The putty dries pretty well within a half hour or so........but I'll take my time and let it sit overnight. The only problem with this putty (as with any putty) is the terrific dust it leaves behind! I'll have a bowl of water nearby to try to keep the dust down by keeping the sandpaper wet. Later, I may round off the corners somewhat on the tulip panel as to my view, the rear window corners seem a bit "square".