1960 Shasta Airflyte

[crowelle]

chaskashasta.blogspot.com/

[vikx]

Thanks! Great Blog!

[cowcharge]

Ditto, nice blog!
A little Bondo and sanding would cover that patch better than a vent that doesn't do anything...

[crowelle]

I've never worked with Bondo before, but know that it is used a lot in auto repair. Is it workable like Sheetrock mud? I would want to mimic the shape of the siding, including the seam. Does it stick to existing paint or do you need to sand down to bare metal? How does it sand? You've piqued my interest!

[cowcharge]

Bondo's great stuff! A plastic spreader works best to apply it, they sell them that is the same color as properly mixed bondo, so you can tell when you've got the right amount of hardener in it. It's harder than mud, which makes it better for the outside. it sands well, takes paint well, and yeah, it works better if it's bare metal, but as long as it's roughed up it should still stick (if it isn't a really large, thick heavy patch). I used it to fill the hole when I moved my water tank filler. I used an aluminum auto-body screen patch to fill the hole, but you already have a metal patch so you don't have to worry about that part. I haven't done the finish sanding yet, but you can see how I did the siding contours on my trailer here, a little over half way down the page. I would do things a bit differently than I did if I were to do it again, I summarized that at the end: vintageshasta.proboards.com/index.cgi?board=shastaownersrestorations&action=display&thread=648&page=3

[crowelle]

You've convinced me! Your patch is amazing and obviously you've proven that the stuff can be sanded and worked to match a profile! I am blown away by how good your patch is! Thanks for the suggestion. I can't wait to try it!

[cowcharge]

It's goopier than mud IIRC, which makes it messier, but also easier to smooth out with the scraper. Make sure you force it under the edges of the metal overlap between the skin and the patch, having it mechanically "key" between the two metals makes it much stronger. And the closer to the final shape you can get it when it's wet, the less sanding you have to do. It is a lot harder than mud, but sands finer because of that. So try to scrape it into the two faces on either side of each groove while it's wet, so most of your "below grade" sanding is already done. Using some of it to make a practice patch on an old piece of skin would be a great idea.

It's a lot harder than mud, so it takes a lot of sanding. I used the front edge of my palm sander to do the contours, and as I said I haven't finished it yet, but it's tricky to get just right, sanding in a "V" like that (especially since my '76 has the multi-groove skins, with 4 or 5 grooves and ridges in the space of four inches or so). You kinda have to do the bottom face of the groove from the bottom, and the top face from the top, because a padded sander doesn't give you a really sharp, flat "V" point to work with. My grooves were turning out to be "softer" than the sharp metal grooves, because the padded part on the sander was digging too deeply into the face of the grooves, before the too-blunt edge got to the bottom of the groove, if that makes sense.

I'm planning on making a sanding block out of a long, sharp, wedge-shaped 1 x 2 and finishing the sanding by hand, like the drawing. A foot-long 1x2 that's ripped on an angle to have a sharp bevel on the long edge (a bevel that's a much narrower angle than the grooves in the metal, so it can sand one face of the groove at a time, and reach the bottom of the groove without taking too much off the face), with sand paper wrapped around it. The long edges outside the sandpaper will bottom out in the metal grooves when you've sanded down far enough, and keep you from going too deep. I'll probably put a second 1x2 on it to act as a handle. Take it down fast with something like 80 or 100 grit, then finish it with 220 and 320, or even 400 and 600 if you're aiming for a great paint job.

Just like sheetrock mud, if you don't fair the edges of the bondo into the metal well enough, you'll see the "seam" when you paint it.

It's hard stuff when it sets up, so when you're applying it, try to scrape it as close to the final surface as you can, to minimize the extra bondo left behind, less sanding that way. If you have a lot of extra on there, after about 20 minutes of set up time but before it's really hardened, it's hard enough to take the worst excess off with a wood rasp, like grating hard cheese (depends on the brand, it says on the can if you can do that, at least on the stuff I bought at the VIP auto store, it wasn't Bondo brand). If you sand it close and do a good paint job no one would notice but you, unless you point it out. As good as my carefully-shot pic might look, it's really obvious in real life that mine isn't done yet, lol. The good thing about bondo though, is you can add another layer and do it over if you sand too deep. Good luck, it's fun, like doing sculpture!

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