The great welding method controversy

[MGBGT_noob]

Sorry if this opens up the proverbial can of worms, but I get the feeling I will with the question "what's the best way to weld?"

I've recently spoken to a fellow club member who believes that good ol' oxy-fuel welding can do as good a job, faster than MIG welding, on sheet metal. He said he took a course, based on techniques used in the aircraft industry. He said that using a properly set-up torch, you can seam weld down to 20-gauge steel, without warping.

Others have said that MIG welding is far superior.

Can someone give me an objective comparison of these techniques, not just "I always use XYZ, and it's the best".

 

[PAUL161]

It depends on your expertise as a welder and the type of welding job. Flat, round, stainless, mild steel,vertical, horizontal etc. Mig, I would say is the easiest compared to the oxy/acetylene method. Tig is a little harder, taking a steadier hand, but done by an expert, oxy/acetylene is my choice for thin metal and tubing. Such as aircraft tubing. Now, not meaning to, but is that confusing enough?

 

[V6MGB]

Yep totally agree with Paul's comments above. The person weilding the torch and stick is the prime decider on the quality of the welding.

Gas offers a few advantages in terms of additional flexibilty like low temp silver soldering and brazing , annealing , burning off some gasket materials , lead loading etc which you cannot do with a MIG set.

MIG is a commercial plus since the training time is shorter for a given standard.
The cost of MIG sets is getting cheaper by the day.
Some people (like me) find MIG torches easier to use since they are basically a one hand operation where as with TIG and Oxy / Acet you need one hand for the torch and one for the stick.

I also find MIG easier to use in confined spaces like building pedal boxes and under dash work.

Both are suitable for light gauge metals like car panels.

I personally think much depends on what you began with and what you feel comfortable using as much as anything else.

By the way for a definitive work on the subject get a copy of Ron Fournier's book Metal Fabricator's Handbook or the later edition by Ron and Sue Fournier.
This will cover everything you need for working on cars.

Cheers , Pete.

 

[dklawson]

I have done gas welding and TIG welding. There are times when each has its advantage. However, on larger sheet metal repairs, I'd TIG long before using gas. You have to heat the panel too long with gas which invites warping. With TIG you can tack the panel in place and then do short stitch welds to join the panels. While I don't MIG weld, by all accounts it is the easiest to learn and will be more than suitable for panel repairs. However, if the welds will be visible afterwards you will have some grinding to do.

 

[PAUL161]

Even though I'm old fashioned and have used gas for years, I agree with you Doug on Tig being a Little better than gas, to the point that I'm thinking of getting a Tig machine my self. I have a Mig machine and like it for getting into tight places. As Pete said, "one hand operation". Mig is very strong, but your right about having to grind down the the bead, even though it is very small.

 

[bill_young]

There are good and not so good points for all the methods mentioned, MIG, TIG, and Ox Acetylene. MIG has pretty much taken over the auto hobbiest market in the past few years due to the availability of inexpensive machines and the ease of beginner welders to make satisfactory welds with a minimum of practice. I think there is a place for all three in the shop, but if you have to make a choice for a single type I'd vote for the MIG unit because it's so easy to use and so versitile. Many of our replacement panels are installed with plug welds to duplicate the original factory resitance spot welds and for that there's nothing better than a MIG. And you can also make reasonable butt joints and fill holes, so all around it gets my vote. You can also crank up the amperage and weld heavier material so making tools for the shop such as rotisseries etc is a big plus over OxAcetylene.

 

[c5racer]

I prefer MIG over gas since I am an occasional welder. I can get in the groove quicker with the MIG. When I know gas is the better choice I generally break out some practice material of the same thickness to get back on the "stick".

Bruce

 

[MGZT260]

I have done gas welding and TIG welding. There are times when each has its advantage. However, on larger sheet metal repairs, I'd TIG long before using gas. You have to heat the panel too long with gas which invites warping. With TIG you can tack the panel in place and then do short stitch welds to join the panels. While I don't MIG weld, by all accounts it is the easiest to learn and will be more than suitable for panel repairs. However, if the welds will be visible afterwards you will have some grinding to do.

