy job' now but rejoiced in the serial SL-721 with JM*R  and she was a Goldstar 'girl'  in duckegg blue and flown by Jimmy Robb and Arthur Fane De Salis- Goldstar Boss at the time- but at RAF Hendon.
> 
> You see- I was there. It's engine basher is still alive but a mere Leading Aircraftsman.Actually our Goldstars Association  got some photos of our Percival Proctors from Wings of Canada who have or had the 16E. It's a bit confused because we had a 14, a LF16E and a Mark 9- and my memory at 82 is a tad shakey.
> 
> I have no doubt however that your old mentors 'secret stuff' was an acid etch cleaner mixed with boric acid.
> However, I can tell you that my wife never used anything other than borax and water and she went on to become not only a Dentist but held a Diploma in Orthodontics, RCS England as well as a Fellowship of the Royal College of Surgeons of Edinburgh.
> Going back to her earlier BDS Dunelm days which were 50 years ago, she was with the author of GH Thomas's Model Engineers Workshop Manual which contains a deal of information on silver soldering. If there had been anything amiss with George's techniques, he would have changed it.
> My daughter is also Doctor in Orthodontics and she doesn't seem to do other than spot weld and stick things with glue and charges enough to buy us all out


Jim immigrated to Canada in '54.  His mum's house was just east of London during the war, but a buzz bomb fell short or was shot down before reaching the city.  Apparently, the kitchen table ended up in the basement.  

I have obviously screwed up in remembering his rank.  Jim was apprenticed at the works building Spitfires, but signed up for front line service.  Due to his metal-working experience, he got redirected into armament repair.  That experience led him to set up shop here in Canada as a gunsmith, as a sideline to his work at the hospital.

  If you are curious, his full name was Colin James Mandy.

But, enough about Jim.  We were speaking about silver brazing . . .


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## kf2qd

To clean oil from parts I would use a detergent like Dawn Dish detergent in hot (boiling water) and then a couple rinses in clean boiling water. All this in disassembled form. Parts will be clean from oil and will rust rather readily. If you try to clean in assembly, all you willl do is clean the outside parts and leave the inside oily.


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## digiex-chris

How much dish detergent? From my experience doing dishes, a little goes a long way in making the bubbles go everywhere. I imagine putting some in boiling water will froth like crazy!


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## goldstar31

We have gone off at another tangent. We don't need to teach our carefully machined part to swim on bath night, we only want to stick it together perhaps running a tiny fillet of solder to achieve the result. The classic way is still to pickle it- with something that will not only clean but etch it- to marginally make an alloy of the silver solder INTO the steel or brass parts.

This is where this internet thing lack of detail, pisses an old fella off. The silver solder upon melting on the metal- changes its melting point having lost the some silver as mentioned earlier.

I think that I'll leave it at that---------------------intravenous injection of strong coffee!


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## goldstar31

Coffee consumed, the leaves around the castle's portcullis are too damp to remove so I thought that I'd spend some of my loot before the family and the Government get equal halves! So I went to John Stevenson's excellent site 'Home workshop' that ads goodies but also has wise comments .
There is presently a large contribution about cleaning 'machinery' which expands my humble screed. Read it, it is good!


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## digiex-chris

Sorry, but your post also suffers from the lack of detail you speak of. What do you recommend to pickle the object with? Are there agents you buy, or do you make them? Many of us are here looking for details because we lack the experience. There are thousands of cleaning products and we need the experts to help us weed them out!


