Stainless Steel oxy-acetilene welding, how-to?

[jakeru]

A neutral, edging slight on the rich side (but just so any "regulator hiccups" don't go lean) is what I have used.

Here is what a book I have sitting on my bookshelf, "The oxy-acetylene welding handbook", copyright 1960 union carbide corporation, says about the topic in chapter 18 "Welding chromium and Chromium-nickel steels", p. 238:

"Flame Adjustment
A neutral flame is preferred for welding the chromium steels. Chromium readily oxidizes so that the use of an oxidizing flame would result in a lowering of the corrosion resistance because some chromium would be burned out. On the other hand, the use of an excess acetylene flame would increase the amount of carbon in the weld, which also would be undesirable. If difficulty is experienced in maintaining a strictly neutral flame, a slight excess acetylene feather is preferred to avoid any possibility of the flame going over into the oxidizing side. The neutral flame protects the molten weld metal from reactive welding gases and from the atmosphere. The proper adjustment of the flame is important in maintaining the chromium content and in promoting sound welds."

I recall if you weld lean or without adequate flux coverage, 304 stainless can rapidly "bubble", indicating extreme porosity and brittleness in the bubbled region. That is pretty bad news and if you see it happening, stop and fix something so it doesn't keep happening. It could be making your flame more rich, or it could be adding more flux coverage, or it could be not making something so hot where it doesn't need to be so hot.


Here is something I stumbled across to get you in the mood. A stainless steel shift linkage I fabricated many years ago, and even used for a while on my race car, I fabricated out of 304 stainless steel and oxy-acetylene welded. This part has never been painted or cleaned, aside from maybe wiped with a paper towel.