Can a MIG work for sheet metal?

[Daren]

Can a MIG welder work for patch paneling ect or is a TIG best? Would a MIG welder capable of dealing with sheet metal cost more than a TIG?

I want to do patch paneling. Is a MIG inappropriate for the job?

[formula350]

A mig will work, I just bought one for it

[oestek]

Daren, a MIG will work all day long for sheet metal. Just be sure to practice dialing-in your welder for your metal thickness and proper wire speed, and keep everything cool. Here's a quick video showing the easiest, most effective way to set up a welder that we've come across. Hope it helps!

[SShep71]

IMO a mig is better for patches than a TIG in most cases. The TIG build up a LOT of heat and causes a lot of distortion. It just depends on your situation, a good MIG with ER70s .023 wire will do the job every time. Look at using different shielding gas too. If you have an excess of $$ look into a MIG with pulsing capabilities. Just make sure you get lots of practice time in. GL!

[68RS350]

The nice thing about tig welding sheetmetal is, it's easy to remove the weld and grind it smooth and you can still shrink and stretch the the area you welded.

[Daren]

IMO a mig is better for patches than a TIG in most cases. The TIG build up a LOT of heat and causes a lot of distortion. It just depends on your situation, a good MIG with ER70s .023 wire will do the job every time. Look at using different shielding gas too. If you have an excess of $$ look into a MIG with pulsing capabilities. Just make sure you get lots of practice time in. GL!

Glad I asked the question. My take on this initially was that a TIG welder had a cooler flame and is best for sheet metal. I also was under the impression that a MIG welder capable of dealing with sheet metal needed to have the ability to produce a cooler flame and that such units were expensive.

Looks like I was wrong on all accounts. A cheapie Home Depot MIG should do the trick then? I'm only interested in a welder that can weld sheet metal at the lowest price point, even if that means I buy used. MIG it is then?

[SShep71]

Without getting far into the theory of welding and making this a science class. You are partially correct, the TIG arc can run cooler than the MIG but it can run hotter than the MIG and vise-versa. Its all about adjustability. The downfall of a TIG is that its almost constant heat input to the pannel. The heat buildup during the weld distorts the pannel. The up side to the TIG weld is that like mentioned above it is a softer weld that is very workable in the post weld phase (depending on the filler rod). So you can grind it, shrink it, streach it, and all that jazz. The MIG weld is going to be a harder weld that is more prone to cracking when post weld work is done. The MIG done properly is a series of spot welds that develop a solid bead. That leads to the least amount of heat input and results in less time spent straightening the pannel afterwards, but more time grinding and cleanup. Thats why some people prefer MIG and some people prefer TIG. If you can look for a smaller Lincoln Electric or Miller welder. Just not flux core. Buy a welder, and buy some .023 ER70S2 wire, and a blottle of 92/8 mix gas. Get some 18-22 gauge sheetmetal and do several types of joints and experiment with the heat, wire speed, and gas flow settings. The more adjustable the welder the more expensive it is going to be, but its usually worth it in the long run. Try craigslist! I hope this helped

[Roberts68]

Nice video Kevin. Well spoken and concise without being corny or talking down to the viewer.
You give me a case of job envy for all the cool projects and toys... er, I mean TOOLS which you get to play with.

[Fras]

Do you have to use gas when welding with a mig?

[Andrew McBride]

I think most people would agree that welding with gas is far better than flux. I have both and prefer welding with gas when doing sheetmetal work.

[Roberts68]

The gas serves to sheild the arc and you will get a much cleaner weld, better in all aspects. There is also flux core wire which many 110 machines can use, think lowest priced machines utilize flux core wire and then you step up to gas regulator machines. There is product overlap in most brands where the machines are dual purpose flux/gas but to alternate you must change the wire spool and machine polarity.
Some flux core machines can be upgraded to gas but since it requires a different gun/liner for the gas to pass through it is not real cost effective to buy cheap and upgrade... and still have a compromise.
I have not used flux core, but have not heard anything about it that would make me want to except for portability in a maintenance or farm application... not anything I'd want to use on a near and dear musclecar.

