# Polyurethane for logs - Outdoors



## ColoChris (Feb 12, 2010)

Hi to all,

I am working with some pine logs that are dry

These logs will be for outdoors like furniture and outdoor decorations

What I am curious is if I can use a polyurethane over the logs to prevent rot or anything that may happen?

Being in Colorado myself, we have snow, hot, and wet seasons. 

But I want something that will make a hard shell and not let anything in, but I worry that it wont let anything like air out causing the logs to rot or become unstable.

Any help or thoughts are greatly appreciated.

I am looking to take some larger logs say 14 inches to make a rustic porch, but again being weight bearing I want to make sure the logs will not rot, so I though a polyurethane would be good.

I know I sound like a broken record, so any thoughts would be great.

Thank you in advance

Chris


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## Steve Neul (Sep 2, 2011)

You would have to make sure the polyurethane was an exterior grade but could be used. I think you would be better off with a marine grade spar varnish.


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## Fred Hargis (Apr 28, 2012)

I would suggest untinted paint. This would be the #4 (Olympic) or #5 oil base, and just brush it on. It looks very miuch like varnish once dry, though it may be a little cloudy in the can. Buying it can be a bit of a struggle....Skippy Stockgirl at Lowes didn't want to sell it to me untinted: "we can't do that" (!). Anyway, if you want to read a little more about this take a look here. Otherwise I'd go with a good grade of marine varnish from a marine supply. The paint will likely be a lot cheaper and work very well....it's became my outdoor finish of choice once I learned of it.


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## ColoChris (Feb 12, 2010)

Hi and thank you

I may have an issue...

I tried some poly last year on a few logs and noticed a few days ago it was flooring poly and interior version.

Am I in trouble? I know it has no uv protection, but does the uv just keep the wood from turning yellow?

I mainly worry about structurally if the sun can make the logs brittle and break?

I guess I need to fix it first, but for my new projects take your suggestions


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## JohnnyTooBad (Dec 9, 2012)

I agree with the marine spar varnish. It has UV protection and is meant to allow the wood to breath and expand/contract with temp fluctuations, as well as constantly be wet. That's why they use it on boats. But don't make that lead you to believe that it won't need maintenance. My father has been using poly marine spar varnishes on his boats for many decades. Granted, he's using a lot of gloss and semi gloss and trying to maintain a perfect finish to make his sailing buddies ohh and ahh over his teak, but he's sanding and recoating every 2-3 years, and he covers almost every inch of exterior teak when the boat isn't in use. Also, because it is more flexible and breathable, it's not a super hard finish like floor finishes. But floor finishes are also brittle and probably will peel, crack and chip if used on exterior wood.

Being logs, I'd also recommend spraying. It's easier and will get in any cracks, pits, etc. 

I'm not positive, but there may also be spar varnishes that have some sort of pesticide in them to keep bugs out of your wood.

I'd recommend looking at WestMarine.com. high quality stuff.


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