Best welder for Body Repair - Mig or Tig?

Hi Guys,

I am in need of some advice.

My mkII needs some rust repair done in the usual places - Heater bubble etc...

I need to get a welder and was speaking to my brother-in-law who suggested a TIG welder as they apparently are easier to use on thinner metal and give a better finish.

Most guys on the forum are using MIG's.

Any help is appreciated.

Cheers

Matt

mig is good for beginners

quote:

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Originally posted by esky79

tig is neater

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Without a doubt a TIG weld is prettier, but the joint needs to be spotless for a good weld.

I use and prefer a mig, you can use it to fill small gaps when the edges don't but up perfectly.

get both! You'll use em both, there handy and have a unique capability of their own.
Mig easy one hand operation, tig needs two hands and can do lots with ease, ie alloy, ss, steel, titanium, etc
Both of my welders owe me less than $1000 bucks total.

Its an old hobart, weighs a tonne, but does AC, DC- & DC+. I picked it up at auction. You can even get parts to fit from the states still. Bargain at $600. Inverters are getting cheaper, so might be worth the extra $.

I get almost perfect results every time irrelevent of the type of the repair by spotting with the MIG and quenching the weld area frequently so as to limit the heat soak along the panel.
The MIG heat soak is only for an instant for each spot when quenched using a damp/wet rag.
The MIG requires only one hand, the second hand is usually needed to hold something important. The mig spot weld is instantanous.
The negative side is that if ham fisted the operator can easily blow holes in the thin sheet metal.

Both TIG and oxy apply heaps of heat to the panel prior start of welding, which usually needs to be seam welded, which adds even more heat over a much longer period of time. Both tig and oxy always require two hands.

Maybe at your next lesson at the panel beating course you can ask the teacher exactly what the oxy and TIG heat does to the crystaline structure of motor vehicle sheet metal, especially in the zone immediately adjacent to the filler material and the parent material. Ask him also what are the ramifications of using oxy or TIG (ie heating in excess of 300 degrees Celcius) on the laminated high tensile steels new car bodyshells are manufactured from. If he is good he will be able to distinguish between the laminated high tensile steels used in the stressed chassis components such as chassis rails, as compared to the outer skins of the bodyshell.

The true test is to research exactly what processes the motor vehicle body manufacturers have used for the past 25 or so years: if they can't spot weld they usually MIG. I can't recall ever seeing a motor vehicle manufacturer using TIG or oxy on new body shells.

I agree with mig being the weapon of choice for sheetmetal. Unless you are a true craftsman trained years ago(if you were, you would us an oxy)mig is the easiest...the only disadvantage is that the weld is so much harder than the metal being welded, this can cause cracks if the metal needs to be worked after welding. It is a must as PeterM says, to quench the weld and do it in small spots...especially when welding sheet under 2mm in thickness. Oxy is the best for thin sheet but there are not many people who can control the torch properly and quench at the correct rate and location around the weld(hence needing to be a true craftsman)