: This is one of those queries regarding techniques/processes for
: lightweight building.
: I'm currently building a racing craft and a mate of mine is
: building a hollow timber surfboard. His plans don't call for any
: use of epoxy to seal internally and he intends to seal the
: inside surfaces by either painting or using a couple of coats of
: penetrating oil such as penetrol.
: If an internal surface needs to be sealed against water ingress but
: structural strength is not an issue, would a penetrating oil be
: a lightweight (and cheaper) alternative to a coat of expoxy?
: Thougts anybody??
: cheers

Hi Craig,
Not really is my thought. The oil will soak in a bit but not much and enough to waterproof the wood would weigh more than epoxy. A skim coat or two is all that would be needed for the interior of the board, a couple of ounces of weight for a longer lasting coating.
With paint, to get the same waterproofing as epoxy, the paint would also weigh more.

Mike Savage
South West Cork