# silver soldering



## firebird (Feb 11, 2008)

Hi

Just a quick question. Can stainless steel be silver soldered? If so any tips would be appreciated

Cheers


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## rake60 (Feb 11, 2008)

Yes it can.

This link may be of some help:
Brazing/Silver Soldering Stainless Steel


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## gilessim (Feb 11, 2008)

Funny you should ask that FB , I had to make a piece for my friends motorbike the other day from SS ,that needed to be soldered ( or lets say that it was much easier to solder than to machine from solid!) so I asked my dad, who was a toolmaker for many years, and he told me that he used to solder SS to brass quite often with no problems, just make sure everything is clean!, and use solder with 45% silver at least (low temp.) a good flux and even the newer SS will stick together, Providing there is not too much mechanical force that the piece has to support ,SS seems to hold well, my repair is still whizzing round in my pals magneto, I'll let you know IF it breaks!....Giles


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## firebird (Feb 12, 2008)

Hi

Thanks I'll give it a go

Cheers


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## tbsteam (Feb 19, 2008)

Is there anybody near bolton/bury/greater manchester that does silver soldering?

I need 8 nipples soldering onto 3/16 pipe.

Any help will be appreciated.

Cheers
tb


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## firebird (Mar 1, 2008)

Hi

Whats the best way to clean small steel/stainless steel parts prior to silver soldering?

Cheers


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## Bogstandard (Mar 1, 2008)

FB,
This link will tell you most of what you need to know in laymans terms.

http://www.pollymodelengineering.co.uk/global/technical-notes/basic-silver-soldering.asp

I always use Tenacity 4a for all my silver soldering, and is great on stainless.

John


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## firebird (Mar 1, 2008)

Hi

Thanks John,
         I'm going to read that now.

Cheers


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## Loose nut (Mar 1, 2008)

One point from that web site(Pollymodel engineering), they said to use emery cloth to clean the material before brazing, this is not recommended because the particles can come off and in bed themselves in the material and cause problems with the brazing (silver soldering). That being said most of us do it because it is easier, but if the job is critical then be careful. The recommended way is to use steel wool (stainless steel wool for stainless material, regular steel wool leaves small particles behind that will rust) which is good for copper and brass etc. but is harder to use on materials like steel. I have silver soldered a fair amount of stainless without any problem, just use the right solder and it's matching flux, that's the real secret.


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## firebird (Mar 23, 2008)

Hi

when mixing the flux I tend to overdo it and mix far too much. After a while the flux turns back into a solid in the bottom of the mixing pot. Is it re-usable by adding water and mixing again?

Cheers


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## Bogstandard (Mar 23, 2008)

FB,
Just put a few more spots of water in there (plus one drop of washing up liquid), a quick stir up and it will be ready to use again.

I keep mine in a little sealed container (35mm plastic film canisters or the ones diabetic users have for their test strips are ideal), and it will keep ok until it is all used up.

John


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## Loose nut (Mar 23, 2008)

Flux doesn't have to be mixed into a liquid or paste form to work , it is just fine as a solid, making a paste just makes it easier to apply, just don't dilute it to much or you lose the benefit of it.


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## firebird (Mar 24, 2008)

Hi

I'll start mixing it in a smaller pot with a lid from now on.

Cheers


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## gilessim (Mar 24, 2008)

For small bits, just heat the rod a touch and dip it in the powder, if you have the right flux and your bits are clean, you'll get no overspill of solder that way (flux can attract the solder), if you really need a paste, for larger joints, spit works very well mixed with the flux (really!) they're a lot of gold and silversmiths in my area and this is something I learnt from them, it works honestly!

