I have a really simple question what is the best way to attach the new trunk pan to the existing trunk pan? (over the rear axle under the package tray) should i overlap it? or crimp one of the pans and lay the other on it and spot weld? :confused:

....??

Originally posted by Tomb7us:
....?? Over lap it. it will be just as strong as a butt weld. I finally got it one day.... the Chevelle is held together with nothing more than a gob load of spot welds and seam sealer. You will be fine with the overlap welds.

Tom,
I believe a lap over is good for your application. I would lay in the new pan, use a felt tip marker to identify where the new pan extends up into the hump area. Remove the pan and cut below the line, leaving 1/2 to 3/4 inch. This is sufficient for a lip. Once you complete the cut and remove the rusty pieces, sand the area where the marker line is for good weld conductivity.

I would lay a bead across the entire length. Probably lay 1 inch, skip an inch and lay another inch of weld. Once things cool down weld up the 1 inch gaps.

Sand down the bead on the inside of the trunk to reduce visibility. Prime the bare metal surfaces and the weld area. Once dry, apply seam sealer to the seam area inside and to the underside to prevent water trapment. Then you are ready to spatter the trunk.

Just on the other side, if you are going for the best result ( read: cleanest ) result, I would have it butt welded.

whats the best approach to butt welding it?

This metal is difficult to butt weld. You have to back it up with a piece of brass or you'll burn through it. The problem is getting to the bottom of the pan when you're trying to weld the seam. Unless the body is off the frame, there are some places that are impossible to get at.

An alternate method is tack weld a narrow strip of sheetmetal to the backside of either the existing metal or the new pan. Tack the strip along the entire length of the seam you're welding. When you get ready to weld the two pieces together, the sheetmetal strip provides a backing for the joint to keep from burning through. It'll become part of the car, so you'l have to seal it up from underneath when you're done.

If you lap it makw sure the seem is facing the right way. If you have it facing towards the front it WILL collect dirt, moisture what ever.
So when you lap it, place the NEW metal OVER the old metal.
This will create a seem that doesnt collect dirt.

allright thanks so much guys after i overlap this will you be ever to tell very easy?