I used the water based Minwax Polycryl on my balsa sheeted foam core floats shown here. Rubbed on a very light coat with a rag so grain didn't raise too much. Laid on 1/2 oz glass to the dry surface and brushed on the poly with a cheap nylon brush ( natural bristles introduce bubbles). I quickened the drying time with a hair dryer. After two more coats I began filling the weave with the poly mixed with corn starch. Three coats of this, sanding between coats made the suface as smooth as a baby's butt. You must seal the cornstarch because some primers may cause it to pop or blister, so two more coats of plain poly to seal the cornstarch, fine sanding and they're ready for primer. I used automotive primer and auto base/clear coat for the blue and then Lustrekote orange to match my orange Monokote. This whole process is fast, could be done in a day with no problem. I have used epoxies for composite layups at work so I know how long the curing process is for that method, this waterbased poly is the way to go for models. I have a set of Goldberg Super Floats ready for the same treatment.