Newby question about SS gas

By RenoHuskerDu Date 07-01-2011 09:47 Edited 07-01-2011 11:54

I didn't see a forum for introductions, so I'll do it here.

I'm a hobby welder living in France. I mostly weld on our vehicles or those of friends. For example, I build my own exhaust systems from discarded new 60mm SS tube +1 meter long. I recently picked up a very clean 95 BMW V8 for an amazing price, and want to weld on its SS exhaust.

I bought some ER 316Lsi wire .8mm for my GMAW. It's a TelWin "TelMig 180/2" short-arc rig, which I bought barely-used from a bankrupt autobody shop. Now I need to decide on what gas to buy. I have pure argon, but the consensus seems to be out there that a 2% CO2 mix works better. But then, is that still valid for a hobby welding using a simple short-arc GMAW?

Thanks for any advice,

Reno

By Lawrence (*****)

Date 07-01-2011 12:16

Welcome to the forum Reno!

I think you will be dissapointed with the results of short circuit GMAW on stainless with 2% Carbon dioxide. It's suits for spray transfer, but not so much for the lower energy short circuit mode.

A higher energy, 3 part mixture of He-90%, Ar-71/2%, and 21/2% carbon dioxide is common for short circuit welding 316 Lsi stainless steel.

By ssbn727 (*****)

Date 07-01-2011 15:32

Just to clarify Larry's excellent response and suggestion, he did not list 71 and a half percent of Argon or 21 and a half percent carbon dioxide...

He actually wrote seven and one half percent of argon, and two and one half percent CO2 just in case there is any confusion as to what he posted...

Btw Reno, "WELDCOME TO THE WORLD'S GREATEST WELDING FORUM!!! "

Finally, did you see how cool and calm French President Sarkozy was after he was attacked while greeting a crowd the other day??? He hardly missed a beat and continued as if nothing happened. :cool:

Respectfully,
Henry

By RenoHuskerDu Date 07-01-2011 21:06

I'm glad you clarified that, and thank you both for the welcome! 7.5% Argon and 2.5% CO2 make a lot more sense. Now I have to try to find that in this odd country were I live...I've lived in the US too, and found that everything about fixing stuff yourself is so much easier for you guys.

I was quite proud of our Sarko (his nickname) upon that jacket grab. He even refused to press charges against the perp, who apparently has a screw loose.

By RenoHuskerDu Date 07-08-2011 05:50

When I asked for that Tri-mix here in France all I got was blank stares. Even Aire Liquide said "huh?"

But I can get Noxalic 12 from them: 96% AR, 3% CO2, 1% H2. Has anybody used that? We're welding SS exhaust systems at our factory with Noxalic 12 and er307 wire, which works well, but would it work well for my 316lsi wire? Because we already have a contract for Noxalic 12, it would be easy for me to get a tank at home.

Thanks for any advice!

By Billyboy (*)

Date 07-08-2011 11:11

In our stainless room we have used both of these mixtures and I personally believe the 2% co2 will be easier to weld exhaust with. The Helium trimix had a more consentrated arc and blew through the thin walled exhaust terribly. I have mechanical comparisons of tensile strength, bend tests, and macro etch results of the two if you are interested. We are useing Miller axcess pulse welders so it won't really be apples to apples, but it might be somewhere to start. Another consideration is price. The 2% is pretty much free compared to trimix!! :grin:

By RenoHuskerDu Date 07-10-2011 15:40

Billyboy, which is the 2% CO2 you mention? I mean, what are the other gasses in it and in what percentages?

By fschweighardt (***)

Date 07-08-2011 12:02

They are going to have a tough time with a 90% He mix, He is way more expensive over there than over here. You might ask for some Arcal 11, which should be pretty good for your application

By RenoHuskerDu Date 07-10-2011 15:42

Would that be this Arcal 11?

>Arcal 11 = 75% Argon + 20% Hélium + 5% Hydrogène

I think I could get this one. Both Aire Liquide and CarboGas sell it here.

By fschweighardt (***)

Date 07-11-2011 01:20

thats the one

By DaveBoyer (*****)

Date 07-09-2011 04:12

Read this website, or at least the parts related to what You are doing:

http://weldreality.com/

He has strong opinions, but the experience to back them up.

By Billyboy (*)

Date 07-13-2011 15:27

Sorry for the delay in replying, the gas we currently use is 98% argon and 2% Co2.