# silver solder



## blockmanjohn (Jun 19, 2016)

I have to silver solder some unions to make up steam pipes for my recently completed Stuart beam engine. I have never done this before and am looking for advice on instructions and what supplies I will need. Also where to purchase the supplies. Thank you in advance, John.


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## chucketn (Jun 19, 2016)

John, you need to put your general location in your profile so we know how to advise you. It wouldn't help if I told you where to get supplies in the US, for example, if you are in the UK.
Basically, you need solder containing silver, a good flux, and a torch. I use Harris solder and flux available at my local welding supplier. A Bernzomatic Maps gas torch from Lowe's provides the heat.

Chuck


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## blockmanjohn (Jun 19, 2016)

Thanks for pointing that out Chucketn. I fixed it.


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## chucketn (Jun 19, 2016)

I have done some silver soldering, but am no expert, by far. I am holding off on the how-to for the more experienced folks. I do have some instructions saved somewhere. I'll see what I can find that might help.
Have you done any kind of soldering? Plumbing, electronic? Methods are similar, but heat is hotter and the solder is harder. Cleanliness of components to be joined is still a definite requirement. Less is best, no "bigger the job, the bigger the blob" techniques...
BTW, I'm originally from Sidney, NY, near Binghamton.
Chuck


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## blockmanjohn (Jun 19, 2016)

I have done quite a bit of soldering plumbing fittings. What type of flux is best? I have seen many types when I looked in Amazon. John


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## chucketn (Jun 19, 2016)

I have only seen and used white flux, but have heard there's a black flux also. I'll have to go out to the garage and dig out my soldering kit.

Chuck


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## toolznthings (Jun 19, 2016)

There are two fluxes , a white flux good for temperatures in the normal range of the silver solders 1200 degrees. A black flux is good up to around 1800 degrees and I doubt that you would need it. I make sure I get cadmium free solder which is safer to use. Good ventilation require regardless of the choice. Also the flux can always be " revived " with the addition of a little water if it drys out in the jar.
Kind of brief, but I hope this helps you.

Brian


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## gbritnell (Jun 19, 2016)

1. Clean the joints.
2. Flux with white flux. Coat beyond the joint area and this will keep the metal from discoloring.
3. Use a high silver content solder or braze as some call it. Usually for pipe joints or small items I use 54% silver solder. 1/16 diameter solder is good. 
4. User a pair of side cutters and cut some small pieces off the coil of solder. No longer than .04-.05 long. 
5. Using a propane torch start heating the area until the flux starts to get clear (looks like water droplets). 
6. Using a pair of tweezers or needle nosed pliers lay a piece of the silver solder into the flux. Have a small rod handy to keep the solder in place. It will try to roll around the pipe. 
7. Start heating the joint again (slowly) If you overheat it you have to start over. Keep the piece of solder against the joint by just touching it with the rod. Don't hold the rod against it. 
8. When the joint is hot enough the solder will soften and flow around the joint. Remember, solder flows toward the heat. If it looks like the solder has melted at the spot it was sitting but didn't flow around the joint completely move the torch to the other side of the joint. For small thin sections this isn't generally needed as the parts will absorb enough heat to flow the solder. 
The reason I use this method is because if you try and touch the solder stick to the joint once it gets hot the heat from the torch will soften too much solder and you'll get a big clump of solder on your parts. It's not that it can't be done this way but it takes practice and a steady hand. 
To clean the solder from the joint use an old sauce pan (preferably glass) Boil some water and put the part in. This will soften and clean the flux from the part. 
gbritnell


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## bazmak (Jun 19, 2016)

Point 2,you mention to coat the flux beyond the joint.I find that this
pulls the solder to all the fluxed area.I find it better to flux ONLY the joint area
better joint and less solder to clean off.Not being critical,just my thoughts Regards barry


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## goldstar31 (Jun 19, 2016)

I would agree with Mr Brttnell and have ticked ,a like,However when a bigger solder job comes up you have to run the heated fluxed rod along the joint. Again, you may have upgrade the heat source. I always used a soft flame with oxy acetylene &#55357;&#56832; 
It or oxy propane is a very useful skill to acquire because with a little more know how, you can braze or join steels or whatever. Most jobbing garages have ,bottle set, in the corner.

