After I put in a new pressure treated 4x4 fence post (set in cement), it developed a 2-3 inch crack/split at a corner near the middle, probably due to exposure to rain/sun. I don't think this affects the post structurally, but I would like to fix it for cosmetic reason and to prevent it from splitting further.
I would like to put some glue into crack, clamp down and let it cure. What is the best glue for this purpose? It would have to be weatherproof (water and UV rays proof), and fill small voids. Slightly flexible would be nice too.