Quarter panel patch shape

[Chevyman for life]

Looking for some experienced thoughts on patch panel shape. I am about to replace the flared rear wheel openings with stock openings on my '55.

As shown in the attached photos, the openings were cut above the normal rear quarter trim strip. I can't afford new quarters so I got two 4 door pieces cut from a solid, rust free '55. There's a lot of bondo at the weld seam but it's stitch welded or spot welded so I'll have to see what shape the fender is in but I can cut above the previous weld.

Other than the dog leg I can cut a large retangle or I can cut up, then at a 45 deg angle, horizontal, down a 45 degrees and then down vertical. My question is whether one method is better than an other as far as less warpage. I'll be using a MIG with Argon mix and spot welding back and forth.

I'd appreciate any experienced ideas.

[Rick_L]

The same question was asked in bit of a different context a while back. Since the crown in the quarter is primarily vertical and the quarter is pretty flat horizontally, it's probably easier to see where your warpage is if you keep the cuts either vertical or horizontal. Actually that may be more of a picky thing than needed.

There is a big exception to this. You don't want the cuts and welds to meet at a square corner. Put a pretty big radius on all the corners of your cuts and welds. This part is more important.

Last thing, if possible, make your cuts and welds inside the wheel house if possible. This will let you get behind the panel with a dolly to stretch the shrink out of the weld joints. This is very important. See MP&C's post from a week or two ago on patch panels, stretching to remove weld shrinkage etc.

If the original cut is close to the wheel house, you may want to remove it temporarily.

[Chevyman for life]

Rick,

Thanks for the advice and the other link to Robert. When you say a large radius at the corners how large do you mean? 4" radius or larger? The wheelhouse doesn't look to be a problem.

[Rick_L]

4" radius would be pretty big. 1-2" would do it. You just want to eliminate the square corner.

[pistoncan]

I think Rick is correct, you can also just nip off the corner to make a 2 inch 45 degree flat. My dad said to make your patch panel, then mark and cut your fender to match your patch panel. Don;t try to make your patch panel fit the hole in yoiur fender. You will run out of patch panel alot sooner than you run out of fender.
Gary