On Tue, 15 Nov 2011 20:14:14 -0500, blueman wrote:

Can I get an intermediate setting time by mixing say 20-minute and
90-minute setting joint compound?
i.e. will I get a uniform intermediate setting time (assuming I mix it
well) or will some set fast and other set slower.

(Note: I know that with West Systems epoxy you can mix different
hardeners to get intermediate curing times but not sure if this works
for joint compound).

Thanks
Apparently it works - but the hardening time is not linear with the
mix - and you need to mix it well DRY before adding water. Don't try
to "batch mix" it on the fly.