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Can you braze stainless steel?
I have a car header that began cracking at the weld between the tubing and the flange. The header is ceramic coated from the factory so when I welded the cracks I wanted to minimize the destruction of the coating so I TIG welded it with stainless wire. During one of my welds I got too much heat in it and blew a hole in the tubing and welded it back up. The problem is that the weld cracked so I welded the crack three more times and watched it crack again as it cooled. I'm assuming that either some of the header coating contaminated the metal or some carbon from inside the header tube is causing this to happen but I'm not sure what to do about it. I want to add that I do not specifically know what the coating really is as far as chemical makeup, etc. and this is the only weld of four that is cracking on me.
I'm considering the following options:
1. The crack is on the bottom and will not be seen so I was planning on brazing it but I heard you cannot braze stainless because it will not stick. Is this true?
2. Weld it with an oxy-acetylene torch with mild steel filler rod.
Thanks in advanceClay Skarovsky
hobbyist - New Braunfels, Texas
Clay, I don't know enough about your parts to say what's wrong with the welding in the one out of four pieces. Yet you certainly can braze stainless steel. We do it often in our vacuum furnaces using commercial braze paste. As a hobbyist, you'll likely be well served by chatting with someone at Wall Colmonoy or Handy and Harmon. In fact, H&H have done the world a fine service (kinda like Ted here) by putting their very nice Brazing Book online- just Google the term 'brazing book' and read what it says about stainless steel brazing.
By four welds, I was speaking of the four tubes of the header (V-8), all of which were at least partially cracked. The only one that repeatedly cracked upon cooling was the one I burned a hole in first and then filled it in.
I checked out the online book and it clearly supports brazing stainless. My original question should have also asked if you could braze stainless using a brass filler rod.
What I ended doing was re-melting the filler material with an oxy-acetylene torch and trying to cool it slow and it hardened without cracking.
Thanks for the input.Clay Skarovsky