Recommendations and Lessons Learned
While building the Foamee, I learned a lot about fiberglassing,
and a little about boatbuilding. Compared to traditional wooden
boatbuilding methods, fiberglass is much faster and requires
much less skill. It still takes a lot of time to get it right,
though, especially the endless loop of sanding and fairing.
If I were doing it again, I would not use any Bondo or other
ready-mixed fairing/filling compound, since I think these are
made entirely from silica or similar products; this adds a lot
of weight and creates hard spots that sand with much more difficulty
than the surrounding foam. I might try building a stitch-and-glue
rowboat using foam with one side pre-glassed, or even with a
foam-marine ply-glass combination. It's much easier to get a
smooth surface by fiberglassing a flat panel on a smooth table
(for instance, a table covered with a formica laminate and then
waxed with a mold release product) than it is to glass a curved
hull, and vacuum-bagging is possible for smaller flat panels
and a shop-vac where it's not possible for an entire hull. I
might also try building another Foamee with a more flexible foam
such as Airex, maybe pre-glassed on one side. If you're building
from a stiff foam like Divinycell, it's probably a good idea
to buy some sheet styrofoam and build a box in which you can
heat the foam with a hair dryer or heat gun, because it's tedious
to heat a single sheet at a time and the foam is easily scorched.
I wouldn't use CSM (mat), even on the exterior. I didn't find
that the exterior was any easier to fair than the interior.
The mat adds some puncture-resistance, but probably not as much as
another layer of glass would have. Its fibers are short and it's
mostly resin, so it adds a lot of weight.
Use peel ply! You will end up with a much lighter boat because
you won't have to add multiple coats of resin to fill the weave
of the cloth after glassing.
I would spend more time fairing the bare foam before doing
any glassing. I should have realized that the glass is a small
fraction of an inch thick, so the final surface is only going
to be as smooth as what's underneath. Don't be afraid to sand
away high spots in the foam or fill dips with gobs of filler.
You probably want to use a higher portion of silica when you're
filling areas before glassing, though, because filler beneath
the glass is structural and must be at least as strong as the
foam, while filler on top of the glass is cosmetic and can be
almost entirely microballons. On the other hand, be careful that
your filler isn't much denser than the foam because if it iw,
you will have hard spots and cavities in the foam around them.
If you want a good-looking boat for the least amount of time,
build a stitch-and-glue boat from marine ply (like the RowMe
or the 8-Ball)
and glass the entire outside with 3 to 4 oz "deck cloth".
The hard chines of stitch-and-glue can make a boat somewhat more
stable and only very slightly slower. If you want the the best sailing
boat, build the Foamee. |