Mig or Tig welder...

[dumb person]

Originally Posted by RockHillWill

but I would sure consider the GAS Welding method if you have the opportunity. It is also,by far, the least expensive.

Not in my country, there is a shop with gas but they charge $5 a minute to use it.
For what it is worth i used a gasless MIG with lots of flux splatter. Lots.
(So how does a TIG work on uncleaned rusty metal? Really poorly i guess?)

[RockHillWill]

Mr. 'Person"...

I did not state that very clearly. I meant to say that it seems to be the less costly of the welding options when it comes to purchasing the equipment.

Vince: Well stated. I understand your position quite well. I also like to see how other folks do things. I am not at all afraid to buy a tool or a piece of equipment, and that has quickly taught me that talent, not tools provides the best results. Unfortunately, I have also learned that I have more tools than talent. I am particularly having a hard time learning to gas weld in a proficient and productive manner. I quit building race cars when my eyesight went downhill, but I have a new sheetmetal project that will require gas welding aluminum panels, so I better get something figured out.

[d.j. moordigian]

Originally Posted by RockHillWill

I am not at all afraid to buy a tool or a piece of equipment, and that has quickly taught me that talent, not tools provides the best results. Unfortunately, I have also learned that I have more tools than talent. I am particularly having a hard time learning to gas weld in a proficient and productive manner.

Will,

Nahhh.....your talented, and tools help the talent. I've seen posts of your
build! Sometimes, with a lack of tools, but talent, results in,.." necessity is the Mother of butchery "...

*Look for the special lens for gas welding Aluminum(I think it's Cobalt Blue)*

[Steve Wastler]

I have had very little exposure to welding, have recently had the want to teach myself, this is a great thread. Thanks for all the views and opinions!!

Flop you are truly a metal master!!!!

[Terry, NJ]

I have often speculated on what you're saying about the HAZ. Hammer welding, I was afraid would just make the metal more brittle. But then aren't you actually forging it which will toughen it? I never did resolve this in my mind. However, wouldn't the metal (weld & Parent) benefit from a little preheating or annealing?
Terry

Originally Posted by RockHillWill

I have no intention of stirring up the pot from a technical standpoint, only that I have been doing a lot of studying lately regarding this TIG vs MIG vs Gas welding, and have the following OPINION (only!).

It is my 25 year personal experience that MIG welding on sheet metal, while done as nice as any of the methods has the greater tendency to crack from vibration. I used to build race cars, and no matter the way it was welded and by whom, it would ALWAYS crack somewhere to some degree after each race. No problems with the structural items that were MIG welded.

I have interviewed very knowledgeable folks from one end of the country to the other for an answer to this issue. They did not all agree, but all were happy to express THEIR perspective. TIG welding is much more forgiveable as regards sheet metal resistance to cracking, but the best that I have experienced personnaly is the gas welding. I am very good friends with a gentleman that has gas welded aluminum race car bodies for 42 years, and it is his opinion that gas welding is the better choice for welding sheet metal if your intention is to use it in a vibrating envirinment.

It is our opinion that this tendency to resist cracking is due to the fact that gas welding forms / allows a more ductile weld. I understand that filler material has an effect on this issue, but i believe it is not the predominant factor.

What I have formed as an OPINION at this point is that the slower rate of the gas welding and the lower pressure afforded by the HENROB style totches allows/permits the nearby metal metal to spread the heat over a larger are adjacent to the weld (HAV= heat affected zone / blue area). This slower heat migration expands the metal while hot, but shrinks back beyond its original position. This is why you 'hammer weld'. You are stretching the metal back to it's original thickness.

You can confirm this on your own by only looking at the HAZ width with the different types of welding. The wider HAV is happening because the gas welding is slower to cool resulting in maintenance of the metals ductility and resistance to cracking. You can get furthur input if you use a Rockwell hardness tester to review the metals hardness (tendency to crack) near to the welded area.

So, it is only my OPINION, that you can get suitable welds with any type of welding process, but if you are welding something that is in a vibratory invironment (race car, Model A, etc) that is used over a long period of time, you would be wise to consider a method that maintains the metals original ductility. MIG and TIG are great, rapid welding proceedures, but I would sure consider the GAS Welding method if you have the opportunity. It is also,by far, the least expensive.

[RockHillWill]

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Terry, I have similar thoughts as yours and have resolved it in my mind as follows:

When you weld there is heat and it causes expansion of the metal (which makes sense to me), and the metal becomes thinner, but when it cools, it shrinks back past the point of its original position (I do NOT understand that!), but it makes the metal thicker in that area. When you hit that area with a hammer it stretches / thins the metal back to its original thickness.

