Thread: MIG vs TIG Let's get ready to Rumble!

Tweet

I am getting ready to put my 1932 frame together and want some opinions on the subject. I have had guys that TIG weld tell me that it looks nice and all, but there is a very high heat transfer which can affect metal hardness. On the other hand MIG does a good job, but some say it isn't strong enough.
Now I know back in the 50's when guys were building rods they only used ARC welders. Is it really just a matter of preference?

I think it is a preference. My 33 has 550hp (dyno'd) and I built my frame using a MIG. No problems at all. If you are a good welder than you wouldnt have a problem using any type of welding.

I've used all three processes.

I use TIG for most things now, but I wouldn't hestitate to use the others in certain situations.

TIG is going to require good fits and clean metal. I think it looks good, but that's just my opinion. I like the control it gives you. You can do things that are next to impossible with any other method.

If you can't get the metal perfectly clean, then stick will likely give better results. It's also good in tight and/or deep places with limited room. I have a couple places on my T that will get E7018 stick welds for this reason.

Mig is probably the easiest to use, but it's also pretty easy to screw up. You can get welds that look good, but have no real penetration.

Bottom line is, use what you are 100% confident with. The important thing is consistent strong welds. You can get that with all three if you practice enough.

By the way, you would be surprised at how many airplanes and race car frames were gas welded and brazed together in the old days. Not that I'm recommending those processes, but I have used them.

I'm pretty good with a stick, better with a MIG, but I have never done TIG. I am probably going to go with MIG. All steel is new or bead blasted so it should not be a problem.

Originally Posted by Uptown83

I think it is a preference. My 33 has 550hp (dyno'd) and I built my frame using a MIG. No problems at all. If you are a good welder than you wouldnt have a problem using any type of welding.

I agree. Also, TIG is alot more time consuming than MIG or stick.

Be careful with blasting. You can drive dirt or other impurities into the surface and cause porosity in your welds.

MIG is more tolerant of dirty metal than TIG, but not much.

I use a pneumatic sander to clean the surface for either one before welding.

I have to agree with Hotrod46, if your good with mig then do it that way. I prefere tig only because its cleaner and i can manipulate it better , but mig is also nice to.

All have their place. I've used both on frames, as mentioned tig requires a lot more careful fitment of all the pieces but IMO leaves a great looking weld. Mig is much faster and done correctly plenty strong for a hot rod. As a standard rule around here, if it's going to go over 140 mph use a tig..... I've crashed (hard) with cages welded up with both mig and tig, none of them came in on me.....

I don't think this one will ever see 140 mph! I'm building it for cruisin not racing. Plus I'm using a flathead which for now is mostly stock, I probably am looking at 150 Horsepower max.

I use TIG because I have a nice new one, it's clean and doesn't leave spatter all over, Looks nice, easy to get good solid welds, I can weld almost any common material, no cleanup.....

You need a good fit, but no big deal. If you are "gap welding" with MIG you are kidding yourself on strength. It may get by because of shear volume of weld but if really tested it will not pass. You may be able to weld aluminum with practice with MIG but it will take time to get a good weld. Look at aluminum trailers. These guys do it all day every day so the welds are usually pretty good. MIG does a good job on mild steel but you need good fit and good wire for 4130 just as Tig plus you really have to work on penetration.

jmho

I think speed is also a factor, is it not? Mig is better when you are doing long passes and lots of them, but tig is a lot slower process, as I understand it.

I'm a little surprised the tig I got Dan hasn't been used more, but he is so comforable with his mig that he uses it almost exclusively. My buddy who owns the body shop bought the very same tig at the same time period, and he hasn't used his yet. He says he's waiting for Dan to teach him how.

Maybe when he starts on his body the tig will be used then.

Don

I've heard the same thing about TIG, that it is slow. Maybe I'll weld the center and rear crossmembers MIG, then take the frame to a buddy's to TIG the front crossmember, motor mounts, and shock mounts.

There isn't any doubt that TIG is slower more complicated and costly than MIG. It is also more difficult to master however you should be able to do pretty well if you can gas weld easily. You need to use both hands and one foot or the other, maybe an elbow for the pedal, maybe have someone else stand on the pedal( much harder) maybe just roll over on it. I always seem to be out of position with the tig but it isn't that hard. Plus I growl at anybody when they walk on my cables. You need a good helmet and an auto dark is nice for most applications. I still use my dedicated darks however. Just old fashioned but I hate getting buzzed when you block the light sensor.

if you are playing bet your life then it is tig for me . not hard to use and they have thumd wheel on the torch body no need for the foot pedal use to do all my work with mig .now all my work i use my tig

I went to the thumb control, too. Still put the foot pedal on for bench welding, but I use the thumb control for out of position welding....