Silver solder will not melt ?

Hi,

I am not a jeweller, but I am a musical instrument maker that uses silver soldering. For a little while now I have been having a problem with certain jobs with the silver not melting or fluxing, which can be very frustrating. I use a 'Bullfinch' propane torch. The funny fhing is that I don't recall having always had this problem. Does the torch give less heat as the bottle gets emptier ? Should I be using another make of torch ? I have had this torch for well over 30 years. I have one bigger nozzle that gives more heat but the flame is very big.

I need to solve this problem as the job can become very messy to clean when it has been under the torch for so long just to get the solder to melt and flow.

Thanks for any advice guys !

First thing that I'd ask is - given the age of the torch - what condition is the hose in (and for that matter the regulator)? Hoses perish & degrade internally as well as externally, and I've had a few regs give up the ghost over time.

Temperature has a massive effect on the evaporation of the propane - while in use, the bottle can chill down significantly reducing the available gas pressure; one solution is to stand the bottle in a water bath (and chill beers in the water bath...). Ambient temperature of the bottle is similarly unhelpful. But ultimately, until it's pretty empty, unless the bottle gets cold then the pressure should stay above the pressure set on the regulator.

" chill Beers " though you liked it warm up there.

Depends entirely on the beer. And cellar temperature is not that warm (as someone who used to work as a cellarman... :) ).

Silver solder should flow within a minute or two, or you will need more heat. Also the piece needs to be heated overall by moving the flame around, before homing in on the joint.

Prolonged ineffectual heating burns out the flux and changes the solder alloy.

The common flux in jewellery making is borax in water.

Remember also that you are not restricted to hard silver solder. For a large metal instrument, you will be greatly helped by using easy, or extra easy hallmarking quality silver solder. Dennis.

Hi,

I am really struggling here because I have been silver soldering for years without much of a problem and now suddenly what should be relatively easy jobs have been almost impossible, I'm tearimg my hair out as I cannot understand what the problem is ? Let me first of all explain that I am not a jeweller but I am a musical instrument maker and do a lot of silver soldering.

I am soldering brass in various thicknesses both flats and tubes. I am using materials I always have used i.e. easy flo flux powder and the lower temp' melting silver solder wire. However, suddenly the wire solder will not melt and flow no matter how much flux I use. This morning I have been trying to do a job which I have done many times but it just will not work ? I was thinking that the propane torch is suddenly not giving enough heat, but, the brass is glowing red and ready to start melting ! Surely at that temperature the silver solder should melt and flow ?

Any ideas ? THANKS !

Sometimes you can get bad solder, maybe its wort getting a small piece of new solder and trying that ? If its hot and clean enough it can only be solder or flux I'm guessing.

Merged with previous thread.

Try the solder on another item, does the solder melt on it's own eg. on a solder block, did you buy the solder from your usual supplier, are you fluxing the join or just dipping the solder ( you say you are using a powder flux )
is the solder Jewellers grade or industrial type silver solder

Hi Guys, first of all I apologise for my late response, I was not aware that anyone had responded !?

To follow on from my posting earlier today..... I have been trying to do a job I have done many many times without problem. After 3 or 4 attempts trying different things like making sure the water I mix the flux powder with is clean, I tried yet again and this time the brass melted before the silver solder did ? Surely the silver solder should have melted and flowed at a temperature high enough to melt brass ? Bear in mind this is a job I have done counless times successfully. I was questioning the heat of my torch but if it can melt brass surely it cannot be that !? I am confused, stumped and frustrated......

Quote:

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Originally Posted by china

Try the solder on another item, does the solder melt on it's own eg. on a solder block, did you buy the solder from your usual supplier, are you fluxing the join or just dipping the solder ( you say you are using a powder flux )
is the solder Jewellers grade or industrial type silver solder

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Hi, it is the same solder, same flux and same method I have used for years. I put a small cut of the solder wire and flux on a brass plate and it did melt and flow, although it did seem to take a while longer than I would have expected. I cannot recall the exact name of the solder wire but it is Cookson, 1mm and the lowest melting point available, the flux powder is what I have always used - easy flo - Thanks

Quote:

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Originally Posted by Dennis

Silver solder should flow within a minute or two, or you will need more heat. Also the piece needs to be heated overall by moving the flame around, before homing in on the joint.

Prolonged ineffectual heating burns out the flux and changes the solder alloy.

The common flux in jewellery making is borax in water.

Remember also that you are not restricted to hard silver solder. For a large metal instrument, you will be greatly helped by using easy, or extra easy hallmarking quality silver solder. Dennis.

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I actually use extra easy 1mm dia.

Before going back to Cookson, just try one last trial....clean your solder with a rub of sandpaper, it could be oxidised.

I would agree with Les. If nothing else has changed and it’s been lying about then it is probably dirty. I rub down my solder strip before every use and before cutting pallions