To make this more clear try this: Take a piece of sheetmetal 12" x 12" and shear it in half resulting in two pieces 6" x 12". Lay them side by side, clamp them both down, then weld a small tack at one end of the 'joint' seam. Let it cool, then unclamp and the two pieces of metal will be be laying next to each other and be parrallel over the length of the panels. Now, place another tack at a position about one inch from the original tack. What you will see as the heat dissipates, is that the far end of the panels, they will spread apart. Do nothing, but let them cool down and before long the far ends of the panels will shink back as they cool to the point that they will overlap! Then using a hammer and dolly, hit the second tack until the far ends are again parrallel. This will maintain the metals thickness and alignment, but I agree with you that it may slightly 'harden' the metal at the tack area. But this exposes what I think is the trick/advantage of correct hammer welding. With experience you learn to do the 'hammer' part while the metal is still warm/hot, giving it time to anneal as it cools.

I have recently designed and built a moderate sized power hammer and a custom English wheel and in discussing wheels and dies with experienced suppliers, they all cautioned me about running metal panels thru their dies and/or wheels that have been MIG welded. They have told me, that even with hardened tooling it 'marks' their wheels and dies, and are so convinced of that, they warm you before purchasing. I ruined one of the lower anvil wheels on my new English wheel, so I believe them as well! I have formed the opinion that for whatever reason, MIG in particular results in a much harder, faster cooled weld and that that results in a brittle area just adjacent to the weld. That is where all the breakage occured in the race car environment.

Again, it's just my OPINION, that if you are just welding to join something together, MIG is one option, TIG is perhaps a better option for sheet metal, but if you are going to do any panel 'shaping' subsequent to welding, gas (hammer)/welding is much prefered, as it maintains both the metals thickness and approximate ductility and malleability. All of this is also influenced by filler material and resulting 'puddle' chemistry.

Your thoughts?

Anybodies thoughts? I'm still learning this 'stuff'.

[PetesPonies]

The weld is influenced by the filler material. But just as you can easily var that with a TIG process, you can also with a MIG. There are different wires that can be used. You can use a much softer wire than "normal" MIG wire. That will leave a softer bead, more easy to finish and work.

[George Miller]

Originally Posted by fordgarage

I once knew a guy who could restore a car with essentially a screw driver, a pair of pliers, and a claw hammer, while working on his back on a gravel driveway.

I like learning about what other people do, how they do it, what tools they use and why, and seeing the results they get.

I am primarily self taught, big on finding the 'best' tools for a job, and acquiring and using them as best as my abilities allow.

I have never claimed to be a professional or an expert, or any better than the guy I referenced above.
But I do have strong views and preferences.

Tools don't make the man. (though they may help)
The man is made by his ability to best select from and use the tools available to him.

So I would not say or assume something could not be done.

Vince You are right on.

[Terry, NJ]

Will, To see that shrinkage really well. Try it with Stainless! S.S. pulls a lot harder than CRS or HRS. I get it! I can't figure out that shrinkage question either (Why it shrinks or contracts more than it's original size) Now, I've heard a lot of talk about "Fillers". What exactly are they? Is this the normal body fillers or is this some metallic overlay that you put on with heat?
Some of the work pictured here (Patches) seem like the work I do with my MIG. I can't see an appreciable difference. I always butt weld the patches in and with many many tacks that give penetration through with something to grind on the opposite side. Occasionally, I have to fill a hole that is too small for a plug so I start on one side of the hole and work across leaving a final gap to be filled after everything's cooled down a while. This results in the smallest possible amount of weld to shrink. The shortest "Bridge" that will be shrinking and there by causing the least distortion of the parent metal. Another Technique I learned from from a professional restoration shop is, always use round or rounded patches. Sharp cornered rectangle patches pull more than rounded ones. For the large holes, I use the knock outs from electrical boxes.
Terry

Originally Posted by RockHillWill

Terry, I have similar thoughts as yours and have resolved it in my mind as follows:

When you weld there is heat and it causes expansion of the metal (which makes sense to me), and the metal becomes thinner, but when it cools, it shrinks back past the point of its original position (I do NOT understand that!), but it makes the metal thicker in that area. When you hit that area with a hammer it stretches / thins the metal back to its original thickness.

To make this more clear try this: Take a piece of sheetmetal 12" x 12" and shear it in half resulting in two pieces 6" x 12". Lay them side by side, clamp them both down, then weld a small tack at one end of the 'joint' seam. Let it cool, then unclamp and the two pieces of metal will be be laying next to each other and be parrallel over the length of the panels. Now, place another tack at a position about one inch from the original tack. What you will see as the heat dissipates, is that the far end of the panels, they will spread apart. Do nothing, but let them cool down and before long the far ends of the panels will shink back as they cool to the point that they will overlap! Then using a hammer and dolly, hit the second tack until the far ends are again parrallel. This will maintain the metals thickness and alignment, but I agree with you that it may slightly 'harden' the metal at the tack area. But this exposes what I think is the trick/advantage of correct hammer welding. With experience you learn to do the 'hammer' part while the metal is still warm/hot, giving it time to anneal as it cools.

