Refinishing / Refreshing Mahagony Exterior Door with Existing Spar Varnish Finish

[Alan Lightstone]

I’ve got an exterior Mahogany door that is finished with Spar Varnish (not sure which brand). After 5 years in the Florida sun, it’s looking a little dull.



Can I just wipe on a few coats of Spar Varnish (thinking Epifanes), or do I need to strip off the existing spar varnish? Would brushing on be a better approach?


Would light sanding for adhesion be necessary?

Any other better suggestions for freshening up the finish?

[Steve Schoene]

First inspect carefully. If the finish is just dull but is intact without cracks or lifted spots then you can overcoat without a problem. But if the existing finish isn't really sound then you should strip

Make sure the door is clean. Then a light sanding with 320 grit would help assure adhesion whether absolutely needed or not. Then I would brush on the Epifanes. Regardless of the label, you will need to thin the Epifanes for brushing. If you thin enough for wiping on, you will need to do more coats to achieve the same thickness as the brushed on coats. Film thickness matters with spar since only with adequate thickness do you get sufficient UV absorbers for long life.