ShopTalk Forums | Aircooled VW Tech & Restoration Help

I've been practicing my welding with my new miller 140, and I've been doing pretty good...that is until I tried welding the thinner bug-type metals. I find that I can weld 1/4, 1/8, and a bit thinner than that quite well, but as soon as I start trying to do ANY sort of welding on 20-22-24 gauge, I'm getting my you know what handed to me.

One of two things happen. Either it blows out, or I get really dirty, beaded welds, and it when I weld it sounds like a first generation gattling gun POP--POPOPOPOPOPOP-POP, and I've already spent the better part of 2 hours mucking about with the voltage and speed settings. A number of you have recommended the miller 140, and I know the thin beetle-type sheet metal can be welded with success with this MIG, so obviously the problem has to do with either my selection of practice metal, or my technique, or both.


The 22? gauge sheet metal I bought from the store looks a lot like its been coated with something. The only comparison I can think to make is that it looks a lot like the sheet metal used for cold air return ducts on a modern house. I find that when I weld, I get a skin of whispy white ash surrounding the weld.


What should I be looking for in a practice metal, both sheet and plate? When I went to the store there was about 10 kinds of steel, and I had no idea what to buy. What should I be using to cut my sheet metal to shape? Right now I'm using tin snips for the really thin stuff, and a dremel for the thick stuff, and I get the feeling neither are the correct tools.


Thanks again guys.

With thin gauge metal, you need to "stitch" it. Trying to lay a bead will just blow through. Look at the way Kelly welds old Busses: http://www.metwiz.com/

Raymondo wrote:
One of two things happen. Either it blows out, or I get really dirty, beaded welds, and it when I weld it sounds like a first generation gattling gun POP--POPOPOPOPOPOP-POP, and I've already spent the better part of 2 hours mucking about with the voltage and speed settings.


so obviously the problem has to do with either my selection of practice metal, or my technique, or both.


The 22? gauge sheet metal I bought from the store looks a lot like its been coated with something. The only comparison I can think to make is that it looks a lot like the sheet metal used for cold air return ducts on a modern house. I find that when I weld, I get a skin of whispy white ash surrounding the weld.

Thanks again guys.

I am also trying to learn how to weld, but I think I know what your problem is...It's the metal that you are using to practice with...

You got some galvanized metal to practice with, and what is happening when you weld it is that you are burning the zinc coating off, and that is why it is popping and making bad welds. I went through the same thing making some stands to put my buggy frame on out of some old drain pipe we had laying around the house. I just brushed the dirt and rust off of the ends that I was welding up, and it did that same thing with the popping and bad welds. On some of the pieces I went back and ground the coating off, and it welded fine then. If you keep using the metal you bought, grind or sand the coating off and see that it does. Also, try not to inhale the fumes from it, because they can make some people sick...its called metal fume fever. I think basically it is like and allergic reaction to the zinc fumes that some people get.

Instead of buying metal to practice welding, why don't you go to the junk yard and buy a bunch of old car hoods, doors, etc to practice on? That way you will be saving a lot of money, and you will be using the right kind of metal. Even better would be to get some unusable vw metal sheet metal from someone, since then you would know that you had the right gauge metal that your vw's will have...

Galvanized material off gasses when you weld it and it is not good to inhale the fumes!

You can also us a strip of copper or AL to back the weld. The copper or AL act as a heat sink and may let you do other than tiny stitch welds.

What size wire are you using .023 is a lot better to weld thin sheet metal with than .035. I have an .035 liner in my welder and just change the wire and tips for thick and thin welding materials.

I am using 23 size wire with 75/25 gas mix. Thanks for the heads up on the fumes guys, good thing I had the garage door open, but still.


I'll ask around at the local VW club and see if I cant get my hands on a busted decklid and some thinner metal to practice on. Any tips you guys have for stitch welding?


Thanks again.

Raymondo wrote:I am using 23 size wire with 75/25 gas mix. Thanks for the heads up on the fumes guys, good thing I had the garage door open, but still.


I'll ask around at the local VW club and see if I cant get my hands on a busted decklid and some thinner metal to practice on. Any tips you guys have for stitch welding?


Thanks again.

You got to practice a lot to weld thin stuff make sure it is clean as a whistle.

Also, make sure your gas flow meter is set at around "20" on the gauge, not sure of the measurement? I was using too much gas and had trouble keeping an arc. Make sure both surfaces are as clean as you can get them and you have a good clean ground. I went to a local high school that had a evening welding class for a few months and learned alot. I yse a Miller 175 and find I set my amp dial at about 2-2.5 and the wire speed around 35-40 with .23 wire. Like the other guy said, get some old vw metal and keep practicing, you'll get it