Thread: MIGs for car bodywork - do any go lower than 30A?

From memory, I think something that may fill your requirements would be a Cig Transmig 195 by now some 25 years or more in age.

The Transmig had a spot weld facility and had the capacity to weld with .6mm wire -with the necessary liners and contact tips.

Burn through due to initial amperage being too high, I believe is an incorrect assumption, having myself, welded up a good few vehicle panels with this size machine.

I would suggest that the wire stick out ,travel speed ,angle are far more important factors in the control of sheet burn through.


These machines come up for sale all the time and are are fairly well bullet proof and often some long overdue maintainence will have them working as new. Spare parts are still available as the wire feed design has changed little over the years.

But hey don't just take me word for it get on to one of the welding suppliers and check up on parts availability on N0.2 Tweco torches as this was the torch/gun these machines came equipped with.You will also need .6mm drive wheels.
These units come up all the time and will fall well under your budget and will will last a long time if you look after them.

Grahame

Its not so much the current but how you use the welder in my experience.

I use my welder on number 2 of 4 settings I very very rarely use the lowes power setting and my MIG is only 110 amps.

With very thin metals you dont run beads of weld but join up a series of small spot welds.

For example you tack in place your rust repair panel and you keep adding tack welds until it where you want it.

Now to join the individual tack welds together you need to put a hot weld next to a tack weld until the weld just wets the surface, pause, then repeat and slowly move along the weld seam. You will see each weld blend in with the previous weld and the surrounding metal. Do about 25mm at a time and always cool down with a wet rag or cloth.

That way you get flatter welds for less grinding and you don't put to much heat into everything.

As mentioned you will also need 0.6mm wire, dont bother attempting with anything thicker. I'll try and get a photo of a modification I did on a late model car where i cut out and welded in some 1mm zinc anneal steel onto less than 1mm car body/chassis material.

Cheers

Justin

Have you considered TIG instead? From your list of intended uses, it might suit you better.
One of the advantages of TIG for panel repair is that the welds are malleable, they won't crack like MIG welds when you get the hammer and dolly on to them.

They also have a very broad range of current settings, and as there's no wire size/speed limitations the same machine will weld coke cans or 1/2" plates together with just a change of settings.
To weld aluminium you just change to AC and swap tungstens - no spool guns, teflon liners or gas bottle swapping involved.

And for quick jobs or when you run out of gas, they double as a stick welder

Originally Posted by Grahame Collins

The Transmig had a spot weld facility and had the capacity to weld with .6mm wire -with the necessary liners and contact tips.

Burn through due to initial amperage being too high, I believe is an incorrect assumption, having myself, welded up a good few vehicle panels with this size machine.

Hmm.. I'd rather get something new with warranty at this stage - the flip side of that being I suppose that modern machines are made to tighter cost-efficiency tolerances and thus may not be engineered as well!

The Transmig 200 seems to be the modern equivalent to the 195 - has a 0.6mm roller available and the spot timer, although its lacking the burn-back control.

Originally Posted by Jarh73

Its not so much the current but how you use the welder in my experience.

I use my welder on number 2 of 4 settings I very very rarely use the lowes power setting and my MIG is only 110 amps.

With very thin metals you dont run beads of weld but join up a series of small spot welds.

For example you tack in place your rust repair panel and you keep adding tack welds until it where you want it.

Now to join the individual tack welds together you need to put a hot weld next to a tack weld until the weld just wets the surface, pause, then repeat and slowly move along the weld seam. You will see each weld blend in with the previous weld and the surrounding metal. Do about 25mm at a time and always cool down with a wet rag or cloth.

That way you get flatter welds for less grinding and you don't put to much heat into everything.

As mentioned you will also need 0.6mm wire, dont bother attempting with anything thicker. I'll try and get a photo of a modification I did on a late model car where i cut out and welded in some 1mm zinc anneal steel onto less than 1mm car body/chassis material.

Cheers

Justin

Thanks both of you - I'd been assuming I'd approach welding panels like I do welding steel bar, i.e. couple of tacks and then weld a bead. Sounds like for light panels taking more time, less heat, and lots of small welds will be the way to go.

Reading some of Graeme's older posts on deposition and wire speed, sounds like slowing down 0.6mm wire will push the heat transfer and current right down too, so 0.7mm steel may not be as impractical with a 30A minimum as I was expecting.

Time to go back and check my candidates for availability and support of 0.6mm wire, as well as work out the costs for aluminium setup (liner, U-rollers etc.)

Was just going to say TIG, myself. As festy said, reading your intended uses TIG stands right out as just what you need.

It will do mild, stainless and ally with only minor changes... MIG will need all sorts of setting up to swap between metals. TIG will also weld just about any metal that can be welded. It's also by far the best way of welding thin sheet... have a look on Youtube for the TIG trick of welding razor blades together... try doing that with a MIG

It's a tougher learning curve than MIG without doubt, but a good AccaDacca TIG is within budget and is probably the most versatile welding process of all.

I was watching Monster Garage the other night, and noticed that while they use a big old ESAB Mig on the structural, they pull out the TIG torch for bodywork.

So yeah, have a think about TIG > MIG.

Originally Posted by festy_

Have you considered TIG instead? From your list of intended uses, it might suit you better.
One of the advantages of TIG for panel repair is that the welds are malleable, they won't crack like MIG welds when you get the hammer and dolly on to them.