Giles


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## zeusrekning (Mar 24, 2008)

This is something I will have to learn to do so I can assemble my "Team Build" engine. I bought .0625 diameter silver solder from radio shack. Is this the right stuff? If not where is the best place to purchase solder and flux? I have been soldering a lot lately with my electronics projects and have soldered small pieces of brass together with my regular solder.
Thanks,
Tim


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## Hilmar (Mar 24, 2008)

Tim
I don't think so. I never seen it at RS
Go to a Air Conditioning Place. The one who sell to the service people.
Silver solder is kind of hard you will not cut it with a knife.
For 10 ft you pay probably $10.00- 15.00.
Hilmar


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## Loose nut (Mar 24, 2008)

Usually the only solder you can get in North America is Easyflow 45, unless you special order, I don't know what Radio Shack solder is. The best place to get small quantities of various types of solder and that is vary useful (different melting temps.) is Reeves out of Britain,

https://vault1.secured-url.com/reeves2000/shop_home.asp

They have a large selection, also a good book to get on the subject is "Soldering and Brazing" by Tubal Cain, it's one of the workshop series books (#9) published by Model Engineer or Argus or Nexus or what ever they call themselves these days but commonly available, it will tell you just about anything you need to now for most purposes.


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## gilessim (Mar 25, 2008)

Most of the silver solder used by the AC guys has a high melt point and a lower silver content but its very strong for plumbing joints,for our needs 50-60% silver content stuff IMO is better, it melts at a lower temperature so it's less likely that you'll distort (or melt!) small brass or copper parts. Silversmith suppliers are a good bet, they sell several grades hard to soft and they all flow very well, sometimes you may need to solder one piece and then solder something else near to the first joint afterwards, by using a hard solder first and a soft one for the second, you're less likely to have the first joint come apart from the heat of the second!.

Giles


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## Hilmar (Mar 25, 2008)

From the AC store I got " Safety_Silv 45 and 56 " 
Don't know how that compares with Easyflow 45?
Don't know also if it is the best to use.
"Cadmium Free" what ever that means.
Made by Harris Co. INC in Cincinnati, OH.
You may have RS in GB, to bad we don't have 
reeves in the US
Hilmar


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## Loose nut (Mar 25, 2008)

Hilmar  said:
			
		

> From the AC store I got " Safety_Silv 45 and 56 "
> Don't know how that compares with Easyflow 45?
> Don't know also if it is the best to use.
> "Cadmium Free" what ever that means.
> ...



The numbers in the name usually represent (not always) the silver content IE: easyflow 45 has 45% silver, in Britain the equivalent is easyflow #2 with 42% silver, Safety silv 45 probably has 45% silver, 56 has 56% and may be cadmium free hence the name Safety silv. Cadmium is a common component of some silver solders, it can be very harmful to your health if you breath in enough of it so some types of solder have gone cadmium free, it does change the characteristics some. Reeves ships to the US, Canada and probably to most everywhere else I haven't ordered from them in a while but they where always good before. Another place to try is Small parts Inc. Miami Lakes Florida

www.smallparts.com 

you can get a pretty good selection of solder in various size dia. from them too and if you goggle it there will be others. It is advantageous to get a selection of solder with different melting points and different diameters. Smaller dia. for small work makes it easier to do without leaving gobs of solder all over everything. 

You can also get Sillphos a self fluxing solder that is cheaper than regular silver solder but can only be used on copper and copper alloys, this may be what gilessim was taking about, it works ok but need Oxy-acet. equipment to get the heat to work it properly, and it can't be used to braze model boilers. If the phosphorus in the flux isn't burned out during the solder process it can react with sulfur compounds in the fuel you use in the boiler, primarily coal, and will cause deterioration of the solder joints until they fail. Also beware of the silver solder sold in hardware stores, it usually has a low silver content around 5%.


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## shred (Mar 25, 2008)

Jeweler supply stores carry solders of every conceivable kind (silver, gold, platinum.. ) as well.


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## compound driver 2 (Mar 26, 2008)

Hi
Easyflow 2 for boilers, carries cadmium so use in a sensible way. Silverflow 55 can be used as a replacement for Easyflow2 advantage is its cadmium free. 
I now use AG303 for boilers, no more breathing cadmium for me! The cadmium helps the solder flow but thats part of the job the silver plays.