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## goldstar31

I thought that I had prattled with enough details earlier but if other will forgive repetion.
You need a flux to silver solder. For most purposes an ordinary borax one will suffice. If you are onto things like stainless, you might need a so called better one. Again, you can use a silver solder paste which has flux and etch in it. I would still borax flux on the succeding operations. However, using a simple borax flux( or proprietory powder) it is applied to a cleaned bit of metal. Cleaning the metal means cleaning it properly. If it is pretty clean, a bit of clean emery or glass paper or cloth should suffice to remove any light corrosion. If it is highly corroded or something like cast iron, it should be pickled either in an acid or a strong alkali. I like dilute sulphuric which removes casting sand as well as rust and grease. Others will say Hydrochloric or Phosphoric acids whic may be rust,drain or limescale removers in the normal life. Others will clean off with caustic soda which will also do drains and rust and if you are so inclined, get rid of your mother in law completely! Large bath, large amount of soda and large mother in law- and all down the plug hole. You can also chop her up and cook her and invite the police to a banquet but I digress. You have a squeeaky clean mother - no, couple of bits of metal! Time to flux it and the flux is made into a thick paste with water to which a bit or drop of detergent is added. The reason for the paste rather than the powder is obvious- if it is dry, the torch might blow it away before it is melted to a glassy molten state. Time to use that silver solder and time to realise that is silver and expensive. You only cut or snip what is needed. If it is a pipe, you make a ring if you have a larger job, you might have to go with a stick which is dipped in flux. Here the heat comes in. This is where you have to judge just how much heat and how little heat you need. If you are doing a tube, the little ring should melt by circling the torch to even out the heat. It should melt evenly with dross./old flux/dirt on the top of the melt. You should have something which is wicking rather than cinder toffee. Do you still have that? 
Ok, if you have been playing with a copper locomotive boiler you will not be able to do it all at one heat and the copper will have hardened. With the whole thing red hot, you mutter a prayer and dodge the splashes dunking it all into a pickle bath which will do three things. It will remove the old flux, it will soften the copper and scare the **** out of you.

My old mate's Simplex boiler, he and me had the oxy/acetylene going madly and tube after tube went in. Having a spit and a drag, the hot boiler was dropped quickly into the sulphuric pickle bath which was a porcelain sink with lead plugs.

And then he had a minor heart attack. So I had to shut off the regulators, give him nitro glycerine tablets( yea, they can go bang) and get him to hospital.

Well you did ask! The first aid course will follow after a short commercial break.


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## davedfsme

Goldstar,

  I'll gladly forgive any repetition, if you'll allow me to fill in a few details . . . 

  Acid Pickle:  I like sulphuric acid pickle too.  Cheap, easy to find (any automotive battery shop) and effective.  Minor downside is disposal once it is played out.  Do not use full strength from the chemist (or battery shop), it needs to be diluted IN water (NOT "with water"!!!  The distinction is very important!).  "Water" contains impurities, which in reacting with the concentrated acid, releases heat energy.  The last thing you want is a violent reaction in a mass of concentrated acid, erupting all over you and your surroundings!  Add the acid to the water SLOWLY, and any reaction disperses through the water.  If it starts to boil, STOP adding, and the reaction will stop too.  Probably obvious that you want to stir while adding . . .

  How much to add?  To think as a chemist, you will know the concentration of the acid you are adding, and have calculated your dilution ratio based on the final concentration desired.  Knowing the final volume of dilute solution you intend to produce, it would be a simple matter to calculate the volumes of each component required.  This would be the most correct and logical way to proceed.

  I am not a chemist, I'm a shop rat.  I want my pickle to produce a nice "salmon pink" surface on my copper parts in less than 20 minutes soak at room temperature (even less from hot), and I still want time to get my jeans off before my skin starts to bubble if I get splashed.  (If that happens, have a COLD shower immediately, wash with baking soda to neutralize the acid, soap to get rid of the salty residue, and seek medical attention if blisters pop out.)  Using commercial battery acid, I started with 10 parts water/1 part acid.  Add acid to the bath until you are happy with the results.  As the acid is depleted by reaction with the parts going through the bath, it will need to be replenished.  If you don't the reaction will slow down . . .

  The acid bath needs to be kept in a container that it won't react with . . .  this, too should be obvious.  I use a plastic bucket, but this is not ideal.  If I drop a hot component, it may melt a hole in the bucket.  Goldstar's porcelain sink with lead stoppers solves that problem, but is hard to seal for long-term storage.  A steel bucket is likely to rot through in a month . . . with poisoned pickle all over the floor.  LBSC reportedly kept his in a lead-lined wooden box, but this might be less than ideal too.

  BTW, and IMHO, heat softens copper.  Quenching just cools it faster.  Cold-work (bending) will harden it, but simple heat will soften (temper) it again as long as it is not stressed to the point of cracking..  Quenching has no effect on the ultimate hardness.  If someone has proof otherwise, I'd like to hear it.

  Anybody remember the grade school "bottle rockets" or "volcanos" using vinegar and baking soda?  That was intended to teach you that mixing even "kitchen materials" can cause violent reactions . . .