Wishing you all well. ---from Fiji

Norman


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## Blogwitch (Jun 19, 2016)

For pipe joints, try to obtain silver solder wire, I use 0.5mm diameter.
Wrap a length around the pipes you are trying to braze to form like a spring, then cut the spring along the length to form a few 'rings'.
Mix flux with a tiny bit of water with one tiny drop of washing up liquid in it, I use a small tupperware container to mix mine in, and if it dries out over the years, just add a tiny bit more of water to regenerate, it should have the consistency of unwhipped whipping cream.
Slide one of the rings onto the pipe and dip the end of the pipe into the flux and push the joint together and wipe off any excess flux, you need the flux down the joint, not all over the pipe. Slide the ring of solder down to the joint and just apply heat around the joint. The joint should form in a few seconds, job done.
Drop joint into some saturated citric acid and leave it to pickle for an hour. Lift out, wash in water and rub around the joint with some wire wool, dry and it is ready for assembly.





































Hope this helps

John


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## jayville (Jun 20, 2016)

Norman...very well explained...clem


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## goldstar31 (Jun 20, 2016)

jayville said:


> Norman...very well explained...clem



What has to appreciated is that 'the joining process' goes from something like my late wife's orthodontic work wth a mouth blown little alcohol burner with little brass tubes to a battleship. It's like that.My worst experience was teaching an older bloke, who was doing a 5 inch Simplex boiler and had a heart attack with me feeding him with nitro glycerine on the way to hospital.:fan:

Well, now? 
Norm


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## Blogwitch (Jun 20, 2016)

John,

If you are having trouble sourcing what you require, I am quite willing to send you some wire and a great flux (tenacity 5) in the post, but it might take a while from UK to USA.

John


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## blockmanjohn (Jun 20, 2016)

Thanks to all for  the expert advice. I know your time is valuable and I really appreciate the help. There is no doubt in my mind that I can now do a good job of completing the steam pipes. John


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## gus (Jun 20, 2016)

blockmanjohn said:


> Thanks to all for  the expert advice. I know your time is valuable and I really appreciate the help. There is no doubt in my mind that I can now do a good job of completing the steam pipes. John



Hi John,

Gbritnell and Blogwitch have given best advice and both are highly experienced at silver brazing. Heating Power is very important. Silver brazing is in fact best over soft solder. I use Mapp Gas Torches for small jobs and 30---40% Silver Content for best results. Mapp has single burner/twin burner/,three burner torches. I use three burner torch.


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## Philipintexas (Jun 20, 2016)

First, why use silver solder? soft solder is probably adequate for this application. That said, no-one emphasized it enough, CLEAN the surfaces.. That means bright metal cleaned with emory paper immediately before heating. Also, a non-oxidizing flame source. I find Mapp or propane has less tendency to oxidize the metal during heating. Also, the molten solder will tend to be drawn toward the heat source, apply the heat away from the opening and it will draw the solder toward the heat. Also, leave some clearance for the solder to penetrate, a really tight joint can't allow solder to flow into it


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## Wizard69 (Jun 20, 2016)

Lots of good advice here.   I can't say I've shiver so,Derek anything but have done a lot of plumbing with soft solder and a bit of arc  welding.   One key aspect that needs to be stressed with all of these processes in that the metal has to be clean, this even applies for arc welding.   Clean metal makes all the difference in the world.  

When doing copper pipe the old phrase "if it isn't pink it isn't ready" is often used by plumbers.  You want the copper or brass completely clean of corrosion or oxidation.  This means both the male and the female parts of the joint.  

