MetalworkingFun Forum

The stuff for copper pipe has a really low silver content and resulting melting point and low tensile strength. Don't think its what you want.

(04-02-2013, 06:17 PM)f350ca Wrote: [ -> ]The stuff for copper pipe has a really low silver content and resulting melting point and low tensile strength. Don't think its what you want.

OK, I'll get the proper stuff. Do you think my propane torch that I use for soldering copper plumbing pipes is up to the task of soldering those two pieces together? That's all I have to work with but I could invest in a MAPP torch if necessary.

Ed

It might be hot enough if you can build a oven with fire brick to keep the heat in. Im not really sure, I always use the OA torch.

Get some Engelhard Ultraflux, and use something like Aufhauser silver alloy A56-T or similar. Try to avoid the cadmium bearing alloys if you can. If you have trouble sourcing this stuff, hit your local HVAC house and get silphos or one of the copper/phosphorous alloys. Plenty strong, but you need a 0.002/0/003 gap or so. And clean. Acetone is good for cleaning.No side effects, but don't use wife's nail polish remover, it has oil content. Don't make the two surfaces to be joined too slick. A 16 Ra finish won't bond as well as a 125 Ra, so rough it up a little if you have to polish it to size.

I've done silver soldering for quite a few years, long before I got an O/A set. For slightly heavier pieces, I often used two regular propane torches. When the whole thing is hot enough, set one aside and keep everything hot with just one while you flow in the solder.

+1 for Tony's comment on Cadmium-free.