> BTW, what is the reason for recoating with varnish every year
> or two? Are the UV inhibiting properties "consumed" over
> time, or does one recoat mostly for cosmetic reasons (scratches, etc.)?
>

In my case I find that the varnish starts to flake off about 2 or 3 years after it is applied. I suspect water enters through scratches, and a combination of this moisture with exposure to sun and heat eventually weakens the bond between the varnish and the epoxy. If the varnish wears off, then the UV protection vanishes, too.

Paul Jacobson