Cutting Scrap Bodies for Patch Panels - Your Preferred Techniques & Hints Please

[impcon]

So, I have a question that I am sure others can benefit from learning the answers to. One of my current projects is an old SMP or Craftsman Series '59 Impala convertible that I bought off Ebay several years ago and I have been working on along with a matching SMP hardtop. The convertible came out very clean after the paint was removed but the lower quarter panel between the door and into the rear wheel opening has a fairly large piece broken out of it and no, I do not have the piece that is broken out. I got lucky and scored another identical blue convertible on Ebay that was mangled beyond hope when some smart person decided to make the car look like it had been hit hard on the passenger's front corner. The windshield frame was broken in the center but I managed to make a repair to it that will be invisible once it is foiled. The rear part of the car however is very nice and clean.

I want to ask someone who has done this before what your suggested technique would be to remove the broken quarter panel and replace it with another. I just cut some lower body pieces out of a '58 Ford and replaced them with parts from a much newer AMT '57 Ford and that seems to have worked out well. But this is a much larger panel and I think it best to replace the entire lower rear panel beneath the side trim and right to the back of the body where a seam or joint will be easily hidden. Am I wrong in your opinion, for using this approach as opposed to trying to section in a smaller section with the compound curves of the rear wheel opening? I plan to glue some .020 x .250" strip styrene along the inside of the body of the builder and use that as the guage by which to match up the panels and the main means of attaching the patch panel to the body as I did on the '58 Ford.

Also, which cut do you recommend making first - the parts car or the project? I am thinking the project because it should be easier to fit a patch panel that is a bit over sized as opposed to one that may be a fraction of an inch too short. I use a combination of liquid cement and tube glue - liquid on one panel and tube glue on the other and that technique seems to give me a very good bond that is much stronger than using just tube or liquid cement on a repair or joint. I would think that CA glue will not allow enough time for the fiddly last second fitting. What are your thoughts?

For finishing the joints where the two pieces of plastic come together, I'll use Squadron White Putty - or do you suggest something else that works better for you? I know that I can do this, but I am asking for input from others who have done this more than I have and hopefully some extra knowledge based on experience will make this go better with a nicer finished project. I can post photos of both cars if they will clarify what I am trying to describe and give you a better idea as to exactly what I am doing. Sorry to seem like a dummy, but as I have said before, it's better to walk through a mine field in the steps of someone who has already traversed it than try to do it yourself by feel and ear. Suggestions as always, are appreciated. Thank you in advance.

[Ace-Garageguy]

Gary, I noticed you recently checked in on my Phoenix project over at http://www.modelcarsmag.com/forums/index.php?showtopic=58538. The nice thing about the f'glass technique is that you form the new part right on the car, using the mold you made from the donor. That's my preferred technique.

This has the two advantages of 1) letting the new part be made in absolutely correct alignment and 2) you don't destroy the donor in the process.

BUT...If you need to replace a large area and elect to splice in good styrene from a donor, it's easier to replace an entire quarter panel or fender, where the seams can be hidden on door cut-lines, etc. Just like on a real car, you don't have to get into making, shaping and finishing splices in the middle of a panel, so doing a much larger section is often much less work, with better results.

If you have a smaller area, say just the lower rear section of a quarter panel, cut your donor a little oversize from what you think you'll need. Neaten the edges up, and then trace them VERY carefully on the body you want to repair. Make your cuts undersized on the receiving body, and slowly file to fit your patch panel exactly.

I agree that using liquid glue or the combo you've mentioned is better than using CA for the initial placement. Once you get some practice doing these splices, you can pretty well gauge how much your seam edge will "melt'in" when you glue it, and you can get just a little molten plastic squeeze-out as you put everything together. Be sure to let it dry COMPLETELY (and be sure to check your alignment carefully before it sets up; the glued joints like that become quite strong).

I also often use plastic strip "guides" on the back sides of joints to get panels aligned, but I also usually remove them after the splice is completely set-up.

Even when splicing styrene panels in, I usually use fine fiberglass on the back of the splice for strength. Running a bead of toughened CA (like Loctite Ultra Gel) along the outside of the seam has worked well for me too. If you fit your parts closely enough, you may not need any additional filler.

But if you DO need filler, I'd tend to use a 2-part polyester like Bondo Professional Glazing Putty (avaliable in small packages, cheap) The one-part putties like Squadron shrink (in my experience) and eventually, you'll see a seam ghosting through your paint.

Edited November 26, 2014 by Ace-Garageguy

[Cato]

Bill covered it very well; I'd just add, forget the Squadron.

For anything thing that requires fill use Bondo Professional Glazing and Spot Putty. It's two part, dries in 1/2 hour (or depending how much hardener you mix), sands to a feather and NEVER shrinks.

At your auto parts store, about 8 Bucks.

[Snake45]

Another thing you can do if you have a good body is pull a female mold of the desired area off it using silicone caulk, cut the damaged area out of the "bad" body, put the silicone mold right on the body you're repairing, and fill it from the back with epoxy. This is called "sili-cloning" and I've done it several times with good results.