Frank, A good top-coat for protection from the sun and weather are the 'clear-coats' used by the automobile industry. Virtually all new automobiles are finished with a 'clear-coat' over a 'color coat'.
'Clear-coat's are manufactured by all the major paint companies. I use DuPont's 7800S. There are several after-market clear-coats out there that are much more affordable and seem to work fine. The most permanent finish for your project would be to coat the sundial with West System epoxy over the paint (two-coats, rolled on) and then two coats of 'clear-coat' over this for ultra violet protection. Charlie Mead 136 Emerald Cove Lane Rockwood, TN 37854 (423) 354-1993 35.85 N. 84.69 W.
