Monday, February 18, 2019

Final LH Rear Wing Repair | Roundtail Restoration

Yes, you heard that right. I finally got that pesky driver's side rear wing repair done. Yes, of course I had done it a long time ago and thought I was done then. But, no, I was wrong. That repair resulted in a huge water trap and I'm sure the thing would have rusted out rapidly. The first re-repair I tried ended horribly. Third time's the charm.

To the video:


I left the last post having gotten just a single, very small patch in to start the process.

Ain't it cute.

I continued cutting and fitting patches, welding them in as I went. In the end, the amount of heat damage was just too much and the panel was just as bad as it was before I cut it apart (though there wasn't a lap joint anymore, so no water trap).

You can see the ugliness. And the shot doesn't do the waviness justice.

Showing the blow-through holes towards the back.

Of course, I couldn't leave it that way. My mistakes were many. Namely, I used too many patches, which meant I had to do a lot of welding. So, even though I was using compressed air and waiting, the metal just retained too much heat and warped. Also, my patches were too small for the total repair area. It's one thing to use a small, rectangular patch for a single area. But when you string upwards of 10 of those together, like I did...well, I should have used much fewer and larger patches.

I stopped that night knowing I was going to give it another try and stewed about it for a few days.

When I got back, my plan was to do two patches, both large compared to the others. Importantly, large enough to cut out my "repair" job and a bit more around that to get all of the potentially heat-damaged metal out of there.

Black Sharpie outlining what will be cut away for the rear patch.

And the outline for the front patch.

The rear patch was going to be the more complicated of the two since it swept up a bit and curved in. The metal twisted around its axis. Fortunately, I was able to re-create about 80% of this shape on the bench and did it in such a way where I could tack some of it in and push or pull other portions of it to get the shape right.

Here's the rear patch. It's curved, but not really twisted yet.

Unlike I usually have done in the past, I made this patch before I cut any metal from the car. This is the smarter way to do it since you can use the existing metal to help you shape the patch. Not sure why I haven't always done it in this order, but if you can (assuming what you are replacing hasn't rusted away to nothing), I'd recommend it.

With the patch made, I cut out the rear portion, fit up the patch, and tacked it in.

The back of the rear portion I cut out. Man, that's horrible.

Rear patch tacked in, front patch cut and fitted.

After getting the rear patch tacked in, I repeated this process for the front patch.

Front patch in, ready to weld.

Once I got the front patch tacked in, I went back and slowly worked all the way around the repairs, get it all welded in. In addition to compressed air, I used a trick I found from a YouTube guy that I subscribe to, Trev's Blog. He's got great videos, obviously does this stuff for a living, and is a wealth of knowledge. To minimize heat damage, he uses wetted shop cloths (no dripping wet, but close), arranged around the weld area, to absorbed the heat. You have to re-wet them as they will dry over time.

It seemed to work okay. I didn't do a control test (no towels) and I did have some heat damage in the end, but it was mainly concentrated near the vertical seam where the two patches came together. Probably a support thing?

The heat sink (?)
 
All welded up.
 
And ground down. Much better.

I used the stud welder in a few spots to pull the metal out and it worked out. The area will need some filler (not too much), but it should be a much sturdier and lasting repair.

With that area done, I moved back to the more mundane body work. The rear sail plate is a mess. Most of the reason, in my opinion, is because it is minimally supported from underneath and only then at the edges. While the gas tank does go under the sail plate, I don't believe it provides any real support.

I worked what I could with hammer and dolly and used filler for the rest. I also got filler on some parts of that rear wing that still had epoxy over them.

The rear sail plate.

LH rear wing in filler. 

And the sail plate in filler. Ran out, so still some spots on the right to do.

I don't put filler over bare metal, only over epoxy unless it's very incidental. Therefore, the next visit will involve blocking this new filler down and then going around to other areas that need work (like that one sill transition) prior to the next round of epoxy.

The repair that I did in this post and the one around the RH tail light are still bare metal, so they need epoxy prior to filler. That means another coat of epoxy after that filler work to seal it in. But then, hopefully, I'll be on to build primer!

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