Maybe I haven’t stated this succinctly enough, but from my Aerospace Industry background
I can tell you a helpful hint one more time…
Epoxy can reach a hardened, handle-able state, but not be fully cured. You can surf a board
that is not cured. When not fully cured, epoxy will feel kind of firm, like the same hardness as
polyester resin on a low-density blank.
It is extremely desireable to get the epoxy change-of-state reaction to go as fully to completion
as possible, since epoxy can be as much as 4 times stronger than polyester (depending upon
brand and type of wash on the fibers).
Here is what we found happens:
If a board is made in a good epoxy temperature (say, 80F) and is not allowed to drop below this
temp during the entire construction, maximum strength is more likely to be approached. Letting
the temp fall at any phase of the build will compromise this chance. For example, if you glass the
bottom in a room at 80F, then decide to do the deck the next day and overnight the temp drops
to 65F, you will most likely not get near max strength- even with post-curing.
On the other hand, if you glass the entire board at a good temperature then go directly to post-cure,
then you ensure doing the best in getting a truly good, strong product.
This is why we have a digitally controlled oven that holds up to 8 boards. I am a proponent of doing
a board in one session. Flip times are about 45 minutes. As a note, we started doing the “Brazil style”
of laminating where the board is flipped at the onset of B-stage. Literally ‘wet to the touch’ but tacked
in place. The deck is lammed without any lap prep needed. This maximizes strength of the rails. We
have photo sequences of this being done on our website under the New Tech section.
One caveat is the deck lam must go to B-stage before going into an oven that is more than 5 degrees
above ambient. If the room is at 80F then B-stage will be reached in less than 20 minutes, so the
oven can be at 105F without having any blowouts.
Hotcoats seem to take slightly longer than lams (due to film thickness/thinness?) but still are reasonable
for a one-session build.
Arid weather like in southern California takes away from the effectiveness of heated rooms. This can be
as much as 10F.
Post-cure of 4 hours at 105F appears to get very noticible increases in strength. Our sander does not
like sanding post-cured boards so we are working on that one while still getting the max strength.
Anyways, sorry for crapping on, just trying to help. Even here in southern California, heed these warnings,
otherwise you are facing a long winter of learning… (or you don’t mind soft boards)
