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MG MGB GT V8 Factory Originals Technical - Welding

Hey all,

With all the cuting and welding required for these projects, I was wondering which sort of welding equipment is used/preferred. ie MIG, CIG, oxy etc

I haven't welded before, so I'd like to know which one would be the best to use/learn.

Cheers, Stuart.

Stuart Overell

a 125 volt mig welder will work fine for most parts on an MGB. It's the easiest to learn, less expensive than tig, and you don't have an open flame from a torch. Each welding technique has its place and strengths, but I vote for mig for it's cost, versitility and easy learing curve.
joaquin

I bought a little Lincoln wire feed. I'm real impressed by it. I do eventually want to convert it to gas. It's easy to weld with and I'm having a ball with it!
JWK Kerr

Thanks for your tips. I might hunt around for a second hand MIG. Though, in what situation would one use a TIG over a MIG?
Stuart.
Stuart Overell

Stuart,
Some feel that a TIG unit gives a better looking weld over a MIG, and maybe better penetration. Of course, the operator has to be proficient in the technique. Joe
Joe Ullman

TIG is similiar to oxy-gas in that you are using the heat from a torch to melt the parent metal then adding your consumable rod, or, if the material is comaptible, you can autogeneously weld (fancy name for use no filler rod)

MIG uses the heat from the electrode wire to melt the parent metal, which is how it is possible to make a good LOOKING weld with absolutely no penetration or strength.

A properly configured MIG system can weld steel, aluminum, and stainless. Note that aluminum will require quite a bit of horsepower on any significant section because aluminum wicks the heat away from the joint much faster than steels.

Most inexpensive TIG system are DC and cannot weld aluminum (which requires AC)
Greg Fast

You have more control over heat with a tig. You can weld together different thickness metals with tig more easily than a mig as the mig will have a tendacy to burn the thinner gauge metal first. I use tig on critical joints and exposed welds that need a "professional" appearance.
Joaquin

For what you are talking about, the cost of a MIG is better.
If you are an expert gas welder, a TIG is a snap! TIG is very expensive, I own one only because I use it professionally. You can weld tin foil together with a TIG, a MIG (wire feed welder) has limits in what it can weld and is less forgiving.
A tig does not produce as mush dissipated heat and therefore will warp less of the sheetmetal. Its also (I think) easier to butt weld two panels together and make them look just like new with the TIG.

After saying all this, for a one project welder, and for industrial shelving that you will build in your shop afterwards, the MIG is the way to go...
If you plan to spend five times as much, go with the TIG.

-BMC.
BMC Brian McCullough

Considering the above, does the use of MIG or TIG have an effect on the strength of the welds? Is one stronger? or does it come down to the person welding? Otherwise, is it just the finish which makes the difference?
Stuart Overell

With proper joint preparation, and selecting appropriate wire speeds and voltages, a MIG will supply a joint as strong as the parent metal. The filler metal will typically be harder than TIG filler wire.

Selection of filler wires can affect the uktimate strangth of the weld joint.

MIG tends to be forgiving with less experienced welders, but has limitations listed above.

The only downside to MIG is that you can make a good appearing weld that has no penetraion and low strength. If in doubt, set up the welder and prin a practivce joint, cut it apart and confirm the joint is good
Greg Fast

Greg Fast wrote:

"The only downside to MIG is that you can make a good appearing weld that has no penetration and low strength."

This can't be stated often enough! I have seen MIG welds that looked picture perfect, but could be pulled apart by hand. The beauty of MIG welding is it's ease of use - with a little bit of practice, anyone can lay down a good bead. That is also the down side of MIG. It is so easy it can be deceptive. I would advise anyone NOT to use a MIG welder for structural welds until they have verified that they are doing it correctly.

It is also possible to make a pretty but poor weld with any of the other types of welders, but the practice needed to make a pretty bead also teaches you how to avoid that. Usually.

In general, TIG welding (or gas) is preferable to MIG for body panels if you are doing hammer welding. As Dean said,the MIG bead is a bit harder than the others, so it is harder to get a good hammer weld with it. Since very few people do hammer welding, that should not be a problem. On the other hand, if you are going to be doing body work, hammer welding is a good technique to learn
Dan Masters

Regardless of your choice of welder- MIG was mine- spend the $100-150.00 & buy an auto darkening helmet instead of using the flip down that comes with many setups.

A pro uses a flip down without thinking, because he has been doing it for years, but for a beginner, the auto darkening helmet eliminates one of the major problems in learning to weld.

But the way, the pros in my company who spend all day at a welding table have both switched to self darking helmets & would nevewr go back to the old way.
Jim Stuart

This thread was discussed between 02/10/2003 and 10/10/2003

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