Andy1

I want to order mufflers and J bends for my LS1 914 conversion exhaust system (requires a very short run). The choice I have is between aluminized and non-aluminized (plain steel), but I have never welded aluminized steel with my TIG. I know the muffler shops use a MIG all day long and do kinda ok with it (adequate). I suspect I'll have to locally sand off the coating, but does anyone have any additional advice for TIG welding it? Gas? Filler rod? Tungsten? Technique?

Thanks,

Andy1

stealth71

iTrader: (15)

I would just use normal steel welding setup. That should work fine. Argon/C02 mix or pure Argon is fine. Red electrode. ER-70S-6 should probably be fine.

Haven't picked up the TIG in a while, but that's what I remember.

FirstGen

iTrader: (10)

Get the plain steel - uncoated if you can. aluminized does not weld well with TIG.

Use pure argon only. 75/25 will not work with TIG. Thorated tungsten is fine (red). Just use ER-70 like stated for filler. You will need to completly grind off the aluminized coating if you have that to get a nice weld. In this situation I would just MIG the exhaust. It's a pain to grind it all off...

cnichols

iTrader: (23)

I would seriously consider stainless, but if you're stuck on those two, stick with mild steel.

And, I agree w/ FirstGen...pure argon is what you want. But, if you should happen to change your mind and go with stainless, go to your local Airgas and get their Gold Gas called Stain Mix TIG...really brings out the color in the stainless compared to pure argon which leaves the weld grayish.

Andy1

Argon-check. Thoriated tungsten-Check. ER-70-Check. I don't have a MIG, so TIG is it. I'll just remove the aluminum as well as possible; both inside and outside within say 1/4" or so. I suspect the aluminum would instantly deposite itself to the tungsten if not removed.

Thanks,

Andy1

Andy1

Stainless would be nice, but I have to fabricate two large 1/2" thich flanges to couple up to my Z06 exhaust manifolds. Perhaps if I find some rem's of stainless plate at the local metal supplier, I might opt for that in the end. Stainless mufflers sure look pretty, don't they? Thanks for the tips.

Andy1

FirstGen

iTrader: (10)

I dis-agree. 100% argon should not leave the weld grey at all. This means you are using too much heat and/or you are not getting good gas coverage or flow rate...
The gold mix may have helium or some other inert gas mix to help with penetration but that's about it.

76LS1BIRD

iTrader: (35)

I used .5 steel for the 2 flanges & tiged the SS to it. Its worked for
3 + years now.

cnichols

iTrader: (23)

It has 2% Hydrogen, but I wasn't saying it was actually grey, but grey compared to the results when using the Stain Mix TIG. It's not because of the gas coverage or flow rate...those are both correct. It just really makes it look better. Don't knock it till you try it

RiceKilla

iTrader: (15)

From what I have heard form experienced welders aluminized gives off hazardous fumes so be cautious.

I am fabbing the exhaust on my Ls1 FC right now, using a lincoln 100, no problems at all.

The fun part's gonna be figuring out your angles and cuts.

FirstGen

iTrader: (10)

All I'm saying is that 100% pure argon will produce perfect welds with rainbow like colors with the right amount of heat, gas coverage, and flow rate.
If it is grey at all, you are either using too much heat and cooking the chromium out of it or there is not adaquate gas coverage or you have too much flow rate (especially when using a gas lens this will swirl oyxgen into the stream and contaminate it) or not enough.
There is no need for any mixed gases with TIG unless you are running out of amperage on the machine and need additional penetration.

Just my .02

Skele4door

iTrader: (1)

I haven't done any business with this company yet, but their pricing on stainless bends makes it almost pointless to buy aluminized or plain steel bends. They also have cheap aluminized bends as well if you decide to go that route. If you go aluminized you can also burn off the coating with a torch, but just be really careful because it emits caustic fumes like most other welding processes.

http://store.racing-solutions.org/index.html

Andy1

Can you give me some suggestions on welding dis-similar metals on the exhaust system; i.e. stainless to mild steel? What filler rod would you suggest?

Thanks,

Andy1

FirstGen

iTrader: (10)

309 is the correct rod for welding stainless to mild steel. However I would just use 308. 308 is a lot more common and the proper rod for welding 304 to 304. It is also the undergroud filler choice for most racers welding up chromoly or mild cages and other similar chassis componets because of its high ductile strength and resistance to cracking...

Andy1

I've got some 308 filler rod, but also suspected 309 was what is spec'd out for the application. With regard to your 308 filler rod for chromoly and mild steel comment, this is something I've never heard before. Do you have a reference to where I might find more information in this regard?

Thanks,

Andy1

FirstGen

iTrader: (10)

No I doubt that is published anywhere from a legality standpoint. I just mentioned that based on my experience from a top alchy funny car team I work on and other assorted credible sources that I won't be naming...

LS1Diva

iTrader: (3)

I've had great success using ER312 filler rod when TIG welding stainless to mild steel. You can also use this rod to weld dissimilar stainless like 409 to 304.