Best finish for wood that will be outside in the elements?

[Mike Manning]

Last year, I picked up two aluminum adjustable-height stools that needed new seats. This week I finished them, making the seats with SYP. They've currently got 3 coats of BLO. My plan had been to maybe keep them around the shop even though space is critical. Well, the wife saw them and liked 'em. She wants me to put them on the deck out back. So I'm wondering what would be the best finish to put hopefully on top of the BLO to have them last in the sun and rain and sun. We get lots of sun in Central Texas. :0) Thanks!

[John TenEyck]

A cover. Seriously, the best protection is to keep them covered except when you want to use them.

John

[Rob Luter]

Creosote. It will shed weather like gangbusters. Great for pine telephone poles. Not butt or clothing friendly though. As John suggested, cover them. SYP isn't great outside. Make sure the end grain is sealed up well. As an alternative, make a set of seats from White Oak or Ipe. Both do well outside.

[Mike Manning]

John,
I hear you. I've tried many times before to get my wife to put her gardening tools away but she leaves them wherever she used them last. So many have been ruined by the elements and half the time she can't remember where she left a tool the next time she wants to use it. The reality is the stools will be left to the elements so the best I can do is try to protect the wood. Luckily the legs are aluminum so I don't expect those to corrode.

So...still looking for advice on best finish for these. Hopefully something I can put on top of the BLO finish.

Thanks!
Mike

[Rob Luter]

You might consider marine grade varnish. I’ve seen some folks use clear epoxy as a durable finish too. Outside the box. Way outside the box.

[Andrew Seemann]

If it wasn't for the linseed oil, I'd say paint.

[Mike Manning]

How often would they need to be touched up if I use the marine grade varnish?

[John TenEyck]

How often would they need to be touched up if I use the marine grade varnish?

Every year. No kidding. If you want to go the marine varnish route I think you should first wipe off as much of the BLO as you can using Naptha or mineral spirits so the bonding will be as high as possible.

And use something good, like Epifanes. Helmsman and others you can buy at the BORG won't survive a year.

John

[roger wiegand]

Exterior stain. We maintained about 100 picnic tables for a family business. They were repainted annually for decades and always blistered and peeled because of the moisture on horizontal surfaces. Going over to a stain eliminated that problem and the invention of pressure treated lumber slowed down the rot. With any film-forming finish the water will eventually get underneath it and lift the finish; with pine especially in the sun and rain small cracks will continually open and close allowing water penetration. The stain allowed the water to evaporate from the surface so the tops and seats stayed decent looking throughout a season and allowed recoating without the nasty scraping/priming routine that had become part of the spring ritual.

[Edwin Santos]

Every year. No kidding. If you want to go the marine varnish route I think you should first wipe off as much of the BLO as you can using Naptha or mineral spirits so the bonding will be as high as possible.

I wish I could disagree with John, but unfortunately what he is saying has been my experience too. Even with high quality marine varnish (I have tried both Epifanes and Waterlox).
Certain things can affect your longevity such as the amount of sun exposure and how many coats of varnish you apply, and how much material. They say the gloss product will last longer because the reflectivity is part of the resistance to UV light, but even then, the maintenance demands will be pretty high.

One day maybe we woodworkers will have available a clear wood finishing product that can stand up to Mother Nature, but that day is not here yet as far as I know.

[Mike Manning]

Ok. Thanks guys. I am probably going to want to go with a different wood selection per Rob's suggestion.

[Andrew Seemann]

White oak is your friend