  Ask any high school chemistry student how to speed up a chemical reaction . . .  add heat.  Allow your parts to cool at least until "black" (all traces of red heat are gone, in the dark (turn the lights out)) before plunging into the bath.  You still want enough heat for thermal shock to crack loose the "glass-like" flux deposits.  Expect a violent boil!  You have the heat of quench, plus the acid reaction.  This does nasty things to the atmosphere, don't do this in an enclosed space next to your lathe.  Acid solutions should be kept in an outbuilding, tightly capped.  Fumes released will cause corrosion.  I rely on the lid seal of the bath container (in a somewhat heated space) to keep the fumes in while keeping the solution from freezing and bursting the container during the winter.

  My mentor, Jim, advocated citric acid for a pickle for "non-ferrous" parts.  Not only is the pickle less hazardous to your skin, it doesn't cause nearly the same level of corrosion due to fuming.  Citric acid is available from health food or wine-making stores, but they often look at you funny when you try to buy 2 kilos at once to make up 20 litres of bath.  IMHO, it works OK for copper-based alloys if you can let it soak long enough, but it ain't worth a $#!t for ferrous parts.

  If you opt for a sulphuric acid pickle, keep a separate bath for ferrous parts.  Iron poisons copper, and the other way around too.  In fact, you can copper plate steel parts with the spent copper pickle . . .  Someone correct me if I am wrong, but the green color and the blue precipitate in a "copper" sulphuric pickle tank is due to copper sulphate?  Was that not used as marking out fluid before Dykem Blue?  (I apologize for asking for answers at the same time as offering others, but we all learn something new everyday.)

  Regarding poisoning acid baths;  Do not use "spent" or recycled battery acid for bath material.  New stuff is OK, but used stuff is polluted (poisoned) with lead.

  Like I said, I'm just a shop rat.  Any chemical engineers ringing in might have some words of wisdom to keep this thread alive.

DJD


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## rkepler

davedfsme said:


> How much to add?  To think as a chemist, you will know the concentration of the acid you are adding, and have calculated your dilution ratio based on the final concentration desired.  Knowing the final volume of dilute solution you intend to produce, it would be a simple matter to calculate the volumes of each component required.  This would be the most correct and logical way to proceed.



The industry (at least for jewelry) doesn't use sulphuric acid but instead a compound sold as "Sparex".  You can buy Sparex but it's usually cheaper to buy sodium/potassium bisulphate more commonly known as "dry acid" at a pool or spa supply.  Mixing this about 1 pound to a gallon of water makes a decent pickle.

I mix mine in a 5 gallon plastic pail, the same one available at hardware stores with the snap on lid.  Mine usually had 4 gallons or so of solution and lives on porch outside my shop next to the clear water rinse pail and 5 gallon salt water quench pail.

When the pickle action gets a little slow I degrease some steel wool and toss it in for a while.  I try to remember to pull it in an hour or so, it'll come out with a bunch of black gook that's a lot of the copper from solution.  If that doesn't clear the blue/green color I do it again.  It's not necessary unless you're using the pickle a lot.

The acid in the pickle will blow a hole in your jeans at the next wash, but won't eat up skin (maybe if you held it under for a while) - i.e. I've reached in to grab stuff I couldn't hook with a wire.  It'll burn pretty good in a cut (almost as bad a Hoppes #9) , so I rinse pretty fast.

An old pickle will plate copper on steel but not so bad that it can't be removed with a shop towel.  Yes, an old marking compound was made from fairly concentrated copper sulphate.  I like Dykem (or a Marks-a-lot) better.

BTW: another cleaning method I've used is to bead blast things.  That does a nice job of stripping scale from hot rolled steels.   You've got to clean things again afterwards as the dust left behind will interfere with silver brazing.


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## Entropy455

I&#8217;ve had good luck removing oil from freshly machined parts by running them through the dishwasher. Use a little extra Cascade dish washing detergent, and set the dishwasher on &#8220;pots and pans&#8221; and &#8220;high-temp wash&#8221;. . . It&#8217;s not high tech, but it&#8217;s safe, and pretty effective. If your parts are ferrous steel, don&#8217;t let them air-dry in the dishwasher, as they&#8217;ll rust up real quick.

With regard to removing oil from Cast iron. There&#8217;s only one effective way that I&#8217;m aware of &#8211; heat. A lot of heat. You can bake a seasoned cast iron engine block at 600 degrees F for a few hours, and you&#8217;ll cook out all the oil. Then use a gentle steel shot to remove the residual carbon, and also clean up any loose iron oxides. Anyone who has ever had a cast iron engine block &#8220;shake-n-baked&#8221; knows exactly what I&#8217;m talking about. It removes the oil, rust, paint, etc, and makes the part look brand new from the foundry.

