Welder and gas settings ?'s

Last night I was welding up some cuts on one of the doors of my Chevroloy project. I kept occasionally burning through the metal. I have some questions about the settings I was using on my welder.

I'm using a Lincoln Weldpak 100 with MIG gas conversion.
Because the metal is fairly thin (18 gauge?) I was using it on the "A" setting ('A' is for the thinnest metal, 'D' is for the thickest.) I had my gas pressure set at around 16-17 pounds. I had my wire speed set at about 2-3.
I thought (and I may be wrong) that turning up the pressure on the gas (went to about 19psi) would help prevent burn-through because it would make alittle 'colder' weld. Is that right? I'm not sure if seemed to help or not.
A few minutes later I turned my wire speed up to 4-5 and I tried to move a little faster. That seems to have also helped some.

I know because the metal is so thin that I shouldn't weld more than around one inch at a time. I tried to stagger the welds out to prevent that.

Any suggestions?

Jay

The gas is for shielding the forming weld from outside air. The pressure settings are only what it takes to shield the weld with the shielding gas. I turn mine up when welding outside. The pressure change should mostly effect how much gas you are using, or wasting. Not much else.

Does what you are welding fit real good?
Can you clamp a piece of copper behind the joint?

Flow gauges are calibrated in Cubic Feet per minute.
Increasing flow won't influence temperature or burn through.
Check the manual for settings.

Try backing up the weld with a piece of Copper plate,when tacking.
That reduces the chances of burn through.

Most people pulse the trigger,on and off.
1 second on for tacking,3 seconds for a short bead.

Some models will accept a bolt on timer.

Good t know...

I was using a piece of aluminum (because I happened to have it in the shop) behind the metal as I was welding it.

I'll turn my gas pressure back down to 16-17 CFM and try 'pulsing' the trigger.

Thanks, Jay

Turn your wire speed up, just a little faster than the recommended speed. The idea is, you are using more filler material, with less amperage, and it seems to run "cooler", the danger being little or no penetration. And nasty metal boggers hanging off your welds (shiver). Pulse welding will help more than anything. The thinner the metal, the less pulse, time wise.

I bragged once on the pipline, that I could weld two tin cans together, (Stick), my helper brought two cans the next day, and I had to put my money where my mouth was. With mig, the best trick I ever pulled off was welding steel brake line together, for a low pressure application, (Oil tube).
Welding is mostly practice, and being familiar with your machine. Shoot, If I can do it, a drunk monkey could pull it off.

Wire size

Alien,
Didn't see where u said what wire size u're usin'! I had that problem on my truck (i as usin' .35) & the Bonehead recommended I use .22. That made a big difference for me on thin tin!

BoB

The advantage of dropping a wire size to .025/.023 is you can crank the amps down and weld a smaller spot. If you need to fill gaps you are still able to speed up the wire and match the larger wire size. Too often if you are running .035, it takes more amps just to make the wire flow, then before you know it you are running too hot. I think it helps on thin materials. You will have to change the wire, and the tips.

I have .023 in a small 120v lincoln I have. Its amazing what can be welded with this small wire. The pressure you set on the rollers to feed the wire is important too.

I also agree pulsing works great for small stuff when you are getting burn thru.

welding

back when i used to smash cars for fun ( demolition derbys ) we would use flux core 45 wire with argon on 15# for plating door seams and body seams. found out it makes a harder weld. would prob be easy to shape and grind due to a more consistant mix.

Bonehead said:

Welding is mostly practice, and being familiar with your machine. Shoot, If I can do it, a drunk monkey could pull it off.

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I cant stress this enough. When ever sombody wants to learn on my machines, I try to stress this fact. Also being able to 'diagnose' your weld is a huge help, are you too hot? to much filler? etc etc. Only practice can tell ya.

I would buy a small cheep spool of lighter wire and some tips (shouldnt be more that $20) and they try it. I am usualy to lazy to swap my wire around and end up pulling my hair out welding sheet metal with my Miller 200 and 035

I have also used this little trick, get some wire or oxy-acetalene mild rod and feed it in to the puddle. This extra filler can act as a heat sink plus put more filler in. I find this gives me more control that than the faster wire speed would to lay down the same amount of filler.

What shielding gas you use makes a differnce also...

Argon makes for a cooler weld... many places suggest a mix for all around, the mix usually contains helium, the helium will burn hotter... C02 is somewhere in between...

I use Argon / CO2 mix gas to make the welds really clean.

Best kept secret in rod building

This company manufactures a mig wire called "EASY GRIND" ...it is a 30,000 psi wire, most mig wire is 70s6 wire that is 70,000 psi, so this wire welds at lower heat settings and because of its lower tensil strength it is easier to grind reducing the warping factor. It's easier to fill gaps in thin sheet with it. Everyone should give it try, I think you'll be surprised how much easier it is to work with welding boby panels....have a nice day
http://www.esabna.com/

if this is just for body work. then pulse welding should be fine. id never recommend pulse welding something structural.

DC*90 said:

if this is just for body work. then pulse welding should be fine. id never recommend pulse welding something structural.

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Same from me, I have had this discussion many times. I had a wyo tec graduate, tell me that he was taught to pulse weld structral stuff there.
He did not agree with it at the time, and I don't agree with it now. Too much emphisis is put on how pretty the weld is, and not how good it is.
Pulse welding has it's place, sheet metal, filler, etc. Not structural.