Newbie: Exhaust Fabrication using a MIG?

[youngm]

Hi all,

I'm planning on investing in a light duty MIG Welder for fabricating my own exhaust system and intercooler charge air intake pipes etc.

I'm totally new to welding, however, I'm a quick learner and determined to teach myself by investing a lot of time reading and practising before I attempt the fabrication on my own car.

My first project will be a custom exhaust for a twin turbo application on a horizontally opposed 6cyl (911 Turbo motor).

I'm researching different types of MIGs for this application and am wondering if you more experienced welders can give me some advice and direction. I was looking at a gas/gasless MIG, anywhere between 135A to 170A with as many adjustments as possible within my budget. I'm a total newbie, so I don't want to spend a lot of money *yet* on a high-end MIG welder. My budget is around the $700-$1k mark.

The exhaust system will be fabricated in mild or stainless steel.. probably mild initially so I get practise and proper fitment. When it eventually ends up rusting, I'll then re-fabricate it with stainless steel after getting more experience.

Am I looking at the right type of MIG for this application, or should I look at an even lower powered unit, such as a 100A unit? I intend to do it with gas for better/cleaner welds and will tack it all up on the car first for proper fitment before attempting the final weld.

Attached are some pics of a very similar exhaust system to what I'm contemplating for my car.

Any advice would be greatly appreciated. I'm really excited to delve into the world of fabrication, even though I'm employed in the I.T Security arena.

Thanks in advance

[aametalmaster]

If it was me i would go with a MM180 and the gas so you can do nice work...Bob

[youngm]

Thanks, Bob, for your speedy reply.

I was looking at the MM180.. looks like an impressive entry level system.

Curious, is the 180A a bit of overkill for exhaust work and light aluminium work? That's all I can envisage myself using it for.

Would a MM 140A (with AutoSet) be a more suitable unit for light exhaust work? I like the AutoSet feature, especially considering I'm an amateur

BTW, we run 240v power outlets here in Australia.

[Aerometalworker]

Thanks, Bob, for your speedy reply.

I was looking at the MM180.. looks like an impressive entry level system.

Curious, is the 180A a bit of overkill for exhaust work and light aluminium work? That's all I can envisage myself using it for.

Would a MM 140A (with AutoSet) be a more suitable unit for light exhaust work? I like the AutoSet feature, especially considering I'm an amateur

BTW, we run 240v power outlets here in Australia.

Just a quick question, why are you so set on MIG? The thinner aluminum found in your intercoolers can be a real challenge with that process. That and you would probably want a spool gun to go along with it for aluminum. If you do stainless you need a different gas then steel, same with aluminum. 3 bottles of gas can end up being pricey.

I see 2 directions you may want to consider:

1-Nice OA setup with a light torch and hose, and a good selection of tips. With the right filler and flux you can weld any weldable material except titanium, plus heat, braze, solder, cut steel, etc.

2-Used TIG setup, can be had for under 1k normally and probably better suited for what your doing then a MIG.

I firmly believe OA welding is what should be learned proficiently before any other welding process as it teaches all the skills of welding, warpage, etc. That and seeing as how its invaluable to a fabbing shop, should be first on the list of welding tools.

-Aaron

[youngm]

Hi Aaron,

I was pretty much set on a MIG because I've read it's the easiest to learn and can get me up and welding decently in the shortest time frame.

I've read TIG is the hardest to learn and requires significant practise and experience?

I'll look into the OA process too. Thanks for the tip

[Aerometalworker]

Hi Aaron,

I was pretty much set on a MIG because I've read it's the easiest to learn and can get me up and welding decently in the shortest time frame.

I've read TIG is the hardest to learn and requires significant practise and experience?

I'll look into the OA process too. Thanks for the tip

Well id say OA is the hardest to learn....but MIG is the hardest to do WELL.
I think since MIG seems easy to do...its percieved as EASY...id have to argue. When doing a lot of one-off type parts its difficult without a lot of experience to do it well. Do you have any tech schools around you with a welding program at all? I think getting some hands on teaching from someone would be a great help to you.
-Aaron

[youngm]

Aaron, I didn't mention it in my original post, however, I am definitely looking into enrolling into a short tech course in the new year. There really is no substitute for hands-on training, so that's a definite must.