For silver brazing steel, you&#8217;ll want to use Type-B flux.

Is the crank pin the same material as the crank? If so, why not TIG weld it together? It&#8217;s a low heat input process (compared to brazing), and you can accurately place small weld beads.


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## digiex-chris

Interesting, that's what I was looking for! rust/limescale remover? That's pretty easy, don't have to go far to get it! Thanks!

Who knew something like silver soldering could be controversial.


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## goldstar31

digiex-chris said:


> Interesting, that's what I was looking for! rust/limescale remover? That's pretty easy, don't have to go far to get it! Thanks!


 
Actually it is closer than you think! Simply vomit and you have hydrochloric acid all ready and waiting. Quite a bit of a basic explosive too  if dried.
Better still have a pee and dry it. You are now a fine candidate for an exteme political organisation

 Nothing controversial , you've been creating these things  all your life.

See what you missed?


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## Entropy455

http://www.everyspec.com/FED_SPECS/O/O-F-499D_21857/

Go to the above link, and download the document O-F-449 (it&#8217;sfree). This is the US Federal specification for low-temperature brazing flux - specifically for use with silver brazing rod (approximately 1250 to 1600 degree F, depending on the alloy of the silver being used). Type A flux is generally used for brazing aluminum bronze. However Type A flux is sometimes used when brazing stainless steel to ferrous steel. Type B is the &#8220;general use&#8221; flux for silverbrazing. 

You do not want to use brazing flux that&#8217;s intended for use with brass rod, as the lower melting temperatures of silver braze will not properly activate the bronze flux. It won&#8217;t properly clean the joint, and you&#8217;ll have poor wetting action with the silver.

Grade-3 silver is Cadmium free, and is also known as Bcup-5. It has the highest melting temperature of the common silver brazing alloys. The advantage is no cadmium exposure. The other advantage is that Grade-3 silver has a wide temperature range of plastic behavior &#8211; where the braze can be applied thick like peanut butter, or you can increase the heat input and get it to flow fast like melted table butter.

Grade-4 silver is 20 percent cadmium by weight, and it transitions from solid to liquid over a span of just a few degrees F. Thus Grade-4 silver will always flow fast and wet. It is difficult to obtain fillet-type beads with Grade-4, whereas you can make nice fillet beads when brazing with Grade-3. Also note that if you use Grade-4, a portion of the Cadmium will become airborne once heated over 400 degrees F. Thus use plenty of ventilation if you use Grade-4.

There are low-cost (DC only) TIG machines out there. They are sold-state, thus they are light weight (no transformers). The advantage is that you can make textbook welds on steel and stainless steel, however becausethere&#8217;s no AC function, you cannot weld aluminum or magnesium. The sold-state technology has really driven the cost of these machines down. You can use an air-cooled torch up to about 150 amperes. There are air cooled torches that are rated for more than 150 amperes, but trust me &#8211; water cooled is the way to go &#8211; and they&#8217;re not that much more expensive. You&#8217;ll also need an Argon bottle with an adjustable flow regulator - one that meters in the 10 to 30 CFH (cubic feet per hour) range. Look into it. These DC only solid state TIG machines are impressively inexpensive. You can get them in both 120 volt, and 240 volt single phase (and both 50 and 60 Hz).


----------



## goldstar31

No Entropy455! I doubt that anyone here will want to bother with what in plain English could be described as the Exuberance of Your Own Verbosity.
The poster wanted to deal with a simple task and provide a quick inexpensive solution. He didn't want to go out and listen to you spouting endlessly on your so called expertise. If you look at the response by the poster to this developing charade, you will notice that he has gone into hiding and has yet to reply.

For me, if that was your intention, do realise that I would have chosen to simply peg the part and drop a couple of bits of soft solder in.
There is no stress in a toy engine to need much more than that.


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## Entropy455

No Entropy455?

As with most things in life - there's more than one way to braze a joint. I linked a federal specification that governs the manufacturing of silver-braze flux. I also identified two of the more common silver brazing alloys, together with some advantages and disadvantages of each.

You implied that barfing and/or urinating on parts is a viable cleaning method. . . .

Aydelott, which posts did you find more useful, mine, or goldstar31's?

So goldstar - I am curious. Earlier you stated that you hold Engineering qualifications. Which qualifications exactly? Please do tell. . .


