I want to make a 3"square canvas sheet to roll some gear in and tie to the back of a saddle. Would like to make the canvas as water repellant as reasonably possible, but wouldn't want it to be greasy or waxy.

I've used Thompson Water Sealer in the past... and it is sort of o.k. Just read about another treatment:
3c Soybean Oil mixed with 1 1/2 c. Turpentine, paint on and allow to dry. Does anyone have any experience with this stuff? Does it actually dry. I guess I could try it, but thought I'd mine the Forum minds first.