Most reputable marine varnish manufacturers refer to their products as 'marine varnish'. very few use the term 'spar varnish'. Minwax used the Spar Varnish' loosely. It is anything but a spar varnish. It seems to have a lifespan in direct sunlight of barely a month or two. It is pure crap. The name of the product is deceptive.
I dont know what criteria some people are referring to when they say spar or marine varnish is soft. Soft as compared to what?
i have lived on my boat/boats for 25 years. The areas of varnish (marine varnish) such as thresholds parts of decking, etc, even my
main salon sole (living room floor) that get walked on everyday, have anchor chains dragged across them etc, hold up for many years if the varnish is properly maintained. I never saw dents in the finish, but I have seen scratches. So I dont know what 'soft' is. Probably a relative term.
Anyway, Helmsman Spar Varnish by Minwax is a joke and other marine varnishes should not be judged in the same sentence with this crap. When a boater, including myself, spends countless hours sanding, scraping and masking the woodwork (brightwork) and ultimately paint the "Spar Varnish" on the boat just to see it disintegrate in well under 2 months, that makes you very mad. Now, it must be removed which also takes a lot of time. so that is why I hate Minwax Helmsman Spar Varnish.
While we are at it, let me give u another nautical term...."Brightwork" is varnished wood as compared to painted wood.
As for expansion and contraction due to humidity, not really too much of an effect because the wood is encased in a moisture proof barrier of the varnish.
The initial application of a marine varnish on a really worn out part of the boat does takes time and maintenance. usually, the first go around takes 8 coats of marine varnish at 2 coats a day in warm - not hot - weather. Annual maintenance means every year thereafter you lightly sand the surface and apply 2 coats. And thats on the coast of the Gulf of Mexico from Florida to the Redneck Riviera where there is too much sunlight and heat. Slightly north of the coast, you can get away with maintaining the finish every 2 years.
Tony B Retired woodworker, among other things.
"Strive for excellence and settle for completion" Tony B
Last edited by Tony B; 11-22-2019 at 05:24 PM.