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## Herbiev

Goldstar31. Please keep it civil. Insulting another members post is not what this forum is about. A question was asked and members provide answers to the best of their ability.


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## goldstar31

Herbiev said:


> Goldstar31. Please keep it civil. Insulting another members post is not what this forum is about. A question was asked and members provide answers to the best of their ability.


Actually I gave sufficient information earlier. It should have sufficed.

What was important was that I gave,or I hope that I gave sufficient information for the original poster to make a basic joint using silver soldering standard techniques. 

The joint could have been made- and has been made by far simpler joining techniques and on that I later commented .

If I haven't given sufficient information to the original poster to solve his problem, I can only offer him my apologies.


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## Herbiev

As the questions have been answered in detail and posts are becoming a little "heated" I suggest closing this thread and move on.


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## digiex-chris

Entropy455 said:


> http://www.everyspec.com/FED_SPECS/O/O-F-499D_21857/
> 
> Go to the above link, and download the document O-F-449 (itsfree). This is the US Federal specification for low-temperature brazing flux - specifically for use with silver brazing rod (approximately 1250 to 1600 degree F, depending on the alloy of the silver being used). Type A flux is generally used for brazing aluminum bronze. However Type A flux is sometimes used when brazing stainless steel to ferrous steel. Type B is the general use flux for silverbrazing.
> 
> You do not want to use brazing flux thats intended for use with brass rod, as the lower melting temperatures of silver braze will not properly activate the bronze flux. It wont properly clean the joint, and youll have poor wetting action with the silver.
> 
> Grade-3 silver is Cadmium free, and is also known as Bcup-5. It has the highest melting temperature of the common silver brazing alloys. The advantage is no cadmium exposure. The other advantage is that Grade-3 silver has a wide temperature range of plastic behavior  where the braze can be applied thick like peanut butter, or you can increase the heat input and get it to flow fast like melted table butter.
> 
> Grade-4 silver is 20 percent cadmium by weight, and it transitions from solid to liquid over a span of just a few degrees F. Thus Grade-4 silver will always flow fast and wet. It is difficult to obtain fillet-type beads with Grade-4, whereas you can make nice fillet beads when brazing with Grade-3. Also note that if you use Grade-4, a portion of the Cadmium will become airborne once heated over 400 degrees F. Thus use plenty of ventilation if you use Grade-4.
> 
> There are low-cost (DC only) TIG machines out there. They are sold-state, thus they are light weight (no transformers). The advantage is that you can make textbook welds on steel and stainless steel, however becausetheres no AC function, you cannot weld aluminum or magnesium. The sold-state technology has really driven the cost of these machines down. You can use an air-cooled torch up to about 150 amperes. There are air cooled torches that are rated for more than 150 amperes, but trust me  water cooled is the way to go  and theyre not that much more expensive. Youll also need an Argon bottle with an adjustable flow regulator - one that meters in the 10 to 30 CFH (cubic feet per hour) range. Look into it. These DC only solid state TIG machines are impressively inexpensive. You can get them in both 120 volt, and 240 volt single phase (and both 50 and 60 Hz).



Good info, thanks! Now I know how to go shopping! It sucks going into the welding shop and not knowing what words I should be talking about.

That's an interesting idea I've had in the back of my mind since I saw one of those little solid state tig machines. I can actually get a setup cheaper than I can get small porta-torch kit. I've been brazing using one of those burnzomatic propane/oxygen combos, which is depleted in about 10 minutes of work and is hard on the pocket book if you need lots of it. I'm going to think more seriously about that.


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## rkepler

digiex-chris said:


> That's an interesting idea I've had in the back of my mind since I saw one of those little solid state tig machines. I can actually get a setup cheaper than I can get small porta-torch kit. I've been brazing using one of those burnzomatic propane/oxygen combos, which is depleted in about 10 minutes of work and is hard on the pocket book if you need lots of it. I'm going to think more seriously about that.



My experience is that brazing needs more heat than high temperature, and that the tool for that job is a large propane/air torch.  Some like the Sievert, I like the Goss.  The smaller ones run about 25K BTU and the biggest I have runs about 300K BTU.  I think the typical torch on a bottle would run about 10K BTU.  Here's an image with the large on the left and smaller on the right:







These are run using fairly high pressure (12-20psi) using a high pressure regulator on an LP gas bottle.  The big one will freeze up a BBQ bottle if you run it fairly long, but it puts out a heck of a lot of heat in the process.


