It would depend on how much pressure the shrink wrap produces as it shrinks. Some shrinking materials will reduce in size nicely but do it without creating much pressure. For example the heat shrink used on wires is easily stretched when warm. This means that it will shink down until it touches the wire but once the wire is pushing back, it stops shrinking. I would expect shrink wrap to work the same.

> I had another idea for a poor man’s vacuum bag technique that might avoid
> some of the problems you are talking about.

> I have always been fascinated with shrink plastic that is used to seal
> windows in the winter or the heavy duty stuff that is used to winterize
> boats. The stuff seems to shrink in all directions removing wrinkles and
> providing a fair amount of pressure. It seems that you could accomplish
> the same thing as a vacuum bag on the outside of the hull by wrapping the
> peel ply and bleeder sheet in shrink wrap and shrinking it with a heat
> gun.

> With this method you are not drawing air out of the wood or leaving it in
> an evacuated state that could draw in water in the future.

> The only problem I could see is that the heat to shrink the wrap would set
> off the epoxy too fast before the pressure would bleed out excess epoxy or
> do it’s job. As far as doing the insides vacuum bagging seems to be the
> only way to do a concave surface.

> Any comments?

> Jack