[phaxtris]

your best bet is a mm180 or lincoln equivelent, it is overkill for exhaust, but will give you enough power for other automotive projects. what your talking about is what i do on the side, over this past summer i have probably done 15 sets of intercooler and exhaust's

the aluminum sold on ebay and the like for aluminum intercooler piping is far to thin for mig welding, for your first go my suggestion is to use aluminized mandrel bends from a supplier such as walker auto parts (for intercooler and exhaust pipes), the aluminized pipe takes a very long time to rust, systems i did 5 years ago on summer cars look just as good as the day they were made, just a little dirty

[Glenn B]

MM180 With AutoSet

If you want the auto set. Miller will be adding it to the MM180s soon if it is not already out. You may want to ask your local Supplier.

[youngm]

your best bet is a mm180 or lincoln equivelent, it is overkill for exhaust, but will give you enough power for other automotive projects.

Thanks for the input

When you say the 180 is overkill for exhaust work, what kind of amperage rating should I look for in a MIG for exhaust work then? Is 130-140A enough for this kind of work, since it's not very thick metal?

I plan to build my exhaust using mild steel first and then maybe duplicate it in T304 SS further down the track as I get more proficient and confident at welding.

I think maybe even a ~100A unit should suffice for exhaust fabrication, but want clarification from you more experienced guys

[Portable Welder]

I own several mig welding machines and also a high end tig unit, when it comes to doing thin exhaust work I have a miller mm135 115Volt machine, this size machine works great up to 1/8" material, as far as being able to do mig aluminum with it you may be a little disapointed.

You would be fine for the stainless and mild steel however.

The guys recommending the next size up are just trying to give you the ability to do a little more than you need for exhaust because when working on cars it wont take long before you out grow the 115V model, say you want to attach a bracket to the frame to suspend the exhaust off of, now your at the outer limits of the 115V model and just perfect for the MM180.

I personally think you should wait to buy your machine untill you've been enrolled in the class for a while and can try different machines so you can see what we all are talking about.

Keep in mind, if you buy a quality machine and decide you get bored with welding than it will be a lot easier to resell a quality machine verses a genaric machine.

I've had mig machines that I bought for $ 1,500.00, used in my welding shop on a daily basis for 10 years and still have no problem selling them for
$800.00 10 years later.

[youngm]

Thanks for the tips. Great forum!

I think you're probably right. Once I get my exhaust work all completed, I'll probably look at fabricating a solid workbench for my garage which will use thicker guage metals, so it's probably worth investing a few hundred more and getting the MM180 unit.

I guess fine adjustability of output power is a key factor too, especially when looking at working on a variety of guage metals?

[burninbriar]

I think you're probably right. Once I get my exhaust work all completed, I'll probably look at fabricating a solid workbench for my garage which will use thicker guage metals, so it's probably worth investing a few hundred more and getting the MM180 unit.

If this one exhaust system is all you will do then you would be way ahead of the game to pay for someone to do it.
If you like playing in the shop, then you should get something that will handle all you're future needs, if the 180 will do it, fine, but don't cut yourself short on capability. Its always better to have a little more you don't need than to not have enough. If you don't have enough, you might as well have nothing at all.
I hope that came out right.

[Carl W.]

I may be off base here but recall that Millers inductive 210 was being phased out this year going for electronic chopper control with the 210 units. They are both good units, the 210 inductive may phase out cheaply.
Take a look at these lower amp units like the 180 and 140 machines, look at the duty cycle they have it drops to 30%, something to be aware of.
Good training is better than old bad welding habits to break.
Over all I say the 180 Tig would be better for your needs.

[Danny]

BTW, we run 240v power outlets here in Australia.

MM 140 is a 120V unit. MM 180 is a 240V unit.