While not related to this question clean metal is also required to get good results with many welding processes.  People will try to rely upon the flux for cleaning action be it a weldments or soldered connection, this is a bit foolish and can lead to joint issues. Cleaning should be considered of primary importance when joining metals with any of these processes.


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## Wizard69 (Jun 20, 2016)

Philipintexas said:


> First, why use silver solder? soft solder is probably adequate for this application.


It might be, it all depends upon how hot the joint gets and if there are any mechanical demands to be concerned with.   I do believe silver solder will lead to a better joint though.   


> That said, no-one emphasized it enough, CLEAN the surfaces..


This needs to be stressed over and over again!!!    Clean surfaces are an absolute must to get good results.  


> That means bright metal cleaned with emory paper immediately before heating. Also, a non-oxidizing flame source. I find Mapp or propane has less tendency to oxidize the metal during heating. Also, the molten solder will tend to be drawn toward the heat source, apply the heat away from the opening and it will draw the solder toward the heat. Also, leave some clearance for the solder to penetrate, a really tight joint can't allow solder to flow into it




Obviously this is a bit different than some of the assemblies for engine building but when I was taught plumbing type soldering the goal was to heat from one side.    You knew the joint was hot enough when solder meta led on the side opposite where the torch was.  This unfortunately doesn't work well with oddly sized parts.  If one part is far more massive than the pipe you need to heat the massive part of the assembly first.


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## Blogwitch (Jun 21, 2016)

Just to answer a few of the queries raised in previous posts.

Why not use soft solder?

To put it bluntly, it is just not a strong enough joint. When working on small engines, vibration has to be taken into account, and with a soft soldered joint, they fail all too often because of this problem.
A good hard soldered joint (silver soldered or as the US call it, silver braze) should be almost indestructible.
I carried out a test to determine how strong the joints were when making steel to copper joints while building my Paddleducks engines, and I think this picture tells all, the joint just wouldn't give way, the actual copper pipe eventually failed.






I forgot to mention about cleanliness, but I have found over the years a very good method.
I clean the joints with carpenters steel wool, this has no oil preservative on it unlike general purpose cheapo wool, which has oil on it to stop it corroding.
So basically, I rub over the joints with wire wool, then wipe everything over with a bit of spirits (denatured alcohol or Isopropanol), I find that this is enough.
Do not use anything that has grit on it, like emery or sandpaper. If any bits come off onto the joint area, it can penetrate and get incorporated into the joint and cause a weak spot, if you get any steel wool in the joint, it just becomes part of the joint.
I personally don't go to great lengths with cleaning purely because I use a perfect flux for this type of work.
Here in the UK, unlike the US and other parts of the world, we have specialists who make such things for industry and model engineering, and you can obtain a variety of fluxes and silver solders to join almost all materials that can be joined by such methods. So for people who are not in the UK, dig deep in your pockets and buy yourself a tub of Tenacity 5 flux, you will never regret it. This flux was designed for silver soldering stainless steel, but it works with everything else. The main advantage is that it cleans the material as it is being heated up and withstands temperatures where other fluxes would have given up and caused a failed joint.

I haven't bought any 1/16" silver solder rods for many many years, it is just too cumbersome to use when confronted with tiny joints, you tend to get the solder everywhere. You need very little solder to form the joint, and any excess is a waste of this expensive item. I use either 0.5mm wire, used as shown in pictures above on my previous post or silver solder sheet, which is about 0.005" thick. This is cut into what are called 'Pallions' using normal scissors, and is placed onto or into the joint, using the flux like a 'glue'. It is then just a matter of heating up the largest part of the job and the solder will automatically flow into the work, giving you perfect joints with no need to file all the excess solder off, as if you have calculated right, there should be no excess at all.

For cleaning up afterwards you use a process called 'pickling'. There are lots of potions and lotions that people use, from heavy highly dangerous acids and alkalis to mothers' pickling vinegar.
You can't go far wrong by going into a brewing shop (in the UK) and buy yourself a kilo of citric acid crystals. This should last you the rest of your life.

