Silver Brazing

By HHHoagie Date 03-29-2001 23:51

Would it be possible to silver braze 16ga stainless steel, lap joint, with a propane torch? If there is not enough heat in propane, would MAP gas work. I'm trying not to have to use an acetylene torch. Don’t have one at home!
I have read one of the articles by W. Daniel Kay on silver brazing and it doesn’t seem to require much heat!
Anybody venture some advice? Thanks.

By RonG

Date 03-30-2001 01:49

Yes you can. The alloy you use matters but up to around 50% silver brazing alloy will melt around 1200 F and flow around 1300 F.

You will need a flux for the higher alloys. There different fluxes for different applications.

Seeing as how SS oxidizes very quickly Your work should be very clean, preferably fresh ground, sanded or buffed. We use denatured alcohol most of the time.

By HHHoagie Date 03-31-2001 01:07

Well thank you two, Brad and Ron for your advice and taking the time to answer my post.
Brad, I'll do a search on the Thomas Registery for that Wisconsin Co. as you suggested. Thank again
Bob

By BP Maas (**)

Date 03-30-2001 17:53

As Ron said there are different fluxes to use, the selection is essential for good wetting on stainless steel because of the tenacious oxide film.
There is a company in Wisconsin that can help you select the right flux, unfortunatley I can't remember the name. You will be able to find them in the Thomas Register online by doing a search for "brazing".
Best of luck with your endevour, Brad

By Darvin

Date 03-31-2001 08:48

I haven't done any silver brazing in a long time but I use to use a product called Ultra flux. It's nothing more than ground up Boron mixed with water. Our plating shop used some pretty caustic stuff to clean the stainless. I think it was Nitric acid. You might be able to buy nitric acid at the welding supply because I think nitric is the ingredient in stainless soldering flux (like I said, it's been a while).

If this is your first time silver brazing stainless I can give you a pointer. If you see signs of it turning black, stop, re-clean your part and start over. Once stainless starts to oxidize, it's over. And try to put brazing paste between the joints before assembly if possible.