Mr. Surfacer Drying time before sanding

Depends on how thick it is. I don't sand it much myself but when I do, about an hour. I normally use a cotton swab soaked in Mr Color thinner 110 and rub the surfacer until I get the "fill" I want and it feathers nicely.

I've sanded it much sooner but sometimes it starts to roll up or fills the sanding stick very quickly, indicating it's still not dry enough.

I've gotten to where I use a Q-tip and isopropyl alchohol to "sand" it after 10-15 minutes. In many cases, that is all that is needed. If it needs more sanding after that, I give it an hour to avoid that "roll-up" hks mentioned.

I've always meant to try making a little puddle of it, letting it dry, and see if it could be applied to bigger gaps almost like putty..... I awlays for get to do it when I run into a time when I need it.