Harris S0FB01Type B Solar Welding Flux, 1 lb. Can

Got here quick, great price, this is what you want to use to weld 30x 304 316 321 stainless steel exhaust with tig or any use case where you dont want to have to run a back side purge to protect against back side carbide precipitates. I mix it with heat, the stuff you can pick up at any automotive store to keep fuel from freezing. It is methanol and what is the recommended to mix with the solarflux. Make it into a paste, on the thin side like olive oil consistancy, not super runny but also not stiff like tooth paste. It will harden up as it sits after you have mixed it. You just need to add more methanol or heat to thin it. If you have extra just keep it. It will dry and you can just add the heat and thin it out again. I use an acid brush. Works well. Before you weld make sure it has fully dried out.

Much cheaper (if messier) than back purging. Excess cleaned off easy, interior welds are 95% as good as with 100% argon back purge on stainless headers. Also, a little goes a long way. Once the alcohol evaporates, you can re wet it and mix it back up, never noticed a difference.

For welding stainless steel, when you feel welding with purging gas inside of the pipe is a little too lavish or complicated shape, this one works good. Solar flux prevents the back of the material from oxidized.

This flux is a great alternative to back gassing even when back gassing is possible. I had several 5' long welds on 16 gauge stainless steel and used this flux instead of back gassing. I actually liked the results very well. You do occasionally get some flux flowing up from underneath into the weld puddle, but it doesn't create any real issues. It is very easy to mix up and actually stores well for a couple of days in a well sealed container. It does not take much to cover a lot. This stuff goes a long way. The alcohol does evaporate quickly but you can just add more to the mix to thin it out. The thinner mix seams to work better for me in that it flowed better and actually coated better.

Works good and less expensive than purging stainless steel

I apply it to the inside of each side of SS exhaust tubing before welding and it creates better looking welds and prevents "dingleberries" inside the tube. A friend was having a hard time welding up some SS trim for his Studebaker custom and I loaned him some Type B. He said, "That stuff is the bomb!" It made a noticeable difference in the quality of his welds and the backside was easier to clean up. One can will last you a LONG time.

Welding thin stainless? This stuff is what you need if you cant shield the backside. Just paint this on. It is still possible to burn through and sugar but you really have to get it hot.

Worked as advertised