About 3 years ago I built an outdoor patio table from home depot pressure treated lumber. I walnut stained it and applied 3 layers of Helmsman spar urethane. It looks like the sun/rain has worn down the urethane finish so it's time to re-apply. It even looks like some of the stain is fading. I've never refinished wood like this so I have a few questions, which I think I know the answers for, just looking for anyone with more experience to confirm.
- Is it right to stick with the same spar urethane or should I consider an alternative? (I think the same)
- Should I expect a fresh coat of urethane to give the stain a more even finish, or do I just need to re-stain first? (I think I need to re-stain, I just don't want to)
- How many coats of urethane should I do? Should I expect another 3 coats to last me another 3 years? If I only do 1 coat, will I need to refinish sooner, maybe in 1 year? (I think 3 coats would offer the longest durability)
- How should I prep the surface before refinishing? I've read to lightly sand. If I'm not re-staining, does that mean to hand sand just enough to not remove any stain? Is that even possible? After sanding, I expect the surface will be gritty from what sanding breaks loose. Is it important to thoroughly clean all the grit off before applying the finish? (Was thinking to use one of those fine sponge hand sanders while trying to preserve the stain, and use simple green to clean)
- Is sanding between each coat of urethane really necessary? Does the same apply for cleaning the surface after sanding and before the next coat? (Probably yes)
- If I do re-stain, do I need to sand the surface down to bare wood? (Probably yes)