I need to replace quarters on a 70 cutlass. Rust around the wheel opening and bottom edge below trunk on both sides. I have OEM quarters that were cut from donor cars for both left and right.
I have been game planning where to splice these in. The quarters I have are cut just below the factory seem so can't splice at factory joint. Im trying to save as much original metal as possible and dont want to go above body style line on rear quarters. Ive done quarters on a 71 convertible and spliced right below top edge of trunk and didn't go beyond that. Ive been told to stay close to body lines.
If Im butt welding them does it matter? I was thinking of cutting a straight line all the way from front to back or a curved cut to join right below the style line. Im trying to decide which is better and why? Do any of you body guys or anyone for that matter have an opinion on this?
Ill include a pic as an example. BTW not my car in the pic.

 

Can you post a pic showing one of your donor quarters?

 

standby

 

I am no body expert by any means, but I did the quarters on my 70 and turned out good (but my conv is easier seam to do). Even though your donor quarters were cut below factory seam (unfortunately), My gut feel is to weld below the factory seam area. This assumes they were cut at least close to factory seam (like a couple inches). Then, this would only be a 12-15" seam on roof sail panel versus a seam on the whole length of the quarter if you were to cut at those other points. I think it would be best to minimize the seam length to minimize any visible waviness or imperfection if paint shrinks over time or when looking close in sunlight, etc.

As Patton said, let's see where the donor quarters were cut and that will dictate people's recommendations (i.e. if they were cut much lower)

 

How good are you at this kind of body work and welding sheet metal?
IMO a butt weld is better long-term and potential for a better finished product, but a flange weld is MUCH easier to get installed and MUCH easier to get an "acceptable" to "good" finished product. You have very little room for error on a butt weld, so the mud work gets much thicker if things go poorly. IMO the worst part of flange welds on quarters is they're obvious in the trunk, so it's a depressing reminder every time you look in there. I assume the car will be babied, so the rust aspect of flange welds isn't that big of a deal.

I've completely ruined panels using both methods, so I'm an expert. Fun learning experiences, but I ended up hiring out that kind of work. Building up the skill set is pretty difficult. I keep my booger welding to exhaust, mechanical and making tools, so I'm deeply impressed with anyone that can do this stuff.

 

These are the quarters Im working with. I still have to separate some stuff, one more than the other.

 

You basically got the full QP on the P side.....so USE the whole thing. They cut it just below the roof lead seam. The install will be MUCH cleaner using the whole thing. You'll only have a weld seam on the sail panel right below the existing lead seam....VS.....a MASSIVE amount of welding/weld bead and all the associated warpage, etc using your drawing in the first post.

Using the full panel results in a FRACTION of weld bead on any "outer"/visible surface compared to your drawing. Sure, you will have a lot of spot weld cutting and plug welding to do BUT again, the end result will be VERY close to the factory look/method.

AND......you don't have to worry about what the INSIDES of the QP's look like which you would in the case of your drawing.

I'd make the same argument on the D side QP....although that is an obvious NOS QP used to repair whatever car it came from.
Warpage will be more of problem on that side as the seam is lower down the QP and the metal has less stiffness there b/c it's a "flatter" and longer contour down there. Looks like they lap welded it on.....I'm not a fan of that method. Still, I'd go that way any day of the week compared to your drawing. You'll get some idea of what to expect on the D side QP once you remove the paint on top of the lap weld seam and see how much filler was used to get it smooth.

Again, you have two nice donor QP's......make the fullest use of them possible is my opinion.

 

I agree but struggle with the idea or even chances of removing the quarter at all spot welded points and effecting all gaps at door, window and trunk when all are good right now. Ive removed door skins and rebuilt fenders but this seems pretty invasive especially the spot welds on inside of rear passenger side. I hate doing unnecessary work or possibly making things worse. Ive seen so many skin replacements and patches on this site and elsewhere but yet to see a full quarter replacement. I also thought about the back side of the weld and in both possible cuts they would be accessible. I would plan on a butt weld where possible. I also notice the factory seem up near the sail panel is a lap joint spot welded then leaded over. Like you said, it seems one side more of a full quarter and the other a kind of a skin?
Appreciate your opinion.

 

Somebody cut down a full NOS D side QP to make the repair easier and quicker is my bet. They didn't want to mess with the area where the QP is near the end of the drip rail, etc.