Pressure Treated Post question

[oakey]

I have been reading around and couldn't come up with an answer about this...

For pressure treated post that will be set in the ground, which is the number of water retention to look for .40 or .60?

Which is better?

[Don_P]

.60 PCF, pounds per cubic foot, of ACQ, alkaline copper quat. This is the minimum retention level for foundation work. If you can find foundation grade it is selected for no heartwood. Heartwood does not accept the treatment chemical so foundation grade is treated deeper. Just as an aside never buy
"treated to refusal", this is usually peeler cores from plywood manufacture and is all heart, since heart accepts no significant amount they simply are saying "we tried". I've used a small amount of "micronized" ACQ treated that carries much lower retentions, is barely green, and according to the supplier is just as good as higher retentions of conventional ACQ but is less corrosive to fasteners... I've got my doubts. With all of this use hot dipped galvy hangers and fasteners, Zmax, $tainless, or fasteners specifically rated for ACQ. Don't mix stainless and galvanized. When we switched from CCA to ACQ the copper was increased and the chromium was dropped, this results in far higher galvanic potential. With plain steel and wet wood I've heard you have a half volt battery going. Also avoid aluminum around treated.