> Have you considered heat-shrink Dacron? Since you're from Oregon, you must
> know that the war with mold spores is one we cannot win. I've given up on
> canvas, genial mold-host that it is. Dacron is cheaper than canvas, and
> easier to use since you stretch it over the frame as well as you can then
> run an iron over it, magically eliminating any remaining wrinkles. It can
> be painted, urethaned, rolled with epoxy (and painted) or even sheathed
> with more fabric (eg xynole) and epoxy. Source:
> http://aircraft-spruce.com/main.html

I've had my canvas covered yak sitting outside (under cover) for 4 or 5 years now and I don't have mould or mildew on the inside. I attribute this to the use of a well thinned zinc primer used as a base coat to be absorbed by the canvas. I also live in the Pacific Northwest (even wetter than Oregon) where we are expected to get 2 to 3 inches of rain today!

Bram