For general silver soldering go with silverflow2 (ask for AG303)

Whatever you use it needs to go onto a very clean surface. On copper pickle the ciopper in either sulphuric or acetic acid. With ferouse use a file or wire wool DONT use emery cloth it contains grease and the emery imbeds in the metal.

On copper boilers nothing but silver solder will do. With the exception of assembling large crown stays using siphbronze. On the crown stays this is ok due to the size of the fillet formed.

Mix your flux using water and a small drop of dish soap, or mix with metalated spirit and be aware that the meth will burn off very fast. Dont use spit unless you want to add grease and oil to the joint. 

Either way make no mistake cadmium WILL kill you so dont breath it in.

cheers kevin


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## Mcgyver (Mar 26, 2008)

> For general silver soldering go with silverflow2 (ask for AG303)



i think you mean AG103? AG303 is easyflo and AG103 is silver flo 55

Kevin, any comment on how much harder it is to use that easyflo? when everything is clean and well fluxed the easyflo wicks in so nicely - same with the silverflo?


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## compound driver 2 (Mar 26, 2008)

Hi
Oops I typed that lot just after getting out of the pit leaving a warm wife and going into a cold shed.

The cadmium free seems to flow almost as well as the Easyflo2 as long as the joint is tight and theres plenty of heat. I did four reasonably big gauge 1 boilers using silverflo with out any problems a month back.

If asked I would say easyflo2 is a better solder but silverflo is so close its not worth breathing in the cadmium.

cheers Kevin


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## gilessim (Mar 26, 2008)

No offense here but I wanted to say that spit has a lot of enzymes and acids in it ,and can be used a a flux by itself, there are no fats in it, it also contains h2o2 (hydrogen peroxide), when heated it's an extremely good cleaning agent! , I'm sure you're right about it not being suitable for boilers because you have a lot of experience with them, I didn't want to mislead anyone!. The Romans used to use borax mixed with spit to solder jewelry and I'm pretty sure that most flux today is just borax and ammonium chloride, For SMALL stuff there is no need to make a paste, it can just make a mess!, anyway this is just my experience, just do some trial runs and see for yourselves!


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## rickharris (Mar 26, 2008)

AFAI can tell all silver solder and brazing fluxes are variations on Borax mixes. Not sure about the spit mind!


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## Loose nut (Mar 26, 2008)

A good pickle for copper brass etc. is battery acid (about 37% sulphuric acid), dilute it 7 to 1 with distiled water. It's weak, but will still clean copper in a few minutes, wear googles anyway, don't risk your eye's. The best part is after you have used it for a while it turns blue, at this point you can dip clean steel in it and it will plate out a thin copper finish, good for marking out with. 

With easyflow 45 silver solder the best gap is .003", any less than .0015 and the solder won't wick into the joint, capillary action can't take place with that thin a gap. Any more than .005" and the strength of the joint will start to diminish, the larger the gap the faster the strength falls off. If you take an automatic punch, space marks around the parts you want to join, it will make raised dimples about .003", then lightly clamp together and solder away. If you don't fasten the parts together before soldering when the flux melts the parts will move on you at the worst time. Good luck, soldering is all about practice.


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## gilessim (Mar 26, 2008)

Please ,just forget that I ever mentioned spit!


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## firebird (Mar 27, 2008)

Hi

Ok I got a problem now. My wife has just broken the little ring off her best silver necklace. With all that new soldering kit you have bought surely you can fix my necklace she said. The question is can I do something that small and delicate with the kit I have. Urgent help needed here gentleman. If I can fix it big brownie points will be earned which equates to more shop time. If I fail I'll never hear the end of it. Any tips will be greatly appreciated.


Cheers


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## J. Tranter (Mar 27, 2008)

Loose nut  said:
			
		

> A good pickle for copper brass etc. is battery acid (about 37% sulphuric acid), dilute it 7 to 1 with distiled water.


Is that 7 parts water or acid?
John T.


