finish for walnut for exterior use

[patrick anderson]

I make "modern" birdhouses and feeders as a bit of a sideline gig.

The first feeder I made was a combination of pine and birch ply. I used a dark stain on it from sherwin and it turned out ok but a distinct lack of grain.

I'm going to make the future ones out of walnut and walnut ply. I'm looking for suggestions for finishing the wood. I'm not sure whether to use oil or a wipe on poly or anything else. The main thing is I want the wood to be as dark as possible while still showing the grain. The other thing is that these obviously are outside and exposed to the weather. I need a solution that wont require maintenance every 3 months or so by the buyer.

Any suggestions, tips and ideas would be most appreciated.

[John Dow]

Hi Patrick,

I know this isn't what you want to hear, but I don't think there is any finish that will do what you want. Ultra-violet light really beats up wood and finishes, and the dark coloring in walnut fades very quickly. About the best option is a high quality marine spar varnish, with lots of UV inhibitors, not the stuff from the local borg. A true paint store (like Dunn Edwards) should be able to guide you a bit better - Even the one I go to in Albuquerque carries a Sikkens marine varnish (lots of boats out here in the desert).

However, I'm not really optimistic on the subject. I've never seen exposed walnut keep its color very long. In my area (6800 feet elevation, lots of UV), unfinished walnut starts to fade in just a few days. Even with the best available finish, I'd be surprised if the color remained unchanged for even a few months.

Best advice I can offer is to do some finish and species testing to see which woods behave best under the conditions you expect. You might find that I'm full of it and walnut/spar behaves well enough for your needs . Or you might find that you have to go with teak or something. Ipe's a good one too, I'd say maybe the best for your purposes, but man will it ever wear out your tooling!

Hope this helps, don't let my attitudes discourage you - in other words, experiment!

And post some pictures of your work if you can (we love pictures).

[patrick anderson]

John,

Thanks for the input. I've considered teak but the colour isnt quite what I wanted as well as it being $$.

Here's a couple of images



I've considered going with a marine varnish and will look into that further. Maybe some others here can toss in their 2cents worth.

[John Dow]

Hey Patrick, however you end up doing it, those are some nice looking birdhouses!

I like the second one especially, keep it up!

(added) - I was just reading Jay's new post, check out the link in it, about using marine epoxy with varnish on top. Epoxy isn't terribly UV stable, but the varnish might take care of that. Worth a test anyhow.

[patrick anderson]

anyone else got any ideas?

[Jeff Horton]

Spar varnish is the only choice. I have owned and been around boats a lot. Mahogany runabouts, sailboats, etc are always paint and spar varnish. Nothing else will hold up to the sun. And as you were told Walnut is not a good outdoor wood.

[Chris Barton]

1) Consider a wood better suited to the outdoors such as cyprus or cedar

2) Use a marine varnish or poly with UV protection only if you want to be refinishing in a couple of years. Otherwise, don't finish the wood. You can still color the wood with stains to achieve the tone you want but, any stain and varnish combo will degrade within 3 years if exposed to the sun.

3) Avoid the use of plywood. It will delaminate over time.

4) Consider painting your birdhouses. Paints are much better for UV penetration, that's why most houses are painted.

[patrick anderson]

Thanks for the input from everyone.

I think the paint idea is probably the best bet although it wont look as good as first envisioned.

I think I'll need to think this over some more.

Thanks again for the input.