Silver solder

[pminmo]

I need to solder some brass, small stuff, very little mass, .02 probably as thick as it gets. I need the melting temperature to be above 800F. I'd like to use a small butane microtorch. Stay brite stuff has to low of melting point, I'n not sure if the higher silver alloys (11xx+F) can be done with a microtorch. Any experience out there? Or a suggested solder? I don't want to buy lbs of solder, an OZ or two is probably all I need to buy.

Thanks

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[Mcgyver]

Phil, most of the silver solders are 1100+ F so you should be ok. not sure about the burning temp of butane iirc its close to propane....i use propane and it works perfectly. Oxy Acetylene is a lot more difficult because its is too hot - wrecks the flux of you are not careful about applying it indirectly. Use only if what you are soldering is so massive it sinks a lot of heat. do you have SS experience? happy to give you some basics if not. as for sourcing SS, I've always gone to welding supply places or industrial supply for it, have you checked the usual large supply suspects, msc etc?

[pminmo]

I've done lots of soldering with regular solder and stay-brite "silver solder". I would assume using the approate cleaning methods, appropriate flux for the filler it would be similar? i.e. at liquifation temp, with the filler and material at that temp it will flow and bond the same as regular solder, and if the material isn't at liquifacation temp, it will cold joint ?

Supposedly butane can deliver 2300F.

[Mcgyver]

you've got it.

don't know 'stay-brite' - is it a brand of silver solder?

added tip would be to cut the SS into small pieces, place in the flux. start warming everything up, you reach a magic point where the SS is 'stuck' in the flux and won't blow away. it goes into a ball shape, and then when metal hits the right temp beautifully wicks in. advantage of this is a very clean joint with no excess solder. technique as per Kozo Hiraoka; one incredible machinist, author and illustrator.

http://www.craftsmanshipmuseum.com/Hiraoka.htm

a lot of what you see in the pic below is an apparatus i made to hld things for SS'ing, but you can see the small pieces of SS at the joint.

http://i20.photobucket.com/albums/b2...rsoldering.jpg

just for kicks, here's the result - there are 5 seperate SS joints on this all done with the same temp solder

http://i20.photobucket.com/albums/b2...trassembly.jpg

[pminmo]

Yes stay bright is a silver solder brand/formula, but its a real low melting point 4xx.

[Geof]

I've done lots of soldering with regular solder and stay-brite "silver solder". I would assume using the approate cleaning methods, appropriate flux for the filler it would be similar? i.e. at liquifation temp, with the filler and material at that temp it will flow and bond the same as regular solder, and if the material isn't at liquifacation temp, it will cold joint ?

Supposedly butane can deliver 2300F.

Butane or propane will get plenty hot enough for silver solder and it will flow by capillary action in a good clean joint as good or better than soft solder. The strength is much higher than soft solder and can actually exceed many brasses.

If you Google 'braze 450' you will get buried in hits; even a wikipedia one!

[pminmo]

Thanks Geof,
Your right, lots of info and maybe answered part of my confusion. Since I'm wanting a temperature of 800F to be solid, looks like by definition that is brazing. That opened a whole different world of filler solutions than "silver solder".

[Geof]

Thanks Geof,
Your right, lots of info and maybe answered part of my confusion. Since I'm wanting a temperature of 800F to be solid, looks like by definition that is brazing. That opened a whole different world of filler solutions than "silver solder".

There are four categories (I think) if you want to get picky: soft solder which is your electrical stuff, hard solder which is the plumbing version, low temperature brazing... braze 450, and high temperature brazing which is regular brazing or bronze welding.

[diecutter]

Pminmo,

I use three different high temperature solders. Easy silver braze 650 (melt 1240F: flow 1325F), medium silver braze 700 (melt 1275F: flow 1360F, and hard silver braze 750 (melt 1365F: flow 1450F). The different melting points allow you to solder on new details without melting existing solder joints. A small Mapp gas torch works great with these solders. I can send you a small sample of each of these along with the proper high temperature flux so you can decide which if any of these suit your application. These and other silver solders are available from www.riogrande.com as well as other sources.

[ViperTX]

You can also get the silver solder used for refrigeration systems from your local welding supply store....just tell them what you want to do.....the silver solders from rio Grande supply are mainly used for jewelery....not sure of the differences in the alloys.....

[Geof]

...the silver solders from rio Grande supply are mainly used for jewelery....not sure of the differences in the alloys.....

The difference? Simple; $$$$$$$$$$

[handlewanker]

The main thing with silver solder, no matter the grade, the joint must be close. Silver solder adheres to the surface and the strongest bond is when the two surfaces are close together.
If you want to fill a gap then braze it.
The other golden rule is to heat the joint and the solder will draw in as soon as the joint is ready.
If you get the heat on the solder before the joint is up to temperature then you risk vapourizing the silver content and everything gets messy.
I used to do silver soldering jobs for the aircraft industry and they're pretty fussy.
Ian.