Have just finished removing the paint on a 5m cat back to bare ply [tedious job!] and would be grateful for any advice on painting.
At this stage I intend to start with an epoxy sealer and possibly a 2 pak system. Would prefer not to have to spray, but will if needed.

Thanks...

Hi M0squito
I hope you were careful while sanding the hulls because sanding trough the outer veneer of the plywood would be bad...
I think two thin coats of epoxy applied with a roller(the type you use for varnish)followed by 3 coats minimum of 2 part polyurethane varnish should do the trick.
You will probably have to let the epoxy cure for at least 3 weeks(longer would be better) before you apply the polyurethane(you can speed up the epoxy cure time up if you keep the hulls in a heated room) , if you don't the amin blush(a waxy byproduct) that is formed on the surface of your epoxy coat will stop your varnish adhering properly to the epoxy. Best way to remove amin blush I have found is to use the green scouring pads people also use for cleaning their pots and pans, make sure you change the water often and wipe clean/dry with kitchen towels. It is possible to use rollers to apply the 2 part pol. but spraying will give you a much better finish. You might consider applying the first two coats with a roller and spray the last coat. Light sanding in between layers gives best results.
Good luck with your project

try searching for "painting hulls" on this website this subject might already been covered by others.

Also, check out websites about plywood kayaks. There is a great forum on the Chesapeake Light Craft Website. They doo lots of finihsing of wood hulls.

Here's the link:
www.clcboats.com

There are some very talaneted guys in the forums.