Gotta love TALENT!Jack, there are many types of wood for outdoor projects: personally, I use redwood or cypress. larger signs, such as the National Parks, I used HDO plywood (High Density Overlay) which is rare for the average consumer. MDO (Medium Density Overlay) is more common in the box stores.
if you are looking for one product (wood or paint) to last 20 years without maintenance, it's not going to happen. anything outdoors needs to be taken care of and maintained according to that project and weather conditions.
with proper eye and respirator protection, you could use pressure treated wood from Home Depot called YellaWood.
but, it too needs the appropriate priming and painting regimen. I have seen many "trail signs" that were routed only with no paint at all and allowed to weather naturally. (much easier to replace if needed).
sorry to ramble on, but, I've been making wood signs for outdoor use for over 40 years on a commercial basis.
this is totally your call as to where the trail signs go and how long do you want them to last. we're anxious to follow your projects all the way through to the final installation.
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