I've had an opportunity to use bondo recently, though not on a skin
repair. I recently removed, fiberglassed (with cloth and epoxy), and
painted our shower pan. There are a couple of types of bondo: one with
fiberglass reinforcement and one without. The fiberglass kind comes in
two different chop lengths- "kitty hair" is the long strands (~1-2"),
and I can't remember what the shorter shop is called. The fiberglass
strands act as a terrific reinforcer, but makes the material difficult
to work with. For anything less than a 1" hole I certainly wouldn't use
the kitty hair. It's kind of like trying to trowel smooth a fur ball
mixed with Elmer's glue (sorry for the visual..).
If you do use the short chop for it's gap bridging and strength
characteristics, be sure to buy some of the non-glassed material to do
a finish coat with. The fiberglass does not finish by itself to a
smooth, paintable surface.
Regards,
Chris Koehn
'79 @ 31' Int'l
WBCCI 8638