On Sunday, 19 July 2020 22:14:03 UTC+1, DStocker wrote:
replying to jon.p.weaver, DStocker wrote:

I have been successful in removing 6 of my 8 posts down to the cement "bottom"
(22"), that were rotted out at the top of the cement but your right, it can be
a difficult process. Each post had a different level of rot and difficulty.
Even then, the new posts were bigger and required plaining to fit the holes.
We live in an area where fence contractors just cut the old posts off and dig
new holes for the new posts because of the rock tailings from the gold rush.
They leave the old crete in the ground. It seems the moisture trapped in the
post, as well as the depth of the post in the create keeps it from burning,
smoldering, like a tree stump would do after being prepared for burning. But
that can take 6 months or more. The depth seems to deprive the burn of
oxygen. Charcoal worked well up to about 8 inches. Then, I used a 5/8 drill
bit with a 22" shank available at HF. I drilled many holes down as far as they
would go and smashed them together with a 6' x 1" carbon steel pry-bar. Then
a cheezy planting auger that has about about a 2.5-3" width that I sharpened
in the grinder. I pulled the pieces out with a vacuum. I'm thinking, if I
had an acetylene torch, I could turn the oxygen on low enough to just feed the
smoldering process?

crazy expensive though. You don't need acetylene for wood.

? Or just it to burn the post out like a small kiln. Maybe
a small fan from a computer on the top of the hole to keep the air
circulating? There has to be a better way to do this.