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## goldstar31

In an earlier and less afluent era, I bought a second hand AC welder with 50-75-100 amps outlets. I made up a a pair of carbon arc welders. One was for spot welding car panels whilst the other employed two rods in a sort of jig and generated enough heat to melt prefuxed brazing rods ( not merely silver ones).
It is no use me recommending that  welder but extremely cheap arc welders ( £30 in tht UK) from places  like Aldi and lidl which you have in the US as well as here in UK. Finally, I started to run  16g mild steel rods to replace car panels and to do repair panels. 
It obviates having gas bottles which certainly incur hefty insurance hikes here as well as criticism from the local authorities for both storage and transport in unauthorised motor vehicles.
OK, I'm or was a City and Guilds Motor Vehicle Restorer with all sorts of distinctions and a Certified Welder - and all that jazz but it reached the point where it was no longer permitted to do repairs etc using oxy/acetylene on high strength low alloy steels on vehicle bodies and becoming expert within the law for even home vehicle repairs. 
I suspect that the US etc are far more accomodating in this direction.
Sadly, it is a bit snotty in my neck of the woods where permission is needed to prune a tree- mine are all subject to Tree Preservation Orders and even a small propane or butane gives rise to objections. 
However, I hope that these snippets will be accepted as a guide to others who may be more fortunate


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## Entropy455

http://i797.photobucket.com/albums/yy259/dhem7/DSC03308.jpg

Take a look at this link. (Note: I did not build this part. I simply found the link on Google).

Pay particular attention to the high-quality fillet beads on this brazed joint. These were made with brass/bronze brazing rod, not silver. This joint was almost certainly made with an Oxy-Fuel torch, and not a fuel-air torch. It is much easier to get tight fillet beads like this using the intense focused heat of an Oxy-Fuel torch. A fuel-air torch would&#8217;ve introduced significant heat into the adjacent base material, causing the brass to wet out &#8211; i.e. no pretty beads.

It&#8217;s even trickier to get silver braze to lay nice fillet beads like this, but it can be done &#8211; provided you&#8217;re using a fine tip oxy-fuel flame.  This is where Grade-3 Cadmium-free silver is advantageous, as it flows more like peanut butter, and the Cadmium-based brazing rod wets out real easily.

On the topic of Oxy-Fuel - I recently purchased a complete Oxy-Propane outfit. I was growing sick and tired of paying 80 cents per cubic foot for acetylene. A number 5 acetylene bottle is costing over 200 dollars to fill! 

Acetylene currently costs $0.80 per cubic foot, and contains about 1470 BTU of energy per cubic foot. This equates to $52.45 per Therm of acetylene.

Propane currently costs $2.89 per gallon, and contains about 91,600 BTU of energy per gallon. This equates to $3.16 per Therm of propane.

Oxy-Propane is clearly a significant cost savings over Oxy-Acetylene. . .


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## rkepler

Entropy455 said:


> http://i797.photobucket.com/albums/yy259/dhem7/DSC03308.jpg
> 
> Take a look at this link. (Note: I did not build this part. I simply found the link on Google).
> 
> Pay particular attention to the high-quality fillet beads on this brazed joint. These were made with brass/bronze brazing rod, not silver. This joint was almost certainly made with an Oxy-Fuel torch, and not a fuel-air torch. It is much easier to get tight fillet beads like this using the intense focused heat of an Oxy-Fuel torch. A fuel-air torch wouldve introduced significant heat into the adjacent base material, causing the brass to wet out  i.e. no pretty beads.



I think that process is called "braze welding" and is distinct from "silver brazing", but there are overlaps between the processes.  I expect that you use that form when the area between parts is low or you need a lot of strength (tubing joins in bike frames) and a braze that fills when the area is high or the required strength is low (pretty much everything else).

But you're right, you can't do that with an air-propane torch.  I've done high fillet brazing (silicon bronze) with a TIG but never with a gas.  After getting TIG in my shop it's my preferred point heat source, I don't think I've fired up the gas torch for anything but cutting for 5-6 years now.

Most of the silver brazing I do is like that below (a hand pump in my loco tank):






The bolster on the top of the cylinder, the arms attaching the handle above and the end pieces with the checks are all silver brazed.  Lots of wetted surface and so minimum fillet.

I wonder what the original poster ended up doing?


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