Bodywork, Paint, Interior, Trim, & Wiring

discussions about bodywork, paint, interiors, trim, audio, electrical components, wiring, etc.

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1MGBV8
Paul Waters

(13 posts)

Registered:
10/24/2007 03:12PM

Main British Car:


TIG vs MIG for body work
Posted by: 1MGBV8
Date: November 30, 2007 01:04AM

I have a number of holes to fill in the body as I'm removing all the marker lights and gas fill pipe hole. I have been looking into welders and find that TIG is better for body work because of the lower heat but the cost is a bit high.
My neighbor has a wire-feed MIG welder I could use but am concerned that the higher heat my cause metal distoration. Does anybody have experience using a wirefeed welder for body work? Any suggestions on cheap TIG welders?


rficalora
Rob Ficalora
Willis, TX
(2642 posts)

Registered:
10/24/2007 02:46PM

Main British Car:
'76 MGB w/CB front, Sebring rear, early metal dash Ford 302

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Re: TIG vs MIG for body work
Posted by: rficalora
Date: November 30, 2007 10:24AM

Hi Paul,

I think most people use MIG for body work. It's true that TIG is lower heat (actually not sure it's lower, but it is more localized heat). The resulting weld is also more workable with hammer/dolly -- as I've read; I have not done TIG welding. But probably because TIG is way slower & way more expensive (the machine) MIG seems to be the predominant method. It takes some practice, but it's not that hard to get the hang of. If you or your buddy doesn't have an 'auto-dimming' helmet, get one. That will be the single best investment you make toward getting good welds. Harbor Freight & Northern tool sell them for about $50, sometimes less on sale.


V6 Midget
Bill Young
Kansas City, MO
(1337 posts)

Registered:
10/23/2007 09:23AM

Main British Car:
'73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep

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Re: TIG vs MIG for body work
Posted by: V6 Midget
Date: November 30, 2007 01:31PM

Paul, there really isn't such a thing as a good cheap TIG machine unless you happen to find a nice used unit. I bought a TIG welder off E-bay for about $250 and it did work, but it really isn't a quality piece compared to a good Lincoln or Miller machine. I later bought a Lincoln for about $2000 and love it. That's the price range where you'll get a unit you can truely use for all around work. MIG is fine for 90% of all the body work you'll have, just make short tack welds and let them cool then go back and tack between those and continue repeating until the seam is solid. There will be a little more finish grinding/sanding with MIG, but not too much. You can get a good MIG unit for hobby work for around $500 or less that will handle sheet metal work as well as heavier work up to around 3/8" material to make items around the shop. Go ahead and get the gas regulator and a bottle of Argon/CO2 mixture for mild steel and you'll be fine. I don't recommend the flux core wire and haven't heard anyone else have much good to say about it for auto work. The auto darkening helmet that Rob mentions is a great tool, a must have for the beginning or experienced welder in my opinion.
Depending on the point on the car I'm working on my choices for welding are usually MIG first, then TIG or Ox/Acetelene second. TIG isn't too good at bridging gaps, so making tack welds on patch panels is much easier and quicker with the MIG. I've used all three methods to finish weld these patches, depends on what the access is to a great extent and the width of any gaps. Unless the fit is very close TIG won't be of much use, so you'll wind up using the MIG or gas on those areas anyway.


MG four six eight
Bill Jacobson
Wa state
(299 posts)

Registered:
10/23/2007 02:15AM

Main British Car:
73 MGB Buick 215, Eaton/GM supercharger

Re: TIG vs MIG for body work
Posted by: MG four six eight
Date: November 30, 2007 10:50PM

I second the posts above. With a MIG welder use the smallest wire, that your machine will take, Then you can keep the amperage down for the sheet metal work.
I am a much better welder with an auto-darkening helmet!
A note about auto-darkening helmets. While I was building my V8 car, I had to go to the eye doctor to have some crud removed from my eye. The eye doctor asked if I had been welding, I said yeah, quite a bit, why? He told me that my eyes were slightly burn't, but should be fine. I had the shade set to dark and the speed set to fast. But since then, I trained myself to blink when I pull the trigger, to avoid the possiblity of getting a flash before the helmet darkens.

Bill


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5853 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

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Re: TIG vs MIG for body work
Posted by: BlownMGB-V8
Date: December 07, 2007 10:27AM

Good tip on blinking Bill, I hadn't thought of that. I've been toying with the idea of getting one of those cheap harbour freight wire feed units just to play with and see what it's good for. Waste of money you think?

Jim


danmas
Dan Masters
Alcoa, Tennessee
(575 posts)

Registered:
10/28/2007 12:11AM

Main British Car:
1974 MGBGT Ford 302

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Re: TIG vs MIG for body work
Posted by: danmas
Date: December 07, 2007 11:49AM

The first job I had after high school was to build a front end loader for a tractor, using pieces from two old truck frames the boss had. I would mark, cut and fit the pieces, and then a professioal welder would weld them up while I stood in the open garage door, looking out. I spent the next three days with my eyes bandaged and covered with salve from the flashing bouncing off the garage walls into my eyes. I can only imagine what damage would have been done if I had been standing inside the garage, merely looking the other way.

Welding is hazardous to the eyes, even if you are not the one doing the welding.

