Darryl wrote:
I'm in the final stages of finishing the bathroom and am about to lay
some plywood and 1/4" backerboard with thinset under each layer. I'll
mix the thinset in a 5 Ga pail, using...a hammer drill with the
appropriate bit/paddle?

TIA!
Darryl

Get one of these; http://www.tiletool.net/wpe39.gif
Use it with a variable speed or low rpm drill.

Why are you putting thinset underneath the plywood?

I'm not and I've proven once more that I should not post before my
morning coffee (umm...the plywood is already down...lol). The thinset
is going under the backerboard and tiles only.

Thanks for everyone's replies (I picked up that exact tool at HD)
Darryl.