how do I go about this?

[hit_em]

I've never welded thin metal before and am wondering the best way to approach this. I have an old car that I'm going to weld some replacement panels on and dont really know what I'm doing when it comes to thin stuff. I was told to just drill some holes along the edge of the new panel put them in place and tack them in there then fill the visable edge with puddy and you will never know. Is this the way I should do it or is there another and better way to go about this? any information will be greatly appriciated.

[MAC702]

You don't even tell us what equipment you have at your disposal.

[hit_em]

sorry, I have a Miller 251 using argoshield.

[lowestcerberus]

I try to butt weld the panels. I prefer a .024 wire with c25.

[MAC702]

Use .023" solid wire and a C-25 shielding gas for best results. ESAB also makes a wire called EasyGrind designed for this, also.

Use a series of spot welds, basically manually pulsing the trigger to kep the heat input down while making short beads in many locations until finished. this minimizes blowing through.

Also, use some copper "spoons" behind the weld to absorb heat and contain the blow-throughs. The molten steel won't stick to it. You can make some with some copper pipe hammered flat, if you have to.

When welded, grind to almost flush, and then use a fine flap-disk, two passes at right angles to each other, and you'll have a mirror finish when done.

[Winger Ed.]

What I've done in the past to get a good fit for the replacement panels is to zip a few screws into the new panel on the area it's going, then cut the panel out with a saw. It'll be a perfect fit.

Then to keep the new panel from falling through before you weld it, sheet metal screw a little piece of scrap on the inside of what you're patching over every few inches.

You'll end up with a few little holes around the edges of your weld when your done, but they weld up in a second or two.

The last thing I did that way was both rear corners of a 70 Chevy truck cab that had rotted out. It worked so well I only needed about 2-3 tablespoons of bondo for the whole back end of the cab.


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[fun4now]

biggest thing is keep your welds short and skip around a bit to keep worpage down. even if its welding nice and smoothly you gotta stop or it will blow threw. 1/2" to 1" is going to be the max per bead if you even make that. 1/4" to 1/2" is about right but milage verrys from welder to welder. do a few test welds to get comfortable and get the welder dialed in first, then get-er-done

[hit_em]

okay so you guys are saying that I'll be better off doing a butt weld instead of overlaping the pieces? I figured I would have to keep short little blast's but wasn't sure how to line the metal up together. Thanks guys if you have any more advice keep it commming.

[Sundown]

If you want to you can get a flanging tool (either the pliers type or the air one if you have a compressor) from Eastwood, harbour Freight, or somewhere and flange the existing edge to fit the repair peice and weld it on. The downside is if you can't get to the backside to seal the overlap it will rust easier. As stated, spot and very short (1/2-3/4") welds are best and try to keep them across from each other to keep the heat down. And go slow and take your time.