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## Mcgyver (Mar 27, 2008)

firebird  said:
			
		

> Hi
> 
> Ok I got a problem now. My wife has just broken the little ring off her best silver necklace. With all that new soldering kit you have bought surely you can fix my necklace she said. The question is can I do something that small and delicate with the kit I have. Urgent help needed here gentleman. If I can fix it big brownie points will be earned which equates to more shop time. If I fail I'll never hear the end of it. Any tips will be greatly appreciated.
> 
> Cheers



you secretly take it to a jewellers but let her believe what a clever chap you are and how usefull all that shop stuff is. Seriously though, I wouldn't make that your first SS attempt, there's a very good chance the end of the necklace will end up a molten hunk of silver. think in terms of tryin to braze brass with a bronze filler


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## Loose nut (Mar 27, 2008)

J. Tranter  said:
			
		

> Is that 7 parts water or acid?
> John T.



Sorry, seven parts water to one part battery acid. The end result is around 3% acid, weak but will still clean the metal quickly and burn your cloths and burn your eyes and dry your skin out so be careful. It will also clean the flux off after soldering, be careful dunking hot metal (not advised), the splatter and steam is weak acid. Best to let it cool off first and do a little scrubbing.


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## Loose nut (Mar 27, 2008)

firebird  said:
			
		

> Hi
> 
> OK I got a problem now. My wife has just broken the little ring off her best silver necklace. With all that new soldering kit you have bought surely you can fix my necklace she said. The question is can I do something that small and delicate with the kit I have. Urgent help needed here gentleman. If I can fix it big brownie points will be earned which equates to more shop time. If I fail I'll never hear the end of it. Any tips will be greatly appreciated.
> 
> Cheers



Been there and done that. You need to get 1/64 th Dia. solder and a very small tip with a very small flame, lot of flux. The secret to good silver soldering is the use of the proper flux. The flux at first will turn clear and gooey and many people and the solder at this point and make a mess. If you have the right flux that matches the solder after it goes gooey it will turn liquid almost watery and the base metal will appear to become cleaner, this is the point to touch the solder to the work. The proper flux is made to liquefy just before the melting point of the silver solder.

At this point cross your fingers and if you screw it up "prepare to kiss thine ass goodbye" a woman scorned, you know the rest.


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## Loose nut (Mar 27, 2008)

gilessim  said:
			
		

> Please ,just forget that I ever mentioned spit!



What about drool, I'm not trying to get it in the flux it just happens that way.


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## Mcgyver (Mar 27, 2008)

Loose nut  said:
			
		

> seven parts water to one part battery acid. The end result is around 3% acid, .



i use 10% myself, kept in a plastic bucket with a resealable lid....no doubt 3% safer, is the only difference how quick the pickle works?


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## Bogstandard (Mar 28, 2008)

Gents,

Using burning acid is good, gets the job done a lot faster.
But what has to be realised is the safety issue here. 

A lot of members won't have the luxury of a sealed chamber for a workshop, where only the owner can get in.

Surely citric acid is a much safer recommendation, a lot slower, but won't involve a lot of heartache if the kids or animals manage to get into it.

What is best? A couple of minutes in a potentially lethal mixture, or an hour in a solution that in theory you can drink without coming to too much harm.

If your silver soldering is that good, there should be hardly any residues left to clean off anyway.

John


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## J. Tranter (Mar 28, 2008)

Where can you get citric acid here in the states?
John T.


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## Bogstandard (Mar 28, 2008)

In the UK it is used for all sorts.

Cooking, home beer brewing (we have some weird hobbies), drug taking. Pharmacies should sell it, some specialist food stores might have stock, but the usual place is the home brew shop.

Mix up to a saturated mixture (it usually comes in powder form), pop it into a plastic container with a sealed lid (a good use for those grotty old Tupperware containers that are never used). Drop your bits in when needed, take out when clean, a rub with a finger will show when it is clean underneath the muck. Don't worry if you forget about it being in there, it won't get 'eaten' away.

It lasts for ages.