TIG is gas, don't confuse the guy before he starts. MIG can be gas or gasless. For less than virgin steel I would go with MIG over oxy. Heat buildup in the area being welded is less and will result in hopefully less warpage and even less chance of setting something on fire. But if using an oxy/acteylene torch for extra thin material teh best trick I've ever seen was to use black wire coathanger for the rod material instead of commercial sticks.

 

[bill_young]

TIG is indeed a process involving gas, an inert gas used as an oxygen shield and aids in cooling the electrode. The term "gas" as used previously I took as refering to OxAcetylene welding. TIG is a similar process but the heat there comes from electric current and not from the combustion of acetylene. TIG heats quicker and in a more concentrated area so is less prone to warpage. Of course a really good welder with any method will get superior results, and I've known guys that could work "magic" with a torch. MIG is also a gas process, that's the G in the name, but there the gas can come from either a seperate bottle supply or from a flux core in the welding wire which forms a gas when it's heated by the arc. The flux leaves a hard glass like residue on the weld which must be cleaned off before welding again in that area. It's similar to the flux used with "stick" welders. For general auto body use I don't advise considering using flux cored wire, get a bottle of CO2-Argon mixture and a regulator for your MIG unit.

 

[dklawson]

TIG is gas, don't confuse the guy before he starts.

For less than virgin steel I would go with MIG over oxy.

But if using an oxy/acteylene torch for extra thin material teh best trick I've ever seen was to use black wire coathanger for the rod material instead of commercial sticks.

I don't think MGBGT_noob or I are confused since in the first post he said: "<span style="font-style: italic">I've recently spoken to a fellow club member who believes that good ol' oxy-fuel welding can do as good a job, faster than MIG welding</span>"

I agree that most people I know who work on less than pristine panels say MIG is easier to get acceptable results with.

My father-in-law worked in a body shop during WWII. They routinely would scavenge coat hangers to use for filler rod with oxy-acetylene for panel repairs. For my panel work with TIG I used MIG wire as filler. It's easier to work with than filler rods which are typically 1/16" thick.

My experience echos Bill's comments on the localized heating and speed of TIG compared to gas. I also agree that for most repairs MIG will be the best choice. However, TIG is what I have at home so that is what I use.

 

[JamesWilson]

My experience echos Bill's comments on the localized heating and speed of TIG compared to gas. I also agree that for most repairs MIG will be the best choice. However, TIG is what I have at home so that is what I use.

I have and use all three, and a spot welder too, but I much prefer TIG over the MIG because it produced virtually no spatter and is a neat, clean weld.

 

[PAUL161]

[/quote] TIG is gas, don't confuse the guy before he starts. MIG can be gas or gasless. [/quote]

So no one is confused! For those who don't know, the gas used in TIG and MIG welding is an inert gas used for a blanket to keep impurities from the weld. It can be Argon or a combination of it and other gases. It does not burn!
In my opinion, MIG welding with out gas, (using a flux wire), does not give a smooth weld as using solid wire and a blanket.
Also, debated quite a lot, acetylene welding is as strong as other methods depending on the type of filler used and penetration. Control of heat depends on tip size and flame. Aircraft tubing has been welded for years with acetylene, with perfect results I might add.
As previously stated, MIG welding has taken over the commercial industry. Mainly due to it's cost, automation, simplicity and speed.

 

[MGBGT_noob]

TIG is gas, don't confuse the guy before he starts. MIG can be gas or gasless. For less than virgin steel I would go with MIG over oxy. Heat buildup in the area being welded is less and will result in hopefully less warpage and even less chance of setting something on fire. But if using an oxy/acteylene torch for extra thin material teh best trick I've ever seen was to use black wire coathanger for the rod material instead of commercial sticks.

No fears ZT. I know the difference between the various welding processes fairly well.

I know that "gas" welding is usually shorthand for oxy-acetylene (or similar processes using Propane, Hydrogen, or MAPP for fuel), even though MIG and TIG use some form of gas as well.

I know that "arc" refers to fluxed rod welding, even though the MIG and TIG processes involve an electric arc.

I'm just looking for a comparison of the various methods, and their relative suitability for body work.