Matt and I applied the micro fairly early in the morning. By evening it was dry enough to sand. Being in the mid-80's helps speed up the curing process.It didn't take nearly as much effort to sand the micro as it did the flox the other day. I love this stuff! I can't believe how incredibly smooth the end result is. I think I am going to really like working with fiberglass after all. You can't get aluminum this smooth, that's for sure!