John


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## compound driver 2 (Mar 28, 2008)

Hi
On copper boilers I always use sulphuric acid at about 25% ish. I have a tank of citric but only use that for the last pickle and for descaling boilers each year. 

Battery acid at 3% would work but in all honesty would take as long as citric acid to work. Sulphuric can be had reasonably easily in the UK and the US. We used it in America for making anodizing baths and for cleaning prior to silver soldering or brazing. In the UK its harder to find but people like Blackgates will sell it as will Reeves (check that one). 

What ever you do DO NOT drop hot metal into acid be it sulphuric or citric if you want to keep your skin and luings! You also stand a good chance of shocking the joint and ending up with a brittle solder.

Cheers Kevin


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## gilessim (Mar 28, 2008)

Nothing wrong has been said in this post, I asked Boggie a while ago about the citric acid bath and he explained in some post ,I can't remember which, how to use it and the fact that it's hard to get hold of in the UK because it's somehow used by druggies, it maybe the same in the US! but I found some yesterday in an Indian shop, it's used for making pickles and such, it's also used in beer and wine making, as is ascorbic acid (vitamin C that costs about $1 a kilo in brewing stores here in Italy instead of $10 for 100 grams in the pharmacy!), my father-in-law is an industrial chemist and informed me that the safest acid for cleaning copper based alloys (apart from citric, like John says maybe safest of all!) is phosphoric acid 30-40% by volume, used to correct ph imbalances in soil also, you just dunk the soldered metal in for 10 seconds or so and it works a treat!, it's still an acid so you should always be careful! but it's much more stable and safer than H2SO4!.

Also remember when diluting acids always add the acid to the water and not the other way round!

Giles


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## compound driver 2 (Mar 28, 2008)

Hi
Citric in the Uk is about 75p for 100 grams and thats enough for 1/4 gallon of water. When I use citric i mix two gallons water with 400-500 grams of citric powder. Most chemists will get it for you or stock it in 100 gram bags.
Its worth pointing out I do this for a living so stronger acids are a big advantage time wise. If its for a hobby then take the safe rout and dilute further.

Cheers Kevin


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## Loose nut (Mar 28, 2008)

compound driver 2  said:
			
		

> Hi
> 
> 
> Battery acid at 3% would work but in all honesty would take as long as citric acid to work. Sulphuric can be had reasonably easily in the UK and the US.
> ...



The acid I use at 3% will clean copper or brass for soldering in about 5 minutes, a little more if it is really dirty and leaves a matt finish, so it might not be any good if you want a polished look when your done. Citric acid is available in most grocery stores in North America, it's used for canning some types of food, another mixture is ordinary vinegar (acetic acid) mixed with salt but I don't remember the ratio, it works about the same as pure citric acid mix. In Britain there was a company selling "Four H's" (not sure of the spelling) pickling for model engineers, suppose to be safe, they advertised in Model Engineer magazine and they may still be around. Sulphiric acid is dangerous to children, animals and idiots so if you are going to use it, do so safely.


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## rickharris (Mar 29, 2008)

Citric acid is available in every supermarket in the UK as Kettle descaler - Check the Ingredients on the packet.

I use it as an acid pickle for jewellery - it works quite quickly (relative to safety pickle) and smells nice. 

the druggies use it to manufacture crack Cocaine I believe. I guess they could always squeeze a lot of lemons.


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## compound driver 2 (Mar 29, 2008)

hi
My only issue with citric is the time it takes to remove flux from a joint. I always worry that it leaves flux inside the boiler at the end of the build. For that reason I always pickle in sulphuric. Having said that I do use citric acid on some jobs and its handy to just drop a boiler in the citric at the end of the day.

We all have to be happy with what we use to do these jobs be it work or hobby. Personaly I have no problem using strong acids, I am aware of the safety issues and I also am aware of the safety equipment that I need to use. 

Most small silver soldering jobs will work fine with nothing more than a polish of the bits with scotch brite, but some jobs have to have a degree of cleaning way past this. 


