Loosing a Few Pounds

It would seem I've avoided the remaining fiberglass work as long as possible.  The rear of the car has been hidden under a blue tarp in the back yard since the initial demantling several years ago.  It has several of the kind of knicks and tears at the wheel wells and around the muffler cut-outs that one would expect.  It also has stress fractures around the rear hatch hinges and at one rear corner that are due mostly to being a 40 year old peice of fiberglass. However, the portion that consumed my weekend was the drivers side rear fender which (on the surface) doesn't seem too bad.

From the several layers of exposed fiberglass and bondo, and the various shades of primer and paint, it is obvious that there has been major work here in the past, but the shape appears to match the other side of the car and have all the right lines and curves. . .

Until you look at the back side of the panel . . .

For comparison, here is the passenger side. 

The black line in each photo is where the metal chasis mates with the fiberglass, and the grey part is that part of the body exposed to the wheel well.  Aside from the various bits of recycled blue plywood, cardboard, and metal riveted, screwed or otherwise attached to the panel in the upper photo, note that there is a very distinct reveal in the lower photo (near the bottom of the panel) that is missing in the upper photo.

Step one was to remove all the bits and appurtances and determine how bad the original break was.  This is where things started to head south.  After excavating approximately 3/8" into the back side of the panel through what was obviously field-applied fiberglass and body filler I encountered this:

Chicken wire! When fully exposed it looked like this:

Over a foot tall and at least that wide again at the top!  The question remained "where is the original fiberglass?"  So I kept grinding. 

I never did find it - which means someone refabricated this entire section of the body from scratch! 

As mentioned before, from the outside it looked accurate, but now knowing what I was seing I started to notice the small differences.  For instance, the reveal around the wheel arch seemed to be a thicker profile (it had to be to compensate for all that additional filler), and the reveal where the door panel overlaps the fender was only half the depth it should have been (no wonder the door wouldn't close!). 

After all the exploratory surgery was done, I ended up with a thin sheet of pure bondo that nevertheless still had roughly the correct shape on the exterior.

These are the piles of stuff that was removed.  (Well most of it.  There's probably that much dust again laying all over my shop now. . .)

This is what it looked like with a new layer of fiberglass installed.  The blue bits are painters tape showing through where my exploratory surgery got a bit too close to the surface or where rivets/screws pulled through from the original repair.  The large blue patch at bottom right is a piece of tape pulling the end cap into the correct position.

Time for a cold beer to give the new work time to set. . .  Which is when I got the second nasty surprise. 

This repair is by far the largest piece I've had to do to date, which means it's the largest batch of resin I've had to mix.  Apparently I got the percentages off by a bit.  Apparently a large bit.  After 4 hours it still was barely setting at all!  A consultation to my favorite search engine provided the consensus that the mix was probably a bit shy on activator, and it would eventually set.

 

Recommendations were to apply heat.  A propane torch appeared to do little except set fire to the surface if held too closely or too long a time in one spot, so that was quickly abandoned.  So (in spite the fact that it's summer, and 90 degrees F outside) I placed a space heater in front of the panel and waited another hour; which had no effect other than to raise the temperature of the shop to about 100 degrees F.  In disgust I closed down the shop for the night.

The next morning, there was still no progress, so I proceeded with sanding the rest of the rear body.  I also patched a structural tear on the same side where the window pillar joins the roof:

Before

After

After much sanding, the car is starting to look an almost uniform color.  (The dark bits are shadow lines).  I've still got some sanding to do at the front drainage tray, at the rear, and of course at the problem area.  I've also still got to patch up all those smaller blemishes noted earlier.  Still, a marked improvement! 



You'll note that the body is now back outside. The last tip for helping stubborn fiberglass resin to set is to expose the piece to direct sunlight where the UV rays can assist the heat in activating the curing process. Would you believe it worked? When I left for work this morning it was as sticky as ever, but when I got home, it was hard and dry!