Thank you for your informed answer. Presently I have on this wood project a thin coat of spar helmsman and then two coats of Tung oil Protective Finish over top this
I am wondering if it's worth my while to give it a top coat of Helmsman??
I strongly suspect that "Tung oil Protective Finish" is probably a polymerized 'finish' and not an oil. You are probably not helping any by mixing different finishes like that. i.e. probably not worth your time.
One last question please
What are the real differences Minwax Helmsman (spar urethane in small letters) and Minwax Spar Varnish ??
(Poly)urethane and varnish are 2 different creatures, urethane is basically "plastic" (polymerized) - varnish is (**usually**) more natural being made from resins, oils and solvents.
Generally a varnish will be more UV resistant, where polyurethane ~not so much~ i.e. varnish = outdoor projects, polyurethane = indoor projects.
Caveat: you gotta read the can, how things are made and labelled these days does not grantee what is actually in the can ... see below
Much like Tung oil finish is not really pure Tung oil.
Generally if you get it from a big box/Canadian Tire/if it says minwax on the label, it will be a polymer/urethane type finish that may or may not have ~some~ tung oil in it. Same with linseed oils.
You can get pure tung & linseed oils, just need to shop around for em (Lee Valley / Amazon)
The only reason/benefit I can see to a polymerized finish is that you can get a gloss or semi gloss finish out of them. pure oils will never do that.
My process is:
- colour, either stain, dye or chemical
- sealer if required
- oil, generally 2 or 3 coats of pure tung (I do not like linseed, too long to cure, tung smells nicer anyway)
- depending on end use, maybe a coat of polymerized tung
- depending on end use again, paste wax.
Spar varnish would not have been my choice for a stock.