I mix it up by using say a pint of warm or hot water, and gently adding the crystals until you see that no more are being absorbed into the water. This stuff is so safe you can just add sugar and feed it to the mother in law as lemonade.
I keep this in a tupperware sealed container and use it until it no longer does it's job.
Just drop the soldered bits into it and leave for about an hour. The parts should come out nice and clean and can be then polished up with a bit of wire wool. Don't worry about leaving it in there too long, the workpiece shouldn't suffer, in fact, I left a part in my pickle for many months, and it didn't suffer any ill effects at all.

For heating the job up to carry out your soldering.
For me, say the job is equal to a 1.5" cube of material or smaller, I would use just a plumbers butane/propane soldering torch, and larger than that, I would get out my larger propane blowtorch that is supplied by a large gas bottle, in fact if it is a really large job, say a loco steam boiler, I would get help and use two blowtorches, a big one for heating the main part of the job and a smaller one for localised heat.

Where many people go wrong is that they don't put enough heat into the job and the solder just won't 'flash' into the joint. This then causes a problem, the solder you have just heated up and turned into a ball on the surface of the job has change properties, the melting temperature will have risen and will require even more heat and flux to get it to remelt.
There is a fine line between too little and too much heat in the job, this is where a long lasting flux is required, it gives you a longer working time. If you heat up just the major part of the job and watch the solder itself, once it has reached the perfect heat, it will 'flash' into the joint, any more heat and you are liable to 'cook' the joint and it will be weak. 

So basically, keep an eye on the solder, I sometimes use my tinted driving glasses so that I can see when the solder has flowed, through the glare from the hot metal.
Sometimes it is all over in a few seconds, other times you can spend half an hour getting the job up to working temperature.

NEVER point the torch at the solder, ALWAYS at the major part of the job.

It is all to do with practice and experience, then more practice and experience.

I hope that this has helped a little.

John


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## blockmanjohn (Jun 21, 2016)

Hi Blogwitch,
Thanks for the expert advice and your generous offer. I am going to order my own tub of Tenacity 5 flux, and 0.5 mm wire. It should last the rest of my life.
Thanks again, John.


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## gbritnell (Jun 21, 2016)

Well stated John!
Explaining things sometimes becomes a tangential issue. Well if I say this then I have to add that and if I add that then I will have to add more. 
With the basics explained it's surely a matter of practice to get good joints. Once a person learns the routine it just becomes second nature. 
gbritnell


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## gus (Jun 21, 2016)

*Soft Solder v/s Silver Solder.*
I was making Tubal Cain's mini steam boilers. Seen my welders doing silver brazing which gave me the wrong impression that any layman could easily do it. 
I thought I could get away using canned LPG Gas and got nowhere. Alternative was use soft solder which I thought I could get away. While making steam and running the mini oscillating engine,the water level went low and the soft solder gave way. My airconditioning fishy mate gave me some good advice. Bought Mapp Gas Torch and from there my silver brazing happened and improved and boiler joints no longer gave way. Takes time to master. 
Gas Fired Tractor Engine was made 5 years ago. Pardon the grime.


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## gus (Jun 23, 2016)

Blogwitch said:


> John,
> 
> If you are having trouble sourcing what you require, I am quite willing to send you some wire and a great flux (tenacity 5) in the post, but it might take a while from UK to USA.
> 
> John



Currently struggling 1mm Silver Brazing Rods. Please advise source for 0.5mm
Rods. Just Silver brazed a 4mm tube into a pump casing. 1mm rod is hard to cut and place on job. Quite happy with the results. Trust all is well there!!


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## Philipintexas (Jun 23, 2016)

GUS: Does the layout fluid keep the SS from sticking? Or, did you clean it before soldering?


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## Blogwitch (Jun 23, 2016)

Gus, or anyone else wanting to order what I showed.

