CJ3b....That is what the vin tag says.

[inVERt'D]

Ok, good--that's what I was hoping to hear. Your wire feed rate and amperage have to compliment each other. Generally, higher wire speed is needed for higher amperage and vice versa. Wire thickness also plays a part: smaller diameter wire requires a higher feed rate for a given amperage. Thicker wire is harder to melt and can stab the metal instead of melt to it. Conversely, thin wire can melt too easily at higher amperages, melting itself off in your tip.

For the 18GA stuff you'll be doing, you'll want an .023 wire. Make sure you get tips to match. You don't want to use .035 tips with .023 wire if you can help it.

You'll have to play with it, but it will mean less grinding and grief if you can get a fairly flat bead--which means more heat. Welding downhill is a popular body man technique, because it tends to result in less penetration and a prettier bead than, say, uphill. A technique I like on the MIG is to use a moderate amount of heat (on my 220V machine) and weld-pause-weld-pause rhythm. Basically you make a little button or "dime," pause, then make another. Each button can be made with a horizontal, V, or circular stroke. You can get complete fusion in each segment of the weld because you're fairly hot. On the other hand, you can control distortion and blow-through by watching how the metal responds button-button-by-button. I also use that technique for welding thick and thin stuff together; a little technique, and you can get full penetration in both without blowing through the thin stuff...much.

[jonah]

Cool, thanks for the info. The wire in there now is .030. I will pick up some of the .023 and some tips when I go to get some gas. I will have to practice on sheet metal as this will be my first attempt at bodywork, I will definitely try your techniques!

I can't wait to get going...

[inVERt'D]

My pleasure. One thing you may know about MIG, it's very touchy when it comes to wind. You can turn your flow rate up to 12 or so if you're outside with light air movement, but any breeze more than a few mph will make things much more challenging. You may have to improvise some kind of shelter or windscreen. Often I have to just cup my hand around my weld puddle and wait out the gusts. Flux core wire, as you may know, lends itself much better to windy conditions.

[jonah]

Yeah, I have read that about mig. I am working outside, but I can drop down the sides of my EZup if I need to. I am borrowing a little lincoln weldpak 100, .035 flux core only. I did a test on the sheet metal, but I couldn't get very good results with it. I am hoping I can do better with the mig.

Thanks again.

[bails85]

i just had this problem with my xj (cancer repair). trust me do not use flux on the sheet metal. on a 110 machine i like to run 030. 023 might be a little small. on my machine for sheet metal i turn the heat to the lowest setting and run the wire speed at 2 1/2. it goes from 1-10. sheet metal is not fun to deal with. the xj sheet metal is vey thin and even on low i had to use some 1/8 inch plate in certain places to keep it from blowing through. one thing that could be screwing with u is the contacts in side the machine. sometimes when people try to turn a 110 machine all the way up and burn big material it will put strain on the contacts inside the machine itself. pull the cover off and just take a peek at the inside. maybe even wire brush them if needed. and the tip just take some sand paper to it and a small machinist drill bit to it just to clear it up because there can be some slagg on it from previous welding. if u can arc weld then u can mig weld. just spend a 1/2 hour or so screwing with it to get it setup properly. u will know when u got it. good luck.

[inVERt'D]

I disagree. .023 is the better choice for two reasons: 110V machine and sheet metal. It can be used to weld the joint smoothly with less heat and therefore less blow-thru and and a smaller bead (less grinding).

I just used flux core on sheet metal the other day. I welded a 1" x 5" long hole completely closed using only weld bead. Flux core doesn't tend to be as pretty as MIG--unless the MIG weld is getting fried from having the shielding gas blown off.

You're right, if he can SMAW, he can GMAW or FCAW.

[bails85]

u may be right in that aspect i have only used 030 on sheet metal. but i do know that when i went from 035 to 030 the weld was hotter because the machine takes less effort to heatr up smaller wire. just my though on it. but im not perfect so try 023 it might be worth the 20 dollars.

[jonah]

Alright, so I got down to the gas store and got a full bottle. But I decided to hold off on anything else until I found out if the machine was even going to work. So I hooked it up, had one small leak but go it fixed and fired it up.

