View Full Version : sheet metal starting point
04-25-2006, 10:27 PM
I am about to start welding 14ga galv. sheet metal for some auto body repairs.
I will be using a Lincoln Pro-Mig 175.
Can anyone recommend wire size, votalge, and spool speed as a baseline statrting point?
Thanks in advance.
04-27-2006, 11:23 AM
mt, first off, i'm not an expert so take what i have to say with a grain of........ I asked a similar question with requards to welding galv. steel and the response i got was somewhat alarming. evidently galvanized steel is coated with a chemical or bond that when heated(like welding) gives off quite a poisonous plume. there was some other discussion about it and some "tricks of the trade" of how to elliminate the danger. If i can find the post, i'll link it for you or you can check in the general questions part of the forum. as far as wire size and volts setting and wire speed, start with the suggested settings on the inside panel of your machine. it gives you a very close starting point and you can fine tune from there. I'm sure some of the forum regulars and other experts will chime in here and give you better info, just be careful about the galvanized stuff.
I've also got to say that, being an engineer in the auto buiz on the body shop side of things, i've never seen galv. steel used for body panels or any other parts of the auto for that matter. if your concerned with rust, just use a good primer and paint to cover and it'll be just fine.
04-27-2006, 11:37 AM
I sometimes find the machines recommended settings are a little too hot for my taste. But they are close and will get you started. For galvenized, you want a lot of ventilation. I usually have a small fan next to my welding work area to blow fumes away especiallyi for galvenized stuff.
04-27-2006, 04:35 PM
That fan will have to be placed very carefully, so as not to suck-blow away your gas coverage . they are right about the galvanize fumes. I've had the "metal fume fever " - "zinc chills", & it'll mess you up for 2 or 3 days. NO fun. in my opinion, the best way to weld galvanize is to get some other sucker to do it
04-27-2006, 04:45 PM
After much frustration attempting to patch a pickup bed, a friend with skills set me in the right direction. On my Lincoln Weld-Pak 155 (with gas kit), he had me run the wire as slow as possible (2-3) and the heat as high as possible (C)with out burning through. I also made very short beads, less than 1/2" at a time and spread them out so to not put too much heat in any one area.
Regardless if he was right or wrong, his advice worked great.
04-27-2006, 10:34 PM
Few thoughts and considerations. Especially since you stated 14gauge which seems heavy for auto body unless you are lucky enough to be working on a '50 GMC pickup. :)
But if both existing and new are 14 ga (.0747") you've got a lot room to play. Do you think it's real hot dip galvy or just zinc electro-plated? Even hot dip can be done under varying temps for varying depths of penetration. Any way blather aside, if it's 14 ga you'll wanna flap or buff off the coating in the area of the weld. Will make the whole process a lot easier and solve several problems. Re-coat with a good primer after.
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