Hello - I am refinishing a custom wood canoe paddle. I am first applying a fibreglass cloth/epoxy over the blade for strength as its a white water paddle that sees frequent use. I'd then like to apply a Epifanes matt varnish over the blade.
Will there be any issues applying the Epifanes over the epoxy? I plan to allow the epoxy to cure for about a week, then 220 sand before applying several coats of Epifanes. Any advice appreciated, I have heard that applying varnish over epoxy can be tricky.
You will require several coats of the Marine Clear Varnish before applying the Matt.
The Epifanes Marine Varnish will work very well over epoxy, but certain precautions must be observed. I'll detail them.
All marine epoxies exhale a chemical called 'amine blush' which is a sort of waxy residue of the epoxy's curing process. Some epoxy makers claim their products don't develop this, but our experience is that most do, to a greater or lesser extent. Amine blush will prevent any subsequent coating from properly drying. Here's how to prevent that from happening.
after the last of the epoxy coating is applied… wait a week for it to thoroughly cure. I know that's longer than the makers suggest… but safe is better than sorry.
before any sanding is done, wash the epoxy with warm soapy water and a sponge, then rinse the soapy water off with clean water and let it dry.
only then, sand the surface of the epoxy with 220 grit or something near that. Sanding before washing can be bad because if amine blush is present, the sanding will grind the waxy blush into the surface where it can be very difficult to remove.
proceed with varnishing… there is no need to deeply thin the first coats because the epoxy will prevent the wood from absorbing thinned varnish. The first coat can be full or nearly full strength.
keep in mind that while the epoxy can strengthen the wood of the boat, it contributes nothing at all to UV protection, and must itself be protected from the sun, so the normal minimum of six coats of varnish for new work must be applied.