Go to here and then download their catalogue (free), then go down to PDF page 121. Also while there, download their order form.

http://www.blackgates.co.uk/catalogue.html

You will soon see the silverflo 55 wire and the Tenacity flux.

Also, have a look through the catalogue as there just might be something else that you need, they stock most things relevant to model engineering.

Gus, I would send you some, but unfortunately, customs in countries in the far east have a bad habit of thinking the small packets of very fine white flux are something else, and open the package, then when they fail to find what they want, they just dump the whole lot in the bin, this is assumed, as I have twice tried to send a package like this, one to Thailand and one to Hong Kong, both failed to arrive. Australia, US and South Africa where OK.

John

BTW Gus, get a BIG hammer, and flatten out your silver solder rod until it is a few thou thick, then you should be able to cut small pieces off it to place around the joint, I also use this method with soft solder, saves putting too much on. It also helps reduce stress.


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## bazmak (Jun 23, 2016)

Although cut and place is often used it is not the be all and end all
Get the job to temp ,dip the end of the 1mm rod in flux,flux the area and touch the rod to the job the solder should just flow round.I very rarely use cut and place


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## Blogwitch (Jun 24, 2016)

Baz,

Everyone to their own methods and I wouldn't want to force anyone to follow my lead.

It is just that I, for many many years have found that what you call cut and place perfectly adequate for 99% of what I get up to. The only time full rods were used was on large jobs such as a boiler, where even then, all the stays were soldered in by putting rings on them. The only time we used rods was when we did the foundation ring and main boiler seams.

How could you use a rod on these, which I used to make for a commercial model locomotive company, if I had used a rod, it would have just been a big blob of solder.






It also allows several parts to be soldered at the same time, just place the solder on the joint, and sweep down with the blowtorch, as you do one, it starts to heat up the next one to it. Usually all done in less than a minute.











A little time in the pickle and a rub with wire wool to remove the flux and job done.






No excess solder anywhere, plus NO WASTE. I keep every tiny little offcut of the wire or sheet in the knowledge that it will complete a joint sometime in the future. It is just too expensive to throw or file away because excess was used.

John


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## gus (Jun 24, 2016)

bazmak said:


> Although cut and place is often used it is not the be all and end all
> Get the job to temp ,dip the end of the 1mm rod in flux,flux the area and touch the rod to the job the solder should just flow round.I very rarely use cut and place




I get good results with one very small silver on the job piece. Have tried dipping the rod into the job and I get a big glob. Sigh.:wall:

For bigger jobs I do OK with rod dipping.


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## gus (Jun 24, 2016)

Blogwitch said:


> Baz,
> 
> Everyone to their own methods and I wouldn't want to force anyone to follow my lead.
> 
> ...



Hi John,

Would be great to have you as a neighbour. So much to learn from you.
The pump failed.Now making another with ball bearings. Preliminary trial was good with ball bearings inside pump housing. The small DC motor did spin the shaft.


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## Blogwitch (Jun 24, 2016)

So sorry about the pump failure Gus, you WILL get it right with a little perseverance.

As you know, the more experience you get, the less scrap goes into the recycle bin. 
Everything is a steep learning curve, and even now, because of people asking questions and me replying to them, my experiences are starting to return, as I lost most of them due to some treatment for PTSD I had a while back.

So keep asking questions, and maybe I will remember a lot more and get back into my shop a lot quicker as at this time, it would be no use being my neighbour as with most of the stuff in my shop, I have either forgotten what they are for or even how to use them correctly. If I was to do even a small machining job, I would have to spend an hour trying to remember how to go about it.

Keep up the good work.

John


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## Wizard69 (Jun 25, 2016)

Blogwitch said:


> So sorry about the pump failure Gus, you WILL get it right with a little perseverance.
> 
> As you know, the more experience you get, the less scrap goes into the recycle bin.
> Everything is a steep learning curve, and even now, because of people asking questions and me replying to them, my experiences are starting to return, as I lost most of them due to some treatment for PTSD I had a while back.
> ...




