Replies

1. 
   john_c2 | Feb 21, 2021 09:23am | #1

   Osmo is not going to hold up outside, at all. For a clear finish the only choice is a marine grade finish with the highest uv protection. Or paint.

2. 
   stantheman | Feb 21, 2021 10:39am | #2

   I've used Cabot Australian Timber Oil, and Penofin products for outdoors - in other words finishes that people use on decks and fences, not indoor furniture. But the bottom line is that nothing lasts for long outside, even spar varnish, and you have to reapply regularly to keep a finish on, or let it all go naturally gray.

3. 
   gulfstar | Feb 21, 2021 11:17am | #3

   Spar varnish will go very well on this type of wood. I have used it abundantly on mahogany and teak on boats. Mahogany will get a gel stain first so it stays red and uniform under sunlight and a minimum of 6 coats applied as thick as possible without runs (except the first one which is thinned) . Marine Cetol will also last but it has a orange tint that doesn’t please everyone and is fragile to impact and wear.

4. 
   user-7022764 | Feb 21, 2021 07:49pm | #4

   I have used the cabot timber oil on some Alaska yellow cedar that is outside here in the PNW and its doing quite well compared to other varnish finished I have on other yellow cedar pieces from last spring.

   I am going to use more of that this spring on other projects.

5. 
   user-6851987 | Feb 21, 2021 08:12pm | #5

   Thank you everybody for ideas/recommendations

6. 
   matsol | Feb 21, 2021 08:54pm | #6

   Waterlox is fairly hearty.

1. 
   matsol | Feb 21, 2021 08:55pm | #7

   *hardy

7. 
   lat_axe | Feb 22, 2021 04:21am | #8

   I'd avoid varnishes as they're much harder to re-apply when they eventually fail, as they and all outdoor coats eventually do. Varnish flakes and the parts that are still stuck can't really be left if you want to re-varnish as they show like scabs. It takes an age to sand it all back to bare wood.

   Varnish will last longer than oil - maybe 2-3 years at most in the Welsh climate.

   Personally I use an oil-based stuff containing a mild fungicide and some stain to match the natural colour of the wood. I expect to re-apply it at least once a year and usually twice a year.

   Oil finishes can be put on top of the remnant of the previous finish after a rapid sand of the surface with an RO sander to take down any raised grain and to give a key to the finish you're about to apply. No scabs.

   You do eventually build a slightly thicker coat of the included resins of such an oil finish so that it lasts a bit longer each time. You can often go from twice a year to once a year after 2-3 years of the 6-monthly reapplications.

   The main functions of such a coating are: to stop the underlying wood checking, mildewing & greying; to keep the wood underneath looking like wood rather than having it painted over. (You can see the grain and keep the wood colour). If the wood itself isn't durable (resistant to beetle and fungus) it'll eventually rot outdoors anyway, finished or not.

   Well, it will in the Welsh weather. :-)

   Lataxe

8. 
   kudzupatch | Feb 22, 2021 08:47am | #9

   Two 'secrets' to Spar Varnish.

   1. You get what you pay for. Better grade/expensive Spar Varnish has more UV protection and will last much longer than the cheap stuff at the Big Box Stores.

   2. Recoat regular, BEFORE it fails. Then you just need to scuff it up and reapply. If you don't you have just about have to strip and start over.

9. 
   gulfstar | Feb 22, 2021 02:41pm | #10

   12 years + with a few touch-ups. Good varnish, good preparation and a lot of abuse.

   
10. 
    fivebirdscustom | Feb 22, 2021 08:25pm | #11

    I am refinishing a set of mahogany doors that will sit outside in the desert sun. I did a bit of research before starting and was turned onto System Three Clear Coat epoxy sealer, then Epiphanes polyurethane.

    I've done boat work before and used some Spar varnish, but was not convinced that it would last very long.... But, I've read nothing but good things about Epiphanes. I am hoping the epoxy sealer coat helps as well (like it was reported to do)....

11. 
    ct_engineer | Feb 22, 2021 11:39pm | #12

    Design and process also helps. Finishes thin out when applied to square corners and that's where they fail first. Take some time to round corners and edges on outdoor projects - it doesn't need to be a big radius. Think about refinishing frequently when you design a project, make it easy to sand and recoat where you can.

    It is also critical to seal end grain, especially if it will be in contact with the ground. Consider giving the base of wood feet an epoxy shoe that is part of the design and keeps pores from wicking moisture leading to swelling.