Printable Version of Topic

Posted by: VaccaRabite Mar 30 2023, 12:23 PM

Yes, I know people prefer to TIG stainless. I don't have that. I have the same 120v Lincoln welder that I have been using for the past 15 years.

I also have a set of SSIs that I can practice on and maybe repair before getting to the main task of adding an 02 bung to a different set of SSI pipes.

So, what's the process? Gas mix? Obviously it needs to be really clean. Any specific filler spools I should be looking at?

Zach

Posted by: Root_Werks Mar 30 2023, 02:14 PM

I recently went through this with my 120V Mig. It requires the wire and different bottle. Totally forget the type of gas, but it worked great. I'll probably never use it again, but it was neat to weld SS.

Posted by: 914_teener Mar 30 2023, 02:34 PM

stainless for the wire of course and "tri mix". Helium, Argon...and the slightly oxidizing C02.

Its spensive....I'd TIG the SS Heat boxes though. MIG weldng with stainless starts to get diminishing returns below 14 Ga due to the way distortion is added with the load of wire and heat affected zone. If you don't care about the added distortion or the slight oxidation of the weld...then ok.

But....it's always worth the lesson by doing.

Posted by: Geezer914 Mar 30 2023, 03:12 PM

Instead of welding an O2 bung in the SS heat exchanger, weld the bung some where in the muffler unless that is stainless also. Welding the bung in the heat exchanger is only going to read 1 cylinder.

Posted by: VaccaRabite Mar 30 2023, 04:53 PM

I’m aware.
My new engine was tuned with the bung in 1 pipe. I have a muffler bung that I could use already. But if the engine was tuned for a specific thing, I’m going to attempt to recreate it. I also got a lot of reversion in my old engine using the muffler bung as it was too close to the tail pipe. Fine for WOT but would get reversion and read a bit lean at idle and off throttle.

Zach

Posted by: 914_teener Mar 30 2023, 05:07 PM

Oh...filler wire suggestions.

I'd use 304L L is for low carbon. Remember SS work hardens and on the SSHI they've been worked. Think mostly that's why they crack. Ton's of threads on that as you know. But if it's just for practice....go for it.

Posted by: 76-914 Mar 30 2023, 05:39 PM

Just get some SS wire. I've welded bungs to 16ga SS tubing using the std 75/25 gas that I use for regular steel. No problems. Welded fine. SS is actually easier to weld than plain steel in my book. Start your arc on the bung close to the thinner SS tube and you'll be fine Zach. I've also welded the 3/8" steel exhaust flange off the headers on the Suby to 16ga SS with the same results and never a problem. Just concentrate the heat towards the thicker metal so you don't blow a hole the thinner tube.
I can send you some SS wire if you want to try it out.

Posted by: nditiz1 Mar 30 2023, 08:26 PM

Zach do you want to barrow my TIG? I bought it off Ben. It's what he used for a long time before upgrading.

Posted by: VaccaRabite Mar 31 2023, 08:26 AM

I went to the local welding supply store this morning thinking I was going to get some 025 SS wire and a small bottle. The owner of the store is one of those old school guys that gives one customer 100% of his attention till that customer is done. Great if there is not many people in the store, sucks if there is a crowd. Today there was only one other guy before me - so not bad.

I told him what I was doing. He listens and says "I'll sell you a bottle if you want, but I can save you a little money if you want to try flux core SS wire." The wire is a bit thicker then I wanted at 035, but no bottle needed and a little more tolerant of contamination - which is going to be a fact of life with used exhaust pipes.

He said this wire was new to the store (he did not have it in his computer yet) but it was really popular with a fab shop in town and he had started stocking it for them.

So, I'll try it. a 1 pound spool was a little spicy at $44, but I did not have to spend over $100 for a bottle. I'll practice on the SSI that is already broke, and see how it goes. The bung should get here Saturday or Monday Maybe good, maybe shit.

Zach

Posted by: Superhawk996 Mar 31 2023, 08:48 AM

So no one is going to mention back purge or is it being assumed?

Posted by: mb911 Mar 31 2023, 09:01 AM

Tri mix or just bring it somewhere local. For $50 you could have someone tig weld it in

Posted by: Spoke Mar 31 2023, 04:20 PM

I just welded an O2 bung on the cat of my 930. The cat is SS. I bought a spool of SS wire and cranked the power all the way up using the bottle of whatever you MIG weld with. Besides my sucky welding skills everything worked out well. I had to weld a SS bolt next to the bung as I feared I would damage the bung when replacing the bumper.



Attached image(s)

Posted by: VaccaRabite Mar 31 2023, 05:03 PM

@http://www.914world.com/bbs2/index.php?showuser=3031 that's pretty much what I expect my weld will look like. As long as its strong and does not leak no one will see it.

Zach

Posted by: Spoke Mar 31 2023, 05:27 PM

I welded the bung better than I did for the bolt. The bolt was an afterthought right before I replaced the bumper.

Posted by: mb911 Apr 1 2023, 06:10 AM

What does a 1 lb spool of stainless cost right now? Again take it to someone that can do it with TIG and ensure it won’t leak or break out. For local guys I charge $30 weld one on.