I have a simple question for you, what did you mean by pickle?   I assume it is submersion in some sort of cleaning fluid or acid.  Your work comes out looking extremely nice by the way, thanks for posting.


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## Blogwitch (Jun 25, 2016)

Hi Wiz,

If you go up to post 20 I think, the one with the twisted pipe, after that picture it tells you exactly what I use to clean before soldering, and a bit further down, after I have finished soldering and how to clan things up.

John


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## blockmanjohn (Jun 27, 2016)

Is it safe to assume that the citric acid solution can be used over again until it no longer cleans the flux? Should I just keep it in a capped jar until I need it gain?
Thanks, John.


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## goldstar31 (Jun 27, 2016)

Of course, brown sauce is also satisfactory.

Mind you, I rarely use any concoction. Sort of old school. It follows all those air conditioning and fridge units which abound all over the world. Do they 'clean up'? No way, life is too short.

However a hint about small items?  Why not use silver solder paste and restrict the run of melt with an HB pencil or Tippex to keep things neat? My late wife taught me on that.

Norman


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## Blogwitch (Jun 27, 2016)

John,

I use my citric acid pickle until it is no longer effective. Depending how much you use it it could be a few months or a couple of years.

There are commercial pickles available from engineering suppliers, and they do work a lot quicker, but the failing point for me is that you have to wear safety equipment with it, gloves, glasses and sealed tanks. The thing about citric acid is that unless you have an open wound, where it would make your eyes water if you got some in it, it is totally safe to handle and have knocking about the shop, and can be disposed of down the drain without any complicated neutralizing treatment.

John


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## Chiptosser (Jun 28, 2016)

For those of you that want different thicknesses of sliver solder.

The material is malleable.   
Use a small hammer, and pound it to the thickness that you need. You can then use scissors to cut it to width and length needed. 
I have done this for many projects.

Good luck to all.


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## goldstar31 (Jun 28, 2016)

Chiptosser said:


> For those of you that want different thicknesses of silver solder.
> 
> The material is malleable.
> Use a small hammer, and pound it to the thickness that you need. You can then use scissors to cut it to width and length needed.
> ...


 
More or less agreed. I use what is 'to hand' and cut with a pair of snips which were originally used to cut orthodontic or piano wire. They also crop up on my Mig welder.

What hasn't been mentioned- and I think that it is worth a mention is that once the silver solder has melted on the job, it loses silver to the job and becomes more difficult to re-melt- should the need arise.

The other point that perhaps is worth mentioning is the necessity to find a method of 'raising the dottle' which few will readily interpret. However, it refers to bringing out the dirt and inclusions in the weld pool. Dottle is Northumbrian for the nasty mess in the bottom of a smoker's pipe.

I suspect that I learned about it  at a tender age in the blacksmith's shop when my father was brazing or gas welding. Usually it involves a circular motion to bring up the stuff which will cause weakness or porosity or both.

Some of the older home locomotive boilermakers etc suggest  using  a stainless steel little wire brush. I've got one, came with an arc welder but never used it .

Whatever the choice, it is pretty well what Henry Bessemer did when he blew air into the blast furnace.:fan:

I'll leave it at that

Norman


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## Blogwitch (Jun 28, 2016)

Chip,

It has already been mentioned in my posts above.

BTW Gus, get a BIG hammer, and flatten out your silver solder rod until  it is a few thou thick, then you should be able to cut small pieces off  it to place around the joint, I also use this method with soft solder,  saves putting too much on. It also helps reduce stress

Norman,

Same again.

Where many people go wrong is that they don't put enough heat into the  job and the solder just won't 'flash' into the joint. This then causes a  problem, the solder you have just heated up and turned into a ball on  the surface of the job has change properties, the melting temperature  will have risen and will require even more heat and flux to get it to  remelt.

