Marine Spar Varnish can be recoated in 10-12 hours at the recommended coverage rate. The varnish can be recoated without sanding up to 24 hours. Beyond 24 hours, sanding is required. Use 220-320 grit paper for brushing applications. Use 400-600 grit for spray applications.
We are brush applying Satin Marine Spar Varnish to a new epoxy sealed wood kayak. epoxy has cured several months and has been sanded to 320. Expect high humidity at the time of finish applications. Not going for furniture quality but don’t want a finish failure either. Any suggestions on what to expect and remedies for dealing with high humidity at the time of application?
For starters, make sure the surface is clean and free from contaminants.
High humidity can impact the drying of spar varnish type finishes. However, we have seen through the years that System Three Spar Urethane Varnish performs very well in high humidity conditions. Regardless of conditions, make sure to keep the film thickness on the thin side. Thick coats will prolong the cure and leave it susceptible to dust and other film defects.
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