Digital BW, The Print

Epoxy is unstable in UV environments. It will fail in 1 - 3 years. Mega 
yachts and aircraft are finished with a sprayed-on linear polyurethane 
which REQUIRES the applier to wear a positive pressure filtered air 
supply. In wooden boat building, which I have done, epoxy must be 
protected with opaque pigment or over coated with a UV filtering 
material like paint.

The UV resistant varnishes are a good place to start, I guess. Whatever 
is used, the "many light coats" school is probably best followed. The 
finest will be sprayed unless one has a good hand with a fine (read 
expensive) brush. Perhaps Ultra Chrome will save us all from it; or 
Ilford.

Jim
San Diego