[kaboom10]

The twin turbo install I am doing requires a lot of exhaust fabricating. I have a Lincoln 180C mig and it can be used with or without flux core. Is there a stainless steel flux wire? Can I use a thin steel welding wire on stainless steel? What gas mix should I use.

[AKweldshop]

Should use 308 stainless wire, as most header piping is 304.
Here's some wire I've used.
http://www.ebay.com/itm/Stainless-Steel ... 4accc87380


Trimix gas.

90% Helium, 7.5% Argon, and 2.5% co2.

Should be able to get a smaller bottle, 84cuft to 125cuft.... If your LWS will work with you.
Its a sound investment if you plan on doing a fair bit of that type of work.

Now,
I've never used stainless "flux-cored" mig wire.
Can't speak to it, can't recommend it, or nothing.
All I'm saying is that its out there.
Might be worth looking into, if your not worried about uglier welds.
Here's the link.
http://www.ebay.com/itm/035-308L-FCO-Ga ... 2eb897979c



2cents,
And someone with more experience will chime in, I'm sure....

~John

[coldman]

Stainless flux core still requires gas shield. So why not use solid wire and good old pure argon for less cost and toxicity.

[AKweldshop]

coldman,

My link was gasless.
http://www.ebay.com/itm/035-308L-FCO-Ga ... 2eb897979c

Are you referring to plain 308 mig wire with 100% argon???

Or tig???

~John

[coldman]

Sorry John, I had not checked out your link when I made my post. Last time I checked my LWS (it's been a while) s/s gasless mig wire was not available (either not invented yet or maybe not made it to the backwoods (Oz) yet ...

Here is a link to a local solid wire that recommends Argon with either 1-3% O2 or a small percentage of CO2.

http://apac.thermadyne.com/IM-Uploads/D ... 316LSi.pdf

I have used the 308 wire with pure argon and I am told it is good for up to 16 gauge. I had no issues with it same as others I know that have used it the same way.

Since the application is exhausts, I don't see why pure can't be used. I say this only because I know small percentage mixtures are not common in the States.

Anyone care to chime in on this one?

[AKweldshop]

No problem man, I read your link....

Might be good for the OP to try and get some of that wire.

Might make it better than trimix.

But,
I cant speak to it.

~John

[Bill Beauregard]

Migging beer kegs we used solid wire, 90/7.5/2.5 gas, used less than perfect back purge technique with steel mix, It was functional, but the backside wasn't as pretty as I would have liked. I would like to try the mud for the backside.

[Superiorwelding]

The twin turbo install I am doing requires a lot of exhaust fabricating. I have a Lincoln 180C mig and it can be used with or without flux core. Is there a stainless steel flux wire? Can I use a thin steel welding wire on stainless steel? What gas mix should I use.

Kaboom10,
I have to first ask, respectfully, if you know exactly what you are getting into? Fabricating custom SS headers is not for the faint of heart. There will be angles and bends you never dreamed of. Again no offence but I want you to be aware of what you are about to begin.
With that said, the Mig process will require some skill and setting your machine very well, to do you any good. It will be very easy, depending on wall thickness, to blow through and get sugaring on the back side, even with a purge if you blow through. A back purge is a must in any header application. MIG can be done however and I would recommend 308/308L .023/.030 wire. Wire grade will depend on the substrates composition.
Use only the Trimix 90% Helium, 7.5% Argon, and 2.5% co2. Using any mixture with more than 2.5-3% oxygen will cause oxidation and your welds will rust. When you go for your gas make sure they don't give you the Oxygen trimix. One thing to keep in mind if you choose to MIG your headers, your gas will be very expensive and will not last very long at all. If memory serves me correct, I believe it is 35ish CFH for the trimix and you will want to make sure you set your post-flow 7-10 seconds, to protect the weld. Inside you can use 100% Argon or piggyback off the trimix if you have to. 15CFH should do for purging.
Personally, I do not feel MIG would be the correct choice for your application, although TIG has its negatives as well.
I did see you posted in the TIG section and will try to get over there as well.
-Jonathan

[greenteagod]

I'm also looking at doing this. Nothing as complex as custom built headers, but I have a Hobart Handler 190 and am needing to run a new exhaust for my little civic. Was wanting to do it stainless to have it be something I'd only have to do once, but it sounds like getting good results with stainless exhaust and mig might be a bit advanced for my hobbiest skill set.

Would love to get a tig set up, just no money for it.

One thing I was wondering here. My idea was to do mine with V band clamps. The flange fits over the pipe itself So it wouldn't be welding end to end. For a setup like that you wouldn't need to do an internal purge I wouldn't think. And the weld itself would be a touch more forgiving as you'd have the flange soaking up some of that heat so you wouldn't risk blowing through as much as if it were just end to end pipe right?

I have very little experience with that so forgive me if my assumptions are totally off base.

[Otto Nobedder]

greenteagod,

Yes, the lap-joint of slip-flanged connections will make welding much easier on thin material, but you'll still want either a back-purge or flux, because on thin-wall, the weld heat alone will cause sugaring, defeating part of the purpose of the lap-joint flanges.

308 wire can be welded with 75/25, though it requires more heat than recommended, and the surface will be unattractive. Pure Argon is terrible (at least in 11 ga... A helper accidentally hooked up the wrong bottle). I can't speak to the argon mixes with small amounts of O2 or CO2 from experience.

Tri-mix (90he, 7.5ar, 2.5co2) is the gas of choice for MIG stainless in my opinion, but for the back-purge, nitrogen is dirt-cheap compared to argon, and for an exhaust system is more than adequate.

two cents..

Steve S

[Oscar]

I'm also looking at doing this. Nothing as complex as custom built headers, but I have a Hobart Handler 190 and am needing to run a new exhaust for my little civic. Was wanting to do it stainless to have it be something I'd only have to do once, but it sounds like getting good results with stainless exhaust and mig might be a bit advanced for my hobbiest skill set.

Would love to get a tig set up, just no money for it.

One thing I was wondering here. My idea was to do mine with V band clamps. The flange fits over the pipe itself So it wouldn't be welding end to end. For a setup like that you wouldn't need to do an internal purge I wouldn't think. And the weld itself would be a touch more forgiving as you'd have the flange soaking up some of that heat so you wouldn't risk blowing through as much as if it were just end to end pipe right?

I have very little experience with that so forgive me if my assumptions are totally off base.

Now a days there are lots of options for getting a decent tig rig going. Granted you'll have to settle for a chicom welder, but nothing wrong with those for hobbyist use. All you need is one with A. a foot-pedal and B. Some kind of post-flow adjustment. Don't bother looking for one with AC-capability if you are only going to be working on steels. You can use an HTP dual-flowmeter regulator to run a purge off of one argon bottle, or get a small 1-lbs can of SolarfluxB from weldingsupply.com for $38. With this you can skip the purge and prevent the back-side from sugaring by applying this flux. Makes things a heck of a lot less complicated.

[rake]

98-2 Ar-CO2 (known as stainmix by some suppliers) also works at a lower cost than Trimix.
308 for filler on tube to tube but, if you are unsure of the composition of flanges, bungs, fittings, etc.
then 309 can be a Godsend on those components. 309 is like the napalm of SS filler. The shit sticks
to about anything! Really great for dis-similar metals.

Post some pics when you're done. Well done exhaust can be a work of art sometimes!