They also have a very broad range of current settings, and as there's no wire size/speed limitations the same machine will weld coke cans or 1/2" plates together with just a change of settings.
To weld aluminium you just change to AC and swap tungstens - no spool guns, teflon liners or gas bottle swapping involved.

And for quick jobs or when you run out of gas, they double as a stick welder

I was originally thinking about diving into TIG - I've had some TIG work done for custom bits for cars and it certainly looks beautiful. I was hoping to find a multi-process inverter unit that I could at least try TIG with stainless and mild steel just to get some experience - but it seems the inverter units don't have spot timers, and my immediate needs have to drive the purchase.

The amount of aluminium welding I'll do is tiny - limited to filling old bolt holes in a few panels - I can't justify the $$$ to get an AC-capable TIG so for now a MIG will meet my needs. If I find I'm welding more once I own a welder (likely ), I do want to give TIG a try, especially for more serious Aluminium work (engine manifolds etc.), in which case I'll maybe grab a used TIG machine in addition - I have 3-phase so it opens up some options on used machines from auctions.

Your point about welds cracking with MIG is a good one - I hadn't considered the properties of the weld itself from a bodywork perspective. Time to do more reading on it (well.. tonight at least. lunchtime's over).

Originally Posted by festy_

Have you considered TIG instead? From your list of intended uses, it might suit you better.
One of the advantages of TIG for panel repair is that the welds are malleable, they won't crack like MIG welds when you get the hammer and dolly on to them.

They also have a very broad range of current settings, and as there's no wire size/speed limitations the same machine will weld coke cans or 1/2" plates together with just a change of settings.
To weld aluminium you just change to AC and swap tungstens - no spool guns, teflon liners or gas bottle swapping involved.

And for quick jobs or when you run out of gas, they double as a stick welder

Only catch is the time it takes to learn. It does not take long to get quality work with a MIG plus its arguably better form non professional welders for any out of position welding. So much welding on vehicles is complicated and awkward in terms of position.

I have not personally had any issues with MIG welds cracking.

But its certainly worht looking at I have been umming and arring over an AC/DC TIG for ages.

Cheers

Justin

Lincoln Redi - Mig Remote 325amp | eBay

3-Phase beastie... more than you want to pay, admittedly, but amazingly good value.

Point of that one is, it's either 20 or 25A bottom range, according to a couple of differing sources on the net.

Seems the big beasts often have lower bottom ranges than the 'home' ones!

Hmm.. one of my replies went to moderation (the one to Graeme and Justin)? Possibly because I used multi-quote? Oh well, it'll appear in due course - I'm not ignoring you guys and thanks for the input.

The last two comments about TIG have me wondering again - I was put off TIG by the guy over the road from me (he works in construction and has a couple of MIGs and a TIG). When I was having a chat with him about usage he said definitely get a MIG if its my only welder.

Now I'm re-considering.. I have a question.

With TIG, how does it compare to MIG for things like welding a nut onto a sunken bolt shank?

As an example - I have a sheared water pump bolt to drill out on my current project car on stands in the garage, the bolt is horizontal, and sheared about 5mm below the surface of the (alloy) engine block. Last time this happened a mate popped over with his lightweight MIG and welded a nut to the shank by filling the hole - the nut, plus the huge amount of heat, meant the 10+ year old bolt unscrewed like a charm. Compared to making a drill guide and using left-handed drill bits, it was a piece of cake, and took a fraction of the time.

My impression of TIG is that its not as access-friendly and doesn't deal as well with welding up vertical seams or perpendicular to the horizontal?

Ok.. really have to get some work done.. thanks all!

Picture below shows how I would weld in a panel on thin metal. Each of those welds is basically joined up about 20 to 25mm at a time. Slowly work your way around until fully welded.

This was done on a snorkel install i did for a friend.



Cheers

Justin

Why not get one of those multifunction units? The Unimig 190 inverter does MIG & TIG, so you'd have access to both, and that's a $1,300 package from a place local to me in Perth.

I had a play with TIG at a short welding course I did just recently, and I _really_ enjoyed it. At first it was horrible, but after thirty minutes of persistence and thinking back to having watched a few TIG videos, I began to get quite good with it on the 1.6mm steel we were practising on. By the end of it, I was in love, and consider it to be a beautiful process.

From that experience alone, I'd much prefer to get a TIG for when I face the bodywork on my 4wd as opposed to using the MIG I currently have, or upgrading said MIG and doing a short bodywork course to get the confidence ready.

i think you would be fine with a kemmpi miniarc mig 150 should get a brand new on for $1500

Do you really, REALLY need a spot timer?

Can't help but think if you sat down with a big pile of scrap sheet offcuts and put some solid time into practicing spot weld timing and thin welds in general, it would pay off in improving your skills far better than relying on a timer.

That way, you could also look again at things like:

Tokentools inverter MIG TIG and ARC welder - MIG welding and TIG welding and ARC welding

MIG for general use, basic TIG for your finer work, plus a spool gun socket for ally work. That setup, including the spool gun and gas bottles would fall nicely under your budget, cover all your needs, and you'd have arc capability too.

I don't think you NEED a spot timer.

I'm confident enough to say that automotive welding like you want to do is 90% by feel.

After a while you get a feel for how thin metal behaves and you learn to put in just the right amount of heat for a given task.

I can place even welds one after another with each one looking just about exactly the same.

The other issue is that there are no "standard" welds when doing rust repairs each job is always different than the last.

More than happy to help out with any automotive welding advice.

Cheers

Justin