On Jun 5, 8:18*am, (Mike Hennessey) wrote:
I want to try using a sponge to smooth the drywall
joints instead of sanding in an effort to reduce
the dust generated.

How long should you let the compound dry before
using the damp sponge?

A poor technique at best.
Use a good shop vac in conjunction with a MagnaSand unit. The outfit
comes with a screen type sanding pad that is sucke flat to the wall
and makes sanding way easy. The dust is trapped in the MagnaSand water
bucket for easy disposal. Some folks with clay type soil put the wet
dust on their garden since calcium sulfate (gypsum) is a known clay
soil conditioner. Use a spritz of Pam cooking spray to control foaming
in the water trap. HTH

Joe