Finishing Question

[Bobby O'Neal]

A friend of mine was telling me today of a project he is getting started on, a spring wagon. The question came up about finishing it. He'd talked about putting some poly on it and wondered if it'd be a good idea to seal it before finishing it. Also, any ideas better than poly, considering the outdoor use? All input welcome. Thanks.

Bobby

[Conrad Fiore]

Bobby,
I think this is a where you would want to use the best Spar varnish you can buy. Especially if it will be a working outdoor wagon.

[Bobby O'Neal]

would a spar varnish require a sealer put on first?

[Robert Reece]

FWW did an article not too long ago where they tested outdoor finishes. There was one that did really well, but be prepared it requires like 7 coats.

The other choice is to use white oak which will do pretty well outside by itself. It will gray, but not rot.

[David Thompson 27577]

As another reply has already said, marine spar varnish is a better choice than poly.

Spar is formulated so that it can handle the expansion and contraction that an exterior environment will impose. Most poly's aren't.

As for the sealer, read the instructions on the can of spar varnish. If those recommend a sealer, then use one. If not, then not.

[Scott Holmes]

NOTE: Polyurethane "spar" varnishes and Polyurethane "marine" varnishes should be AVOIDED at all costs.

Poly is highly susceptible to UV damage! Why you ask do they make exterior poly? Cuase it last a year or 2 then you need to strip it and reapply the poly.

(my opinion ---> The marketing guys thinks it's the golden goose; or they don't know any better). Probably the latter.

Go to a boat supply house or a marina to buy your marine varnish there...Look for brands like Pettit, Wolsey, Interlux and Epifanes (probably the best of the bunch). These finishes are not cheap, they will run $40+ per quart and are worth every penny. You will still need to recoat every few years; but they will not break down like poly and HAVE TO BE STRIPPED, all you need is a light scuff sanding and re-coat.


Once the poly breaks down it must be removed... Here in Houston I've seen Marine Poly get chalky/white in less than 6 months! Guy at the restaurant didn't believe me when I told him what to have his painter do to fix it. His painter stripped it and redid it with POLY and GUESS WHAT? six months later it was chalky again! WE don't eat there anymore...

[Conrad Fiore]

As far as I am concerned, the only Spar Varnish is Marine Spar Varnish.

[Steve Schoene]

Given the tendancy of marketers to name pretty ordinary products marine sounding names (eg. Minwax Helmsman Spar Varnish which is one of the least durable) to get true marine spar varnish you need to go to boating supply stores. None is sold in big box stores or regular paint stores. Interlux Schooner, Pettit Captain's, and Epifanes Clear Gloss are the only brands you need consider.

Spar varnish is fairly soft, so to the extent you are thinking about using it on a working surface like a wagon bed, it might not be the best choice. Varnish is for "bright work"--the trim. The functional surfaces are often just made of a outfdoor durable wood like white oak (not red) or ipe or teak and allowed to weather.

You could also use a 2-k polyurethane (100% poly resin not uralkyd in single part finishes) that will weather well. The only one I know that is formulated for roller or brush application is Interlux Perfection. Tough stuff, but if it ever does need repair or refinishing good luck, I think it just laughs at Methylene Chlorine.

[Scott Holmes]

As long as it's not DIY or over-the-counter Polyurethane marine varnish.