spar varnish, tung oil & beeswax

[Jay]

A few moons back I'd heard that Sam Maloof of furniture fame used equal parts spar varnish, tung oil and beeswax as a rubbed on finish. Heated till the wax melted and everything was well combined. I tried it on a simple desk at the time and was pleased with the result.

Any thoughts on how this would work as an exterior brightwork finish? I'll do a test on a spare bit of teak and leave it out to weather for a while, but was wondering if anyone else has tried it?

Jay

[Pekka Huhta]

I have used plenty of tung oil spar varnish and different finishes containing beeswax. Not mixed them together before the application, though.

The closest I've come to that was boiled linseed oil, Stockholm tar and beeswax. Makes a wonderful finish for my lapstrake scale models and smells good. Just tar and linseed oil is the usual finish for a real traditional small lapstrake boat around here. Beeswax just 'breaks the surface'. Tar and oil together creates a hard surface, beeswax softens it a lot. For the scale models the surface looks more real, "to scale". Silky.

When building furniture I have put on one or two coats of eggshell varnish and waxed a silky finish on with beeswax or used just beeswax spiced up with some boiled linseed oil and turpentine. Gives a beautiful gloss.

What I know of beeswax is that it's a great interior finish and can be mixed well with a variety of other finishes, but I wouldn't use it mixed with varnish. At least on any exterior finish.

It might be used where you normally would use just oil, which would leave it to the interior finishes.

Pekka

[thechemist]

Tung oil will self-cure because it has so many conjugated double-bonds. They oxidize very readily.

Sadly, hardly half of them react, and it is unreacted double-bonds that cause rapid varnish breakdown on UV exposure. Those same left-over double-bonds also absorb some of the ultraviolet.....until they break down.

That formula, while inexpensive to make, will fail rapidly and should only be used on boats that are not exopsed a lot to the sun.

It contains neither antioxidants nor ultraviolet absorbers aside from its own resin system, and thus offers fair wood protection for a very short time and then a rapid breakdown and rapid loss of wood color.

In Finland, the ultraviolet exposure is much less since the sunlight is filtered through a much greater thickness of atmosphere than in locations closer to the equator of the planet.