I am trying to weld in a new rear drivers side floor pan and I can't get my welder set correctly. I am using a Powermate 225amp HD mig welder. What wire speed and heat setting would you recommend to start out. I can weld the big stuff but I can't get it to work for nothing! May have to let someone else do it.

I've tried .025, .030, .035 wire also.

Thanks

[This message has been edited by 67_velle (edited 10-23-2000).]

I'm not familiar with that particular brand of welder so lets just talk basics. First be sure you are cleaning all paint form the parts being joined, make absolutely sure you have a good ground, make sure your machine's polarity is correct for mig welding, get a couple pieces of scrap the same thickness as your floor pan and practice on that. What size wire are you using? .030/.035 mild steel wire would be best. When setting your machine on the scrap pieces try different wire feed speeds at each amp/voltage setting. To gain some feel get a heavy(thick) piece of metal and turn your machine up and try different wire speeds till you see the effects then work your way down to the thin stuff. Hope this helps! Remember your eye protection and gloves!
If you do get the machine set right don't try to make a continuous weld but make a series of spot or tack welds then come back and weld in between them. This will help reduce shrinkage/warpage. In fact, once you get the pan tacked down good you can use a good seam sealer on both sides of the floor pan and not even weld it all the way around. I would also recommend hammering around each tack wedd to make the 2 pieces fit better/closer which will improve the fit for welding or sealing.

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Life aint easy when you're fat and greasy!

[This message has been edited by Big James 4XL (edited 10-23-2000).]

[This message has been edited by Big James 4XL (edited 10-23-2000).]

Welding sheet metal should not be that difficult to do. Like in the post above you will have to weld a 1/4" at a time. I would use the .023 mig wire and start with the lowest heat setting first. Try some scrap pieces first until you get the settings right. I used a 110 volt mig welder and you still burn holes if you try long welds.


DON

I'd use the smallest wire. It will melt without burning through the metal as easy.

Try holding the gun at the angle you will weld at with the trigger pulled agains a piece of scrap and then adjust the speed knob until the arc evens out. If it burns through really easily, lower the temp and adjust again.

I've welded 2 quarters onto my car and still don't have the full hang of wire welding. It takes a lot of practice to weld that thin metal. I used flux cored wire though, which is supposed to be harder to weld with.

I think Dave, who owns the body shop I often visit and is great about discussing how to do body work, has his welder set at about 10:30 on the heat. I'm fairly sure his welder is the same as yours (at least it's a Powermate too). I'm not 100% on the feed.

Peter

[This message has been edited by Peter F. (edited 10-23-2000).]

First off, I'd have to agree with the .30 or .35 wire. It's small enough to work on sheet metal, but is also big enough for frame repairs. (why buy a seperate spool for each) I've repaired the whole trunk and the floor in front of the passenger on my '65. When I got the piece cut to fit,(tight as possible without overlap) I placed a tack about every 6 in. around the piece, then one between each of the previous tacks and so on until there was about a half of an inch between tacks. Then I ran small beads to connect the tacks. I had to keep the distance on the tacks at first to give ample cooling time. I would strongly suggest gathering a bunck of scrap pieces the same thickness and do a lot of testing. You should break-test some of your better practice welds for proper penetration. (clamp on one piece and break at the weld, if the weld broke not enough penetration, if you pulled apart metal your doing good) Once you get your machine set right, take some white out and mark the heat and wire speed for easier use in the future. Good luck on your repairs.

Brendan

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'65 SS 355/700-R4
'66 396/T-56 (if I can find one cheap)
'58 Chevy truck bits n' pieces

Thanks, I knew ya'll get me going. I'm going to work on it this evening.

In addition to all of the above suggestions, you need to tune the welder by sound. A proper combination of heat and wire speed should sound like bacon frying. A nice smooth crackling sound. Or buzzing sound. Also set the heat first at a relatively low temp and adjust the wire speed. Usually, the wire speed is easier to tune by.

i think you'll find .023 wire & 70 amps a good place to start as a beginner --- please say your not using flux core !!!!!!

No flux core, on the gas. This is the hardest thing I've tried to do, I guess I'm not a body man.

Im using flux core and havent had much luck is it that hard to use it's all I have $$$ any help you can give much apreciated

Flux core wire works fine if you have the correct alloy for the job. Check withyour supplier to see if you have an alloy for mild steel or for mild/galvanized steel. In some cases the wire for galvanized steel will work better. Also remember to get the polarity correct for the process you use; NEGATIVE polarity(negative output= ground) for FLUX CORE; POSITUVE polarity(positive output= ground) for MIG WIRE. Your wire speed is also very important, and unfortunatly some less expensive machines have an unstable wire speed that will kill you on thin gage metal. Make sure you have a good ground on both parts being joined! Thats why its important to grind/sand edges to bare metal and clamp them together. And by the way, if it was easy your sister would be welding(although I have seen some outstanding welders who also were women).

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Life aint easy when you're fat and greasy!