Welding new tailpipe on stainless steel exhaust backbox

[kevin316i]

There is a stainless steel sports exhaust on my iS, and I don't mind too much except for the 3" tailpipe
Is it feasible to get this cut off and a smaller one welded on? Would it be worth the trouble?

[DanThe]

Yeah, it doesnt matter if you use a mild steel tail pipe and standard non-stainless welding, the welder dont mind

[Hoggy]

Its a bit of a no no putting stainless to carbon as you get a situation called carbon pick-up which eventually makes the job a real untidy mess, bit like buying a new suit and putting dirty shoes on, much easier buying a stainless tailpipe and getting it tig welded on keeps the job a gud un,Boss

[DanThe]

How do you mean by "eventually makes the job untidy"?

Ive welded stainless onto mild with standard MIG gear plenty of times with no problems
Today at work infact

[kevin316i]

Thanks for the feedback. I thought that stainless steel welding requires special gear, so it would need to be taken off the car and brought to a professional to make up the new tailpipe and weld it into place.

I'm looking to buy a small arc welder to do a couple or small jobs on the car, but this couldn't be used on the stainless steel backbox?

[Turbo-Brown]

Generally speaking, MMA (arc) welders aren't all that suitable for work on car bodywork. Better off buying a MIG welder which are a bit easier to get half decent results with and reduce the likelyhood of blowing holes in everything.

Problem is that what seems like a good idea with a cheap MIG, soon turns into a nightmare as the wire feed goes tits up and the transformer overheats.

If you've got a lot of welding to do, get a fan cooled welder at the very least

Then there's the gas. Again if you've got a bit to do, set up an account with BOC and the costs will be a lot less than using the little bottles. Some people reduce costs even further by persueding their pub landlord to let them have some CO2!

[DanThe]

Ive looked into BOC before, you rent a bottle @ £150 per year and pay for the gas, depending on the mix generally around £12 for a bottle full.
Pretty cheap really

[charlE30]

I've also been thinking about buying some welding gear, would this be any good for jobs on my car like exhaust, engine mounts etc

http://www.machinemart.co.uk/product.as ... 2030&g=105

[DanThe]

The wire for non gas welders costs a lot more than standard wire, ive never used one but I doubt the weld would be as good as a standard MIG

[DanThe]

http://www.machinemart.co.uk/product.as ... 2029&g=105
This is good enough for light exhaust and panel welding with some 8mm wire and Argon/Co2 mix, just dont let it get too hot!

[charlE30]

The wire for non gas welders costs a lot more than standard wire, ive never used one but I doubt the weld would be as good as a standard MIG

Standard mild steel 5kg roll £8.95 + VAT, same as but for gaseless £36 + VAT I think I'll be using a little gas then, cheers Dan

When you say "light exhaust" what do you mean? I want to get something suitable for constructing a complete system.... after a lot of practice

[DanThe]

Sorry, "light use" I meant.
If your planning on doing a long run of weld on full power then like Turbo Brown said keep an eye on how hot the things getting

[TouringMatt]

I weld stainless all the time at home using a mig, stainless wire and argon mix gas, harder to weld than mild steel but still get good, strong joints

Matt

[Brianmoooore]

Then there's the gas. Again if you've got a bit to do, set up an account with BOC and the costs will be a lot less than using the little bottles. Some people reduce costs even further by persueding their pub landlord to let them have some CO2!

Or live next door to a "Paintball" site, like I do!

[e30bb]

I ve got gas less welder for sale if u want it?

http://www.e30zone.co.uk/modules.php?na ... 656#355656

[kevin316i]

Is a small arc welder a bad idea for welding thin sheet metals such as car panels? I just want something basic that will do the job. Thought a basic arc welder would be better than a cheap MIG?

[DanThe]

Arc welder is a big no-no for car body panels, you will end up with more holes than you started with!

[kam-325i]

Lets disspel some myths........

You can weld mild steel to stainless (lets say common 304)

To weld mild to stainless, this is what you need......

MIG: Stainless wire and a high mix of Argon gas.
MMA: Stainless or Disimilar rods.

If you use mild steel wire/rods to weld mild to stainless, the weld will fail, Fact.

The biggest problem with welding mild to stainless, more with thin stuff, is that Stainless has a higher melting point than mild, and stainless dose not "flow" as well as mild. You tend to blow holes in the mild before you can weld it to the stainless.

The best way is using TIG.