I have recently designed and built a moderate sized power hammer and a custom English wheel and in discussing wheels and dies with experienced suppliers, they all cautioned me about running metal panels thru their dies and/or wheels that have been MIG welded. They have told me, that even with hardened tooling it 'marks' their wheels and dies, and are so convinced of that, they warm you before purchasing. I ruined one of the lower anvil wheels on my new English wheel, so I believe them as well! I have formed the opinion that for whatever reason, MIG in particular results in a much harder, faster cooled weld and that that results in a brittle area just adjacent to the weld. That is where all the breakage occured in the race car environment.

Again, it's just my OPINION, that if you are just welding to join something together, MIG is one option, TIG is perhaps a better option for sheet metal, but if you are going to do any panel 'shaping' subsequent to welding, gas (hammer)/welding is much prefered, as it maintains both the metals thickness and approximate ductility and malleability. All of this is also influenced by filler material and resulting 'puddle' chemistry.

Your thoughts?

Anybodies thoughts? I'm still learning this 'stuff'.

[AlfinCT]

Curt Campbell: I'd like to know more about the mutli-function welder you mentioned. Where can I (we) learn more about it?

[Terry, NJ]

Bob. I know those welds! LOL! However, I first learned to weld with a big (Huge by these standards) MIG that spit out 5/32 flux cored wire to make a 3/4 wide bead on a 100 inch dia section of core for a concrete pipe, on a turntable. Lotsa puddle there! Later, I used to weld stands for a turntable. These stands were 2X4 steel tubing. Looks were important so I dressed them up a litttle by weaving my arc in a circular pattern and creating the proverbial "row of dimes". Lot of puddling there too. Shows like O.C.C. have to set up everything by time, appearance, story line, ETC. They bear little resemblance to reality. However, I worked in a shop where most of the tacks were done the O.C.C. way. IF you are tacking this way, Wear glasses. The short wave UV is not capable of penetrating glass. But your eyes will still get the full effect of the brightness.
Terry

Originally Posted by Roadster62

The MIG welds I've seen were "Orange County Chopper" style MIG welds. Close your eyes and zap type welds. The MIG unit I've had a chance to use just spits out wire there is NO CONTROL what so ever. Gas and TIG you get to add rod to a puddle. MIG is a totally different concept. I felt good about all the stick welds I put down on heavy gauge steel, strick has a puddle too. I'm sure there are MIG welders that do fine work, stuff I've seen was ugly, and there was nothing that attracted me to learning MIG. Bob

[d.j. moordigian]

Originally Posted by fordgarage

I have also used silicon bronze MIG wire like we used at work. Different animal.

Vince,

It's nice to heli-arc with, but not too do body work with! You can paint
over it, but it will bubble up under the paint, like Braze.

[PetesPonies]

I am referencing "Easy Grind" MIG wire. It's an ESAB product. Thew beads are workable.

Also, here's a decent thread for people interested in welding info and pictures.

http://www.garagejournal.com/forum/s...G+PATCH+PANELS

[Brobrian]

This thread cost me $600!
I bought a mig, some wire, gas bottle and regulator. Haven't welded since 1976, but now I have plans for 4 welding projects. I'll start simple (welder cart) and work my way up to a lumber rack for my '31 pickup.
Maybe I'd better weld up a doghouse for myself first.
"Tools + practice = talent" is what I'm hoping.

[PetesPonies]

Money well spent . . enjoy!

[CarlG]

Originally Posted by Brobrian

This thread cost me $600!
I bought ....

Isn't that what this hobby is all about??? An excuse to get more tools!

[d.j. moordigian]

Well,...hopefully Steve's question was answered?

Will,
Are you going to use Oxy/Acetylene, or Oxy/Hydrogen? Tutorial?

Thanks, Dudley

[CarlG]

Does "Steve Plucker" ever answer questions asked by "329s"? Or possibly the other way around??

[d.j. moordigian]

That's GOOD Carl ! The heat is finely getting to you up there....

[RockHillWill]

Dudley, I think I will start with the Oxygen/Acetylene as I have the stuff to do that with. The friend that I refered to in an earlier post used the Oxygen/Hydrogen to build all the sprint cars years ago, and has just recently acquired that equipment again, and is willing to teach me if I am interested. I also discovered when I got out my aluminum welding stuff, including a HENROB unit, that I own a nice new Cobalt Blue shield #6 that I got from Jim Spradley. Were there some safety issues with using that lens?

He and I have discussed the possibility of building a LSR car for Bonnevillle, as it appears that the record for one of the 'stock' model A engine classes is quite low at the present time, and he has some enthusiasm, as well as some past experience there.

That's all I need. ANOTHER 'project'!