One for you guys that have replaced a panel or two...
They say to use a stitch pattern so as not to overheat and warp the steel. Continue jumping around the outer edge until it's all welded in but does it have to have weld on every bit of the perimeter?? Or can you just do most of it and then grind it off and fill it?

Here's what I did with my passenger side partial floor patch.

Tacked it in and then used seam sealer around the rest of it.

It depends if you want the patch visible or not. You'll have seam sealer in areas which are visible if you did the same area the Dr. has. If you don't want it to show, then a butt weld is the path to take finished with a grinder. The latter is more work though.

Butt weld it will be but I'm not sure if it needs to end up having a continueous weld around the perimeter or a if close stitch is good enough before grind and fill. It's a fender patch.

When it heats up thro cold water on it to help it shrink into a tight patch with little or no oil canning. Body shop buddy showed me that works awesome for smaller patch panels..

Your talking about filler and plug welds for a fender. That's a different animal.

I was referring to floor work, and I plan to not have any overlaps unless they were original to the repaired area as the Dr's picture reflects. He stitched on both sides of the overlap. Any tunnel welds for me will be a butt weld with no visible seam.

Hopefully someone will chime in on the Fender repairs.

You should end up with a continuous weld around the entire patch. Think of the process as a series of tack welds. I usually tack the patch in place then altermate tacks around patch. This process will reduce the likely hood of any one area getting to hot an warping. Slow cooling will reduce warping as well. Take a few beer breaks and set up a fan to cool the entire patch..then start the process again. The water method will warp the panel. This is not much of a issue if you are patching a floor, but not so good if you're patching an exterior body panel.

Right u r... doh...

hate to say it; but, please don't use water. it shrinks the metal and that pulls it tight and warps it. also, it will harden the metal to the point that it will crack. i think there is a product that can be used as a heat sink i cant remenber for sure. just go slow. i myself, would finish it complete. because i would fear that water can leak though the cracks on the the new floor even with sealer. that my opinion.

Eastwoods sells a welding putty that absorbs heat just for problems like this.

Thanks for the replies. Of course the answer is what I expected but I wanted to make sure. I may take it to a shop to see how much they would charge to weld it in. Always nice to know how much you're saving doing it yourself. Makes it seem a little more worth the effort while in the middle of the job.
Must be 8 feet of welding to completely do one side. One spot at a time. Wonder how long that's going to take?

I just did a full quarter butt-welded just below the top body line. All said around 6 feet long plus another 4 feet or so for the seams at the door jamb and the bottom to meet the rocker. Find something else to do around the shop and weld for 5 minutes at a time jumping around filling in the spot weld gaps, probably only 1/2 hour to 45 minutes of actual welding time before you end up with all the spaces filled in.

Grant

You might also check out the cleko clips. They hold the panels at the correct gap for butt welding. Then there is no overlap to deal with. Eastwood sells them.

I have seen pictures of a car with a new floor pan put in, and aparantly did not seal it properly, and began rusting in between the overlaps...not good.

Mark,

If we paid your airfare and had everything set up here waiting for you, would ya replace my rear QPs (full)? I can't get myself to turn my bird over to a shop for 2-4 weeks. Just don't trust people and shops.

I'll pay for ALL your time and work. Nashville is a great little place to spend a few days......