# Exterior Finish Question



## HebronLLC (Oct 11, 2009)

I have recently been asked to give a bid on refinishing a couple of exterior doors for a small local historical museum. I have limited knowledge of what external finishes work the best and would like some advise. Water is not much of an issue since we are located in central New Mexico, but sun exposure is another matter. The doors receive 8+ hours of direct (and often harsh) sunlight each day. Now my plan was to use a marine grade poly, Minwax Helmsman to be exact, but I have heard that it doesn't hold up to UV very well. My question is; what *brand* of finish works best (in your honest opinion) in harsh UV conditions. The museum of course does not want the hassle of putting a coat of finish on every 3 months either, so it will need to be something that preferably last for a little while. I have already advised them that they will need to put at least one coat of finish on a year no matter what I use, but the longer that period of time is the better in their opinion.

Thank you for any advise you can give.

Aaron


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## jayjay (Jan 22, 2010)

Araron, I built a few southwest style gates out of pine for my back yard about 5 years ago. I applied Helsman Spar Urethane to the wood. And the sun just ate it up. .I have to sand and recoat at least once a year, otherwise it just starts to crack and peel. It would work great if it wasn't exposed to the sun all day, but the hot sun just tears wood up. I'd be interested to hear what other have to say too. Sorry I couldn't be of more help.


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## a1Jim (Aug 9, 2008)

Spar varnish


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## bobkberg (Dec 26, 2009)

I'm going to what looks like a complete digression, but I'm absolutely serious about this.

Some years ago, I had varnished up the oak threshold for some outside doors, and not gotten them installed, so they sat in the shop for several months. Eventually, I did get them installed - and sanded and re-varnished the oak door sills right next to them.

Fast-forward a year or so - I noticed that the thresholds still looked good, and that the sills looked terrible - weathered.

Some years later, I happened to be talking to a paint chemist and mentioned this to him. He told me that for roughly 6 weeks, most varnishes are still curing (even though already dry), and that by keeping them away from ulltraviolet light, the lifespan of the finish could be extended dramatically.

I refinished my front door a few years ago, and kept that in mind. I kept the door in the shop for a couple of months
and then remounted it. it's now 3 or 4 years since then, and the door still looks brand new.

To echo Jim above, spar varnish is formulated to resist ultraviolet (among other things), but if you can keep a temporary (cheap) door in place and let the varnish cure, I believe that you'll have a far longer lasting finish.


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## Chilly (Jan 8, 2010)

Jim's right.

As far as brands go, though, all are definitely not created equal. Pratt and Lambert's spar varnish worked fantastic for some glulams I built for my shop roof. The front sections are fully exposed and have been for 2+ years here on the prairies. There isn't a hint of cracking/deterioration at this point. Two coats are on right now. It'll need a recoat this year just to stay ahead of things.

You can tell by the depth of colour as well, how effective it may be. The Minwax Helmsman (not so great) looks like water compared to the P & L which looks more like maple syrup. That's why straight clears are usually worse for UV simply because so much light can pass through.

You may have some luck with an automotive clear. Even though the UV will still pound the wood underneath some of the finishes are very tough and can flex pretty good so they resist cracking, but 
you'd need to talk to a paint shop pro about that one.

to bobkberg…good advice, thanks for that.


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## miles125 (Jun 8, 2007)

I cringe when i see a nice door without adequate overhang protection from the elements. You may as well be planning on what kind of finish would a roll top desk need if you planned to sit it in the yard.

The downside to most spar varnish finishes i see on doors is that they look too plasticky…(Is that a word)? I'd definitely go with a satin if possible.


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## hObOmOnk (Feb 6, 2007)

Miniwax is to woodworking what Twinkies are to fine French pastries.

For good UV protection, try one of these brands:

Epifanes - the gold standard for real spar varnish.
Sikkens Cetol - great UV protection.
Waterlox Marine Finish - tung oil based.

Expect the need to refresh the finish every couple of years.

Jamestown Distributors is a good source for marine products.

I speak from experience not internet hearsay.


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## Chilly (Jan 8, 2010)

[email protected] Sikkens is indeed good stuff, good dr.


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## kerflesss (Mar 7, 2009)

Aaron,
You might check out WoodWhisper and watch this video on finishing his mom's door in the desert of Arizona. He's partial to Epifanes. Good luck…

http://thewoodwhisperer.com/episode-46-desert-outdoor-finish/


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## TopamaxSurvivor (May 2, 2008)

What ever you use, check the UV ratings on it. The good stuff will be very expensive.


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## TopamaxSurvivor (May 2, 2008)

Check this out; http://www.penofin.com/products_logon.shtml


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## toddc (Mar 6, 2007)

Sikkens Sikkens Sikkens


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## HebronLLC (Oct 11, 2009)

Thanks to all who responded. I am now weighing my options and will let you all know what I choose and how it turns out. Of course if anyone has any more bright ideas I am more then willing to hear them.

Thanks again.

Aaron


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