Cheers kevin


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## Bogstandard (Mar 29, 2008)

Kevin,
Don't get me wrong, I used to use sulphuric, but the safety issues when the grandkids came along, forced me into using a safer method.

What I personally was worried about, was someone with very little knowledge of its handling. Emptying an old battery, using it, then someone having a serious accident.

As you mentioned, there is a great difference between amateur and professional workshops.

In the restricted, kiddie and animal runaround areas we tend to use, the safest solution is the best, even though maybe not the most efficient.

John


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## compound driver 2 (Mar 29, 2008)

Hi John
I fully agree. 

My pickeling tanks are locked up at the end of the day as are the fresh acids. 
One of the other poinst is keeping chemicals seperated from each other, thats sometjing not many give thought too in the amatuer workshop.

Im all for safety in every walk of life.

Cheers kevin


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## firebird (Mar 29, 2008)

Hi

I managed to fix the wifes necklace. I found some old cheap and nasty silver jewellry to practice on and very quickly discovered that the propane torch I have even with the smallest jet fitted was far to big. I found that with a No. 1 jet in the oxy/acet gear I could get a really small flame. Holding the necklace in one of those little helping hand things with the magnifying glass I put some flux on (spit mix) wrapped a tiny amount of very fine silver solder round the joint to be repaired and brought the torch slowly in. In seconds the solder melted and fixed the broken joint. Today at least I am her good books and can spend the rest of the afternoon playing. On the subject of citric acid I bought mine from Wilkinsons. Its in the home brew section.

My daughter has just handed me a piece of paper with instructions for making a solution to clean old coins. She got it off a TV prorammme she was watching. Has anyone tried it?

normal salt
normal vinegar
warm water from the tap
mix together, put coins in and count to 10


Cheers


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## SignalFailure (Mar 29, 2008)

Depends on the coins firebird - if they are silver just wrap them in "tin foil" (aluminium foil) and drop them into boiling water with a little vinegar for a few minutes. The vinegar is optional as is the water really! Just holding/rubbing old silver in foil will produce heat, lovely sulphery bad-egg smells and a clean coin. I've used the method to *delicately* clean coins up to 2,000 years old with no ill effect.


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## AKViking (Mar 29, 2008)

As a jewelry artist who works primarily in silver (gold is just too expensive to use much!) and just getting into machining, I've followed the silver soldering thread with interest. Although it may seem counter intuitive, when silver soldering (especially with silver because it conducts heat so well) you want to use a large bushy flame (neutral), not a hot oxidizing flame to solder. You also want to warm the whole piece up to almost the temperature that the solder will flow (the flux turns glassy) before concentrating the heat where you want to solder. If you just heat the spot where the solder is, it will ball up and generally won't want to flow into the joint. Also be careful not to overheat or keep hot too long. Chances are you will burn your flux off and the piece will oxidize and the solder won't flow. When the solder flows remove the heat. A simple bottle propane torch with a bushy flame should provide more than enough heat to solder unless you are soldering something with a lot of mass. Remember, the solder will actually follow the heat so with a little practice you will learn to "pull the solder" into where you want it.

I really enjoy this forum. Keep up the good work everyone!

Chris in Ketchikan, AK


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## firebird (Mar 30, 2008)

Hi Chris

I didn't mention in the above post that the necklace in question is a very fine sort of chain strung with beads of some sort so I couldn't risk a large flame for fear of doing more damage but thanks for the tips anyway

Cheers


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## rickharris (Mar 30, 2008)

SignalFailure  said:
			
		

> Depends on the coins firebird - if they are silver just wrap them in "tin foil" (aluminium foil) and drop them into boiling water with a little vinegar for a few minutes. The vinegar is optional as is the water really! Just holding/rubbing old silver in foil will produce heat, lovely sulphery bad-egg smells and a clean coin. I've used the method to *delicately* clean coins up to 2,000 years old with no ill effect.



In the UK perhaps use CILLIT BANG (A cleaning agent) the TV advert shows it cleaning a coin in 15 mins. It contains citric acid.


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