In general we feel that the long term durability of a wood bed is mostly dependent on the finish applied, not so much on the wood species. Of course you have to start with good wood, proper drying, selection, and machining. Years ago we searched for some comparative tests which would help us recommend finishes, but found none we were comfortable with. Hence the tests we conducted at that time. The most durable is the use of POR15 under exterior paint, which was somewhat accidental. We just had POR 15 on hand and decided to try it. The last test samples have been outdoors 24/7 for 12 years and still look good. Its a test environment and no guarantees yours will last 12 years, but it is the finish I used in my personal truck bed and what our testing indicates to be a durable finish. If anyone has data indicating a better finish, we would love to know about it to pass along to our customers.
We tried a sample with the West epoxy, it did not last very well. That product is generally highly recommended so I suspect the problem was with our technique. We did not do further testing with the epoxy but the idea of totally sealing off the wood to prevent moisture is correct. However epoxy is not generally UV resistant and needs additional protection to prevent damage from the sun. Be mindful of the critical narrow time window for applying following coats over the epoxy as well as over the POR15.
Mar-Ketch
