The Stovebolt Site Forums The Shop Area Paint and Body Shop Welder setup

Guys,

Wanted to see what setting ya'll were using to weld sheet metal with? I have a Millermatic 212 running 75/25 gas and .035" wire. Welds have not been laying down nice and flat. I'm in an area that I know it is hard to get good ground (kickpanel, cowl) but the surfaces being welded are nice and clean. Anyone shoot me with a baseline to start from? There is no recommendation from the machine for 19ga and splitting the difference b/w 18 and 20ga hasn't produced results. Thanks!

You have way too big of wire
. Use the .021 or there abouts

would .030" be too big?

I would go to .020 wire for best results.

Not much difference between .035 and .030. It'd be hard to tell the difference without a micrometer,

[on edit] available wire diameters are 0.023, 0.030, and 0.035. I'd use the smallest available (0.023). If we'd been using mortars, we'd almost be ready for "fire for effect", as we were all over the place with sizes.

.025 wire, set pretty hot. You must have a good ground. Clean a ground area for ground clamp or magnetic ground puck. Need to practice on the pieces you cut out. I've never had "nice and flat" spot welds on thin sheet metal. Your manual will tell you about tall welds vs flat. Several factors other than wire size and settings. Sounds like "cold" welds. Experiment with trigger speed, stickout, angle, small quick loop, where you start weld, etc.
First set voltage to one gauge higher than chart, then adjust wire speed to get the sound and the weld. Tweak from there. I believe the charts are designed for continuous welds where the metal gets hotter and hotter and you keep moving. With the spot-dot weld method on thin sheet, we need some quick high power/high wire speed bursts using .025. The charts do not contemplate spot-dot welds. Together with other factors like home voltage supply, these charts are just a lab guess.

When I get stumped I practice on a test piece. I find that adjusting to burn thru and backing off is easier to find the sweet spot than starting low and trying to work up to a good weld. You kind of never know for sure if you can't see the back side penetration using the "work your way up" method. Burn thru is your max penetration Backing off will place you in the high end. Lotsa ways to skin a cat.

Don't try to run a continuous bead. Skip-weld in several areas, never more than 1/4" at a time, and move several inches away for the next stitch. That keeps from distorting the panel due to big temperature changes. It also helps if you have several patch panels test-fitted and tacked into place so you can switch to another place and make a few welds while things cool down at the first weld site. Then go back with an angle grinder and smooth up the weld beads after some cooling happens. Definitely run the smallest wire you can find, hot and high speed.
Jerry

I like 023 'easy grind' for sheet metal work and patch panels. There is plenty of it buried in my 59.

Excellent. I know the spot and dot so not to warp it. I had not considered that they were likely estimating the settings for constant bead and not for momentary blasts. Do I need to replace the liner on the gun or just put new wire in? I don't have that much to weld.

You just need to replace the tip with the correct diameter to match the wire size.