Bullet Proof Finish for Outside Cedar

[Jason Morgan]

Making another set of Norms chairs and would like a truly bullet proof finish (something that will last more than a few years).

I was thinking Helsman Spar Varnish, but didnt know what else was out there.

Thanks!

[Todd Burch]

It's my opinion that that finish has not been invented yet.

[Bruce Page]

It's my opinion that that finish has not been invented yet.

I agree. I think the best you can do is a spar type finish.

[Jason Morgan]

I was afraid of that.

Thanks

[Dewey Torres]

Jason,
This topic has been brought up many times before and I will try to restate it:

Cedar and along with a few other outdoor friendly woods will last for a very long time out doors with no finish. Putting a good marine finish on them will most likely make them last so long that by the time they deteriorate you will be happy that you get to build another to improve the design or try something new.

Don't be "afraid" that there is no finish that is bullet proof.

[Brian W Evans]

The current issue of FWW (#205) has an article on exactly this topic. The best performers were a marine varnish with extra UV blockers (7 coats) and the same varnish (5 coats) on top of an epoxy sealer (3 coats).

The marine varnish they used was $45/quart, but the samples they showed after a year's worth of weathering looked pretty darn good.

[Mark Versprille]

My exterior clear finish is pretty simple. first coat is 1/3 Helmsman, 1/3 boiled linseed oil, 1/3 mineral spirits. I lay it on very heavily. Heck I flood the surface and all joints. I let it soak for 15-20 min and wipe off excess. There is less excess than you might expect. Because it's so thin it really gets soaked up. Let it dry for at least 24 - 48 hrs.

scuff any rough areas smooth.
second coat is two parts Helmsman to one part mineral spirits. I only put on enough to make a thin film. Let dry for at least 12 hrs.

scuff all over with steel wool.

Three more coats of undiluted Helmsman scuffing in between each and allowing 12 hrs drying between each coat.

I won't call it bullet proof. On a poplar mail box, full sun and weather exposure every other year I scuff with steel wool and wipe on a thinned coat of helmsman or boiled linseed oil and it looks brand new.

[Cliff Rohrabacher]

Any of the two component catalyzing urethanes will be slicker 'n cat §#¿$Җ on the door step.
Epoxy systems is where I get mine.

http://www.epoxysystems.com/coatings.aspx#Polyurethane_
They even got water based which I am keen on trying.
http://www.epoxysystems.com/coatings.aspx#Water_Based

I would call and speak to their really helpful tech guy.

[george wilson]

The best spar varnishes FWW tested BY FAR were the Epifanes. There is a regular type,and a 2 part epoxy type. They both did about equally well. The other varnishes showed grey here and there on the samples which were exposed to 3 years in widely varying states. Google the name. Jamestown Distributors in Rhode Island sells it. There are several types of the brand,be sure you get the outdoor marine type.

[Cody Colston]

I'll second that recommendation to use Epifanes varnish. Put on the seven coats FWW recommended and it will hold up for a year or two. When it starts looking chalky, sand it with P150 and re-coat. If you let it go too long, it will begin peeling and is then toast.

[Howard Acheson]

Minwax Helmsman Spar Poly was the first clear finish to fail in Consumer Reports tests of outdoor finishes. Polyurethane is rapidly attacked by UV from sunlight. UV additives do little to slow up the process. In fact, Minwax make another product called Clear Shield the contains even more UV inhibitor additives but it too, fails within a year.

As has already been said, the best exterior clear finish is Epifanes Clear Varnish. It's not cheap and the directions call for seven coats I believe. Even then, the finish must be sanded each year and a couple of more coats applied.

The rule of thumb for outdoor finishes is the more opaque the finish, the longer it will last. Clear finishes last only a short period.