As for cheap wire feed welders, I would avoid them. I have one, and it is extremely aggravating. The problem with the cheap ones is the wire feed mechanism. Having the wire feed stop in the middle of a weld is a real pain.


rficalora
Rob Ficalora
Willis, TX
(2642 posts)

Registered:
10/24/2007 02:46PM

Main British Car:
'76 MGB w/CB front, Sebring rear, early metal dash Ford 302

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Re: TIG vs MIG for body work
Posted by: rficalora
Date: December 07, 2007 11:54AM

Jim, i have the this one & it's worked fine for me... I'd have loved to get one with more power selections than the 4 this has, but I can't complain about how well it's worked. I've used everything from .023 through .030 wire & haven't had any feed problems. I bought a refurb unit from HF -- i think i paid less than $200 if I recall. It's not a modern unit w/auto feed rate adjust or anything like that but works & will handle most any auto work you'd want to do w/MIG.

Forgot the link... [www.harborfreight.com]



Edited 1 time(s). Last edit at 12/07/2007 11:54AM by rficalora.



MG four six eight
Bill Jacobson
Wa state
(299 posts)

Registered:
10/23/2007 02:15AM

Main British Car:
73 MGB Buick 215, Eaton/GM supercharger

Re: TIG vs MIG for body work
Posted by: MG four six eight
Date: December 08, 2007 09:01PM

Jim
Not sure about the HF units, never used one. I have used Holbart, Miller, Dan-mig. One thing I've learned is, good welders, allow you to be a good welder. Then you spend less time grinding welds smooth!
I have a Holbart handler, and really like it. I've had it for approx 15 years. Used it for a couple of car restorations, built a snowmobile trailer, a tilt/sliding flat bed for a truck, lots misc projects, and my dad has borrowed it for a couple of car resto's. It's always worked like new. They run about $500-$600 I believe.
Which ever one you get, make sure it uses shield gas. Flux coated wire, is fine for thicker stuff, but tends to run to hot for smooth sheet metal use.

Bill


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5853 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: TIG vs MIG for body work
Posted by: BlownMGB-V8
Date: December 10, 2007 03:26PM

MG four six eight Wrote:
Flux coated wire, is fine for thicker stuff,
> but tends to run to hot for smooth sheet metal
> use.

I was wondering about that. I have an old Hobart 4 wheel wire feeder unit (used the big spools) that I can use whenever the time comes, and I have an argon setup for it that I'm going to be using with the tig once it's operational so it looks like all I need is the power unit and maybe some minor parts. I've found you can pick up surplus equipment from the local welding supplier and may go back there for the power unit. Probably makes a lot more sense than a disposable mig.

Jim


Keith
Keith Tanner
Grand Junction, Colorado
(92 posts)

Registered:
10/31/2008 01:45AM

Main British Car:
For the purpose of this forum, 1972 MGB GT 5.7l Chevrolet LS1

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Re: TIG vs MIG for body work
Posted by: Keith
Date: November 04, 2008 12:05PM

A caution about inexpensive auto-darkening helmets. I picked one up from Home Depot when I bought my welder (a tough little Lincoln 180T with gas). The response time of the helmet was awful and unadjustable. I'd get flashed every time. Needless to say, that helmet went back very quickly. I use a high-quality one now and I've never had any problems at all.


tr4long
Rob Furlong
Louisville, KY
(5 posts)

Registered:
08/20/2008 05:38PM

Main British Car:
1962 TR4

Re: TIG vs MIG for body work
Posted by: tr4long
Date: November 04, 2008 05:40PM

Skip the cheap junk from HF and save your pennies for a decent model from Miller, Lincoln or Hobart (which is the economy line of Miller).

All three sell a decent 110 volt MIG unit with gas regulator which will doe 95% of all the welding you will need to do. They run anywhere from $450 to $700.00 depending on where you live/features/etc. Home Depot and Lowe's both carry Lincoln 110 volt models that will suit your needs for a reasonable price

Flux core is junk for auto restoration. Flux core is pretty much junk for everything IMHO.

A spool of 70 series .023 wire will be fine for panel work. V6Midget's post is spot on. Use .035 wire for metals up to 3/16' thick. You can weld 1/4' with a 110 volt unit, but you won't get great weld penetration. I prefer to stick weld frame or suspension pieces or other critical components of this thickness.

There is a difference between the $50.00 HF helmet and the $250 Jackson unit, mostly reaction time and viewing area. That being said, I still use a cheapo.

"Welding flash" as it is known in the trade is caused by the UV from the arc rays burning little blisters on your eyeballs. Old school welders will tell you to put slices of a potato over each eyelid, as this will keep moisture on your eyes. It sounds weird but it works, sorta. Lubricating eye drops work well too.

It is usually the helper, not the welder who gets flashed. If he does it is usually from UV reflecting off an adjacent surface into the hood. A simple pair of clear safety glasses will usually block enough UV to keep you from getting flash. This is most important when someone is welding nearby.

Beyond that, it's all a matter of practice. Burn up a few spools of wire, experiment with the settings and you will be fine.

good luck.


tr4long
Rob Furlong
Louisville, KY
(5 posts)

Registered:
08/20/2008 05:38PM

Main British Car:
1962 TR4

Re: TIG vs MIG for body work
Posted by: tr4long
Date: November 04, 2008 05:43PM

Oh yeah, there's no such thing as an inexpensive TIG welder. There are cheap ones, though.


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