Should one fibreglass using epoxy or polyester
resin over
wood. In this case it was to join the plywood panels of a
stitch
and glue boat.
First,
Woven fabric will give a smoother finish than chopped strand
matt and is much stronger for the same weight. It also
requires
less filling of the weave to get a smooth surface.
If you want the boat to last a long time I would be using
epoxy rather
than polyester.
The polyester relies on going a little way up the cellulose
tubes and hardens. Just sort of tangles up.
The epoxy tangles up the same way but ALSO joins onto the
molecular
structure - much stronger. It actually joins onto the
molecular
structure of the
cellulose (hydroxyl bond) which polyester doesn't.
One of the sad moments in my boat repairing life was after I
had used
polyester resin to fibreglass a boat's deck. The owner came
down
the day after the 'glass had been resined and said it looked
nice. He then noticed a thread hanging out the edge and gave
it
an unconscious pull. Half a metre of the cured surface tore
off. Back to the drawing board!
Epoxy IS more expensive but does a much more permanent job.
But if you just
want the boat for a couple of years and then are happy to throw it away
polyester will probably be OK and
will save you money.
Sometimes polyester does stick OK to wood, but it is not
reliable.