I just discovered this Sika Fence Post Mix, which is a two-component, pre-proportioned polyurethane resin for anchoring 4x4 pressure-treated fence posts. Does anyone have experience with it? It says one bag will expand to fill a 3-foot deep, 8-inch in diameter hole for a 4x4 post. I can't find any info for use with 6x6 posts, or whether it's even recommended for 6x6s.
Some downsides --
1) you have to store it within a narrow temperature range prior to using or it will either start to expand too quickly (sooner than the 30 second time) or not quickly enough and compromise its integrity.
2) if you spill any outside the hole, you'll run short on foam for the post.
1) Much lighter to haul around when purchasing vs. 50# bag of instant cement.
2) Any excess set foam can just be sawed or cut off with a knife.
3) Lower mess, no cleanup. Just throw the bags away.
4) Easier to remove posts down the line if you need to.
5) Supposedly as effective as cement in anchoring the post.