Welding Tips and Tricks

Hey guys -

I am pretty confident with TIG'ing aluminum and mild steel. But I just tried stainless and I was not liking the results. I am not really well setup for stainless yet I don't feel; I don't have a setup for back-gassing the weld with argon, I think was my main problem. I also don't have any of the super side gas coverage cups. (I do have a #8 gas lens I think is about my best at the moment. I think the #8 gas lens works better than a #10 standard collet body cup I've also got.) I was welding some automotive exhaust tubing, which was mild steel I think, perhaps a mixture of some stainless components I wad welding on. Some pieces were "new", some were old (prepped the fornt side, dirty/carboned back side though.) I tried the 309L filler rod and found it was oxidizing on the back side where the argon couldn't reach, it was particularly horrible for filling wide gaps. There were occasions (filling a wide gap, or hole) where I could see the stainless oxides "swell up" (like a porous bubble inflating inside the material.) Ick. The oxides I feel were really messing up the "fluidity" of the puddle and I knew I wasn't getting good penetration with it like that either. E70S6 Mild steel rod was so much more fluid and easily workable on the same materials, in comparison. So I'm pretty sure to tackle more stainless projects successfully, I need to do something to better shield the back side of the stainless weld. (And perhaps even better shield the front side.)

I was just wondering if rather than messing around with back-gassing with argon (second flow meter, hose setup plugging apparatus, etc) if anyone is having success using "Solar Flux B" with TIG on stainless. I have used this when oxy-acetylene welding stainless, and it worked really well. Dare I say, with the solar flux, oxy acetylene welding stainless was more fluid, and went even more nicely than oxy acetylene welding mild steel without any flux! I still have some of the flux, and remember dissolving some in alcohol, and painting it on the weld joint (back, front, and in between.) The flux itself also seemed to stay quite inert after welding, so I didn't even need to hassle with removing it from the inside of the pipes (automotive exhaust, not "food grade" projects were talking about here.) Oxy welding stainless with flux did make quite the mess on the front side of the stainless weld however, and considerable mechanical effort was required to remove it and get a presentable looking result.

I was just wondering how well the Solar Flux works with the TIG process, since I haven't tried it yet, I know the flux manufacturer says it works. But I'm wondering if it makes a big mess of the appearance of the TIG beads? Is is possible to solar flux the back side of the weld and TIG it, and having it turn out nice looking without having to take a power stainless cup brush to remove the flux afterwards? Is anyone using it, or tried Solar Flux with TIG and have any comments? Should I just skip it and invest in the setup necessary to back gas welds with argon? I want to weld automotive exhaust, maybe some art work, who knows, probably not any food pipes though. Thanks.

By the way, here is the link to the online product info for Solar Flux "B":
http://www.solarflux.com/Pages/Productinfo.html

Edit: I was just reading the instructions on the manufacturer's web site. Interesting that they recommend a product "Wonder gel" for removing the flux residue if wire wheel is not preferred. I found this about it: "Wonder Gel cleans the toughest slag, scale and heat color from stainless steel." Interesting... removes heat color too. I wonder how visually attractive a stainless steel solar fluxed, TIG welded, Wonder Gel cleaned surface would look. Compared to the "industry standard" pure argon shielded with argon back gas option.
http://www.derustit.com/cart/index.php? ... cts_id=207

Jake,
on flat plate you can take a plate of copper and clamp to the back of the section you are welding for gas coverage but on tubing if there are any gaps at all you will need to back gas the tubing to get cleaner welds on stainless.
I have not heard of using a flux on tig but you never know , if it works give it a shot.If you are going to be doing a lot of tubing you will need to get a second regulator or just t off your main reg line to back-gas the tubing to get a clean weld with stainless.
Stainles is tough for sugaring.
Gary

I use Solar Flux B on stainless exhaust work with good results. First, if it is bench work, like headers, I would back purge. But, on the header to rear of the car - typically 3" stainless, long pieces, it can be difficult to back purge. I mix the flux with Heet to form a paste, clean the stainless (304) with sand paper (180 to 220 grit). I only put the paste on the inside, not the outside. I use 308 filler - 309 if stainless to mild steel. I try to keep the heat as low as possible - with .063" wall stainless, 1/16" tungsten (2% thoriated or Lanthanated) at 50 to 55 amps. It got rid of the "sugaring" problem on the inside of the welds.
Hope this helps.

I havent tried it, but on another thread, someone posted that you can use CO2 for a back purge, which is a whole bunch cheaper than back purging with argon.

And now I have tried solar Flux "B" for myself on TIG'ing stainless.

I put it on the inside of a stainless steel header, when repairing crack, and building up a weak (thin) weld between flange and collector. It worked well for at least the first welding heat cycle (pass/layer/stringer). On subsequent welding heat cycles, the old flux was not reliable, because the flux, now converted into a black, glass like coating, could fracture off from the heat related expansion/contraction, leaving unprotected stainless. If this were welded again, it could cause "oxidized stainless boogers" - not good!

I also put it on the front side in one spot I had a hole I needed to patch, and needed all the extra flux shielding I could muster. I probably could have also dipped my filler rod in the flux, but didn't think to at the time. The black glass like residue is pretty hard, tenacious stuff - scraping with a sharp, dental scaler wasn't even effective in removing it! (But, there is no match against a carbide burr however. )

Anyhow, where the flux residue had just fractured off (I think this makes a tiny, glass breaking / "tinking" sound), the appearance of the revealed metal was absolutely bright, silvery, oxide free. So it is possible to make very sound welds with this, if one were to use the proper technique.

jakeru wrote:Hey guys -

I was just wondering if rather than messing around with back-gassing with argon (second flow meter, hose setup plugging apparatus, etc) if anyone is having success using "Solar Flux B" with TIG on stainless. Thanks.

I don't believe Jody has done this video yet (hopefully coming soon ), but I saw Mr. TIG did one recently...

http://www.weld.com/index.php/Log-In-To ... p-gas.html