Here are the first test beads on 18 ga. with the .030 wire. Worked pretty good, I think I might pick up some .023 and give it a go. Although I was concerned about the wire feed, there is only one size groove. Is that the norm? I thought I remembered reading that you had to change the drive wheel on some migs for different size wire.



Here is my hack job repair of the wire feed clamp and trigger.



I only have a flow regulator on the gas line, should I have a pressure regulator as well? It really sounds like the gas is coming out fast. I had the flow set to 9 cfh. Anyway, I can already see why everyone uses mig, nice and clean.

[bails85]

the grove in the drive wheels should be o.s.f.a. there is usually an adjuster screw to put a little more tension on it though. it looks like yours is missing. and your regulator shouls have two guages on it so u can properly adjust your flow and pressure. u dont want to waste your gas. that shit aint cheap. try taking the machine to airgas. they might have a piece there that will fit the drive tensioner. and a gun. if it works out u might just have a decent machine for little money. oh and what gas are u using u shouldnt have so much black around your bead. either that or youre holding the nozzle to far from your material. dont worry ull get it.

[inVERt'D]

Good point about the drive wheel. I have a couple of grooves in mine and half the time I don't bother to flip it. Having the tensioner set right and the gun cable as straight as reasonably possible seem to be much more important on my particular machine, at least. If you think .023 might be too small, you could try .025 or just use the .030. A lot of those 110V machines are setup for smaller gauge wire, though--.030 should be on the larger end of the spectrum for that thing.

Got a pic of your regulator and gauges you could throw up? You should have a tank pressure gauge, a flow gauge and adjuster on your regulator. If it's an Argon/ CO2 regulator you should be good to go.

Here's a cool website by a guy who is actually an pro welder (unlike me). This is a link to his 20 Best MIG Tips.

http://www.weldingtipsandtricks.com/...-articles.html

[bails85]

try to stich weld it too. (circular tack welds) comes out really nice that way. cant do it with flux but is bitching with a mig.

[jonah]

No pics of the regulator right now, but it only has a one gauge for flow, no tank pressure gauge. I will have to look into a pressure regulator. As for the black around the welds, I had the nozzle really close, but it was a little breezy. Also I read that the gas should be about 15 cfh and I was at 9, maybe I didn't have enough gas coming out. I need to check out a properly set up system so I have a better idea of what is right. Oh yeah, I am using Argon/ CO2 (75%/25% I think).

The tensioner is broken, but my homemade one, although ugly, is fully adjustable. I found the correct replacement part online, but it was $40 and I didn't want to spend the money on this machine. But if it seems to be working, maybe I will.

Anyway, even as imperfect as my first tests were, they were way better than the flux core was doing. If I can get it dialed in a bit more I will be happy.

Thanks for the help.

[Gary]

Here's a cool website by a guy who is actually an pro welder (unlike me). This is a link to his 20 Best MIG Tips.

http://www.weldingtipsandtricks.com/...-articles.html

Thanks for the link. Great info on this website, already learned a few things.

Nice job on your build :thumbs_up, watching you makes me want to build something myself.

[jonah]

Thanks Gary, I am ready to be done building and start driving! But I have a ways to go still...

That link is a great resource. I have been reading like mad.

[inVERt'D]

Yeah, I like that website a lot--been very useful for me too.

I wouldn't worry about that carbon. In fact, I'd bet that carbon is from the shielding gas itself. The steel you're welding doesn't have that much carbon in it. The best (and worst) indication of not enough shielding gas is porousity in your weld bead. Try welding a little with the gas off or in a good breeze so that you can get an ear for that distinctive crackling sound. It's the sound of your bead being oxidized into worthlessness.

From those pics above, we know that thing can weld, and that it can get hot enough for your 18 GA. The thing with that thin metal is you really don't want to distort it. The HAF (heat affected zone) could very easily warped. It looks like you might be going a little hot for a continuous bead. When you actually do your body panels, use a lot of tack welds to hold things in line. Also, stitch welds as bails85 referenced above are useful. For instance, weld and inch, skip an inch, weld another inch; then after it's cooled, go back and fill those in.