I'm building some outdoor furniture. The butt joints are held by SS screws,so they won't rely on the glue much for strength.
I would like the glue to serve as a coating/caulking between the butt joints. The water trapped between a tight butt joint is where I see it rotting the wood. The joints are Redwood battens screwed to the under side of Redwood table tops. Yes, Redwood is rot resistant but some of this has sapwood. The sapwood is only a little more rot resistant than Doug Fir. I've seen many 20 year old Doug Fir picnic tables around here still going strong, so this is probably overkill.
I'm considering Titebond III or a waterproof construction adhesive.
Has anyone tested Titebond III for many years of soaking /drying?
My gut tells me construction adhesive might be best for something like this.