That is why I read the posts completely rather than just skimming through them

John


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## Chiptosser (Jun 28, 2016)

Blog-    You mentioned sheet stock!,  unless someone else mention hammering their round into flat.

Some people my not think to thin their material down, by hammering.  Sheet stock Silver solder is not a common item, readily available off the shelf. 

I am just making it know, that people can make their own thin material to the thickness of choice, without purchasing it.


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## goldstar31 (Jun 28, 2016)

Wearing a bowler hat and a jazzy waistcoat ex my late wife's obsession with all things saxophone etc, may I suggest that some of the 'insurmountable problems' in this topic are already solved.

My wife had a Ferrees musical instrument repair catalogue in which all these problems were listed and solutions found.

Might I commend its pages as an interesting source of professional information  for lesser mortals- like me?


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## Chiptosser (Jun 28, 2016)

I am sorry that I missed your suggestion to  Gus to thin the material. 

Lets just say, I was reiterating it, to others who also may have also missed your suggestion for thinning material.


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## Blogwitch (Jun 29, 2016)

Chip,

Here in the UK you can get silver solder in a lot of different shapes and sizes.
I bought 20ft long by 3" wide of very thin sheet a couple of years back, that should see me out.

Photobucket is down at this time otherwise I could have shown how I flatten out soft solder and use it INSIDE  of a joint, which I use when I don't think I can get enough penetration over a large surface area from the edges to join parts together for machining.

I wasn't pointing a finger at all, just mentioning that if people don't read a whole post, and inwardly digest, lots of useful information can be missed.

Hopefully, this weekend I will get into my shop and make a short vid showing just how easy silver soldering can be done by almost anyone.

John


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## moerman (Jun 29, 2016)

I would like to learn more about "raising the dottle" or other ways of cleaning the joint. Do you mean to clean while the solder is molten? Or is it just a way of saying to clean thoroughly in advance?


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## goldstar31 (Jun 29, 2016)

moerman said:


> I would like to learn more about "raising the dottle" or other ways of cleaning the joint. Do you mean to clean while the solder is molten? Or is it just a way of saying to clean thoroughly in advance?


 
So far, I think most will agree that with increasing practice, it will be possible to physically 'stick' two bits of similar or dissimilar metals together with silver solder. The real test is whether the joint is able to stand steam and possibly superheated steam.  Reams of comments have filled the pages of books and whatever about 'boiler testing'. Whether we like it or not, boilers will leak- they might even follow what used to happen in full size- and blow up. The policy is to eradicate leaks as far as is possible.
In the joining process, we have obviously used the best materials and the best possible practices to attempt to not introduce both non metal. 

I think that sort of introduces the subject. If we do a dummy test of our competences, and cut through our joint, we will find that it is not quite textbook.
From this, we can and should try to remove as many things which cause leaks as we can. Despite fluxes, cleanliness and whatever, we can try to remove as much rubbish that we introduce into the weld pool.  

If we keep the weld pool molten, we can 'fish' the problems out with either a pin pointed torch flame which literally digs and lifts the air and inclusions to the surface. 

To answer the question yet to be posed, can this be done with a blow lamp?
Well, I can't do it and I am something called or was called a Certified Welder or a holder of a City and Guilds Certificate in Motor Vehicle Restoration-m amongst a heap of equally useless qualifications. 

I can or could - with a pointed flame lift the impurities which gives rise to most of the leaks which are our lot. With a broad -any old heating source, the answer from me- is no.- or you might be lucky. y

Does this make other views topsy turvy?  Well make your boiler, fill it with water, double your pressure- under water- of course and judge the result.

Back to trying to dealing with jet lag, zillion bean counting entries in far more difficult problems.

Cheers

Norman


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## Coomba (Jun 30, 2016)

Just curious, these boilers you guys reference to. What are their working pressure?


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## goldstar31 (Jul 1, 2016)

Coomba said:


> Just curious, these boilers you guys reference to. What are their working pressure?