[formula350]

Look up flux core vs. Mig on YouTube and you can see and hear the difference. Plus the gas keeps it cool and causes less warping

[exwestracer]

If you are trying to control distortion when MIG welding sheet metal, one of the best ways to do it is by stitch welding. Neither MIG or TIG is a "cooler" weld...they both have to melt the base metal, right? The MIG weld is typically harder to hammer and dolly out because the large amount of filler material causes 2 problems. There is more buildup to deal with, and the puddle is quenched quicker, leading to a harder material in the weld zone.

Forget flux core welding on sheet metal...really. I'm sure some people will shout that they've done it; fine. It's still not the right process.

[CRead01]

man... great video on setup.

I have both a mig and a tig but after seeing how simple setting it up that way I feel kinda a little stupid for doing it by welding on a test pannel then adjusting then welding and adjusting and so on.

[jlcustomz]

I'll agree with the line of thought that for most people in most sheetmetal repair, the mig is 1st choice over tig. I also use .023 for sheet & for finer work when spotting , you could snip the rounded end off for a hotter cleaner start each time. Also go a little at a time on grinding to prevent warp. You could lightly hit the highest of the welds with a cutoff wheel or metal grinding disc before switching to a sanding disc.

As far as the mig vs tig heat arguement, many of the best shops use mig for tacking , then tig. Also the better tig users are pretty wild with the footpedal action, as in hitting it heavy to heat up fast & then backing off--get in & get out.

[Daren]

Thanks for the input everyone. I am now very well informed. I'm looking at picking up a good MIG and plasma combo. I've just picked up an IH scout 80 to begin metal work on as a learning experience, plus I need a plow vehicle and I love the things. I see mini tubing and a 69 bird in my future as well. As I gain experience I may pick up a TIG just for the fun of it.

Thank you everyone.

[SShep71]

No worries man, thats why we are here. Free information is the best way to get people on track. If you lived in so cal and I wasnt deployed I would have you come to my garage and teach you some tricks just as I have done several times before.

[Daren]

Even flux core should really be used with a shielding gas, right? Just because you can weld without doesn't mean you should or that is how it is meant to be used.

My limited understanding is that flux core is used to obtain a deeper weld hence the use of flux core and a shielding gas when fabricating battleships and such, but I know very little.

Why is flux core with shielding gas not recommend for sheet metal work? Too deep a weld or something, or are people using flux core without a shielding gas and this is bad?

No worries man, thats why we are here. Free information is the best way to get people on track. If you lived in so cal and I wasnt deployed I would have you come to my garage and teach you some tricks just as I have done several times before.

Sounds like fun. Have fun on that deployment. I managed to enjoy my two to Iraq through the highs and lows while making the most of things. Just a big blur now a days.

[SShep71]

Yeah man I got lucky and wound up with some internet access so it helps to pass the time after patrols and such. Getting a little deeper into this, there are two different types of flux core, standard flux core which is meant to be used by itself, and dual-shield which is a flux core wire that is used in conjunction with actual shiedling gas. You are right that flux core is used to build battleships and large vessels, but that is due to the fact that the actual area (yard) the work is being done in is not very friendly to a gas shield. The wind and turbulance cause major problems that will lead to porosity when welding. A lot of production welding ship yards, construction sites, etc. use flux because it cuts down on expenses of gas and set up times. It also makes the job easier because you wont have as many problems with weld porosity. The weld at times can produce a "deeper" weld when viewed from a cross section, but a good weld is deep and wide. The reason flux core is not good for sheet metal is because of the heat and burn through, also when just spotting with flux the wled can have porosity problems. It is caused by an undeveloped gas pocket, unlike gas welding which provides a gas pocket prior to the start of the arc.

[exwestracer]

And that's it in a nutshell... The idea behind flux core is that it works in any environment, and you don't have to tote a bottle around with the welder. Again, don't bother with "dual-shield". If you're gonna run gas, just use solid wire.