30 minutes Click to see full answer. Similarly one may ask, how long does car putty take to dry?If your filler hardens too fast, you used too much, if it takes too long, you didn’t use enough. You only want to mix what you can use in about 10 minutes. Properly mixed, body filler will begin to thicken in 10-15 minutes, and be fully cured in 30.Also, how do you use spot putty? Directions for Bondo Glazing & Spot Putty Sand the surface of the damaged area with 600-grit sandpaper. Squeeze a two inch long line of Bondo Glazing & Spot Putty onto the thin blade of a plastic putty applicator. Allow the putty to cure for 30 minutes or until hard to the touch. Blend the putty into the damaged area by sanding it with 200-grit sandpaper. Additionally, does spot putty need hardener? Spot putty is another type of filler that is used to fill tiny pinholes in the body filler. If you don’t fill those pinholes, the filler might crack when there is any movement of the underlying metal. It is very easy to sand, dries fast and doesn’t need a hardener to cure. You can just apply it from the tube.What is glazing and spot putty?Bondo Glazing & Spot Putty is a 1-part putty that fills imperfections, pinholes in body filler, scratches, paint chips and minor dings. Can be used with other auto body repair materials.