 
I picked my much battered copy of LBSC's book on 'Maisie' as the easiest to hand- and one which gives somewhat dated but non the less useful instructions to beginners. 'His' test of Maisie's boiler was 180psi.Not, I emphasise , the working pressure.

This is not the answer that you are seeking but 'Curly' Lawrence went on to discuss the needed strengths and bending and bulging of the copper sheets and tubes that were necessary and expected to get his little loco to safely perform. 

As an aide memoire, might I mention -yet again- that I retired almost 32 years ago- not from making pennies from boiler making but counting beans?

Consequently, might I humbly suggest that you physically  seek out Live Steamers who will give a far clearer picture of the current world of model steam.

Laughingly, I always wonder what dear old George Stephenson would make of all this internet stuff, bearing in mind that he could successfully design and run a full size series of steam locomotives- but couldn't read or write.
If we follow the converse of my argument-- say no more:hDe:

Norman


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## bazmak (Jul 1, 2016)

When making model steam locos the only thing not to scale is pressure


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## Coomba (Jul 1, 2016)

bazmak said:


> When making model steam locos the only thing not to scale is pressure


 
I looked up the working pressure of a steam locomotive, and it said starting out 200-250 psi. High pressure loco. begin at 350 and reach up to 1500 psi. That's wild. What pressure do you run in yours?


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## bazmak (Jul 2, 2016)

Most of the steam locos I was familiar with ie Gresley pacifics etc worked on 180 to 250 psi working most of the main lines of the UK
Models however work at lower pressures  but not scaled down
My last model was Hielen Lassie a 3.5g pacific.If I recall the boiler had to tested
to 200psi and worked at half that.Most small oscilating models can work
between 10 and 50psi. Just my thoughts rule of thumb


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## goldstar31 (Jul 2, 2016)

Coomba said:


> I looked up the working pressure of a steam locomotive, and it said starting out 200-250 psi. High pressure loco. begin at 350 and reach up to 1500 psi. That's wild. What pressure do you run in yours?


 
I think that the questions are now being aimed beyond the genuine seeking of practical help.

As far as I know, Britain has one 'new' locomotive and this was at a cost well beyond the purses of the average modellers. There is one associate of mine who is actually making one- himself. I am advised- keeping my distance.

In our earlier discussions, I think that it was on the metacentric heights and subsequent dangers from  icing of tugboats in the Baltic, I fell asleep at 3AM.  My only regret was that it wasn't earlier

'Nuff said

Norman


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## Coomba (Jul 2, 2016)

bazmak said:


> Most of the steam locos I was familiar with ie Gresley pacifics etc worked on 180 to 250 psi working most of the main lines of the UK
> Models however work at lower pressures but not scaled down
> My last model was Hielen Lassie a 3.5g pacific.If I recall the boiler had to tested
> to 200psi and worked at half that.Most small oscilating models can work
> between 10 and 50psi. Just my thoughts rule of thumb


 
bazmak
Thanks, for a straight answer.


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## Jasonb (Jul 2, 2016)

The limiting factor with most small boilers is that they are usually made from copper so you don't see many above 100psi working pressure. Model traction engines in the larger scales tend to have steel boilers and will have a working pressure of 200psi or a little more, this also gives better compounding  as there is more expansion of the steam over a greater pressure range.


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## Owen (Jul 3, 2016)

Golden rules of all soldering is clenthliness, make sure both parts are shiny clean.  Mix the flux into a paste and apply to the joint PRIOR to fitting the two pieces together, do not use to much flux, just a little on a tooth pick is sufficient, remember where there is flux the solder will run. You do not want to see the silver solder after you have completed the joint, remember silver solders strength is in its cappiliary action, it will flow where the flux is.  A little is far better that pouring silver onto the joint.  That would imply to brazing not silver soldering or soft soldering for that matter.  Last point is the cost of the silver solder rod, the percentage of silver determines the price, I always use 50% silver content ans a 1.2mm rod.  Hope this helps?


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