HMMWV (Humvee) Pinewood Derby Car

Step 6 Prime and sand (optional)

This step is for that really smooth finish. (You could skip the prime painting and dry sand to 600 grit, but the wood grain will still show through).

Lay light coats of primer down so it doesn't run. The number of coats need depends on your primer. Automotive or regular primer may need 10-20 coats before you sand. Filler primer will need less. Let the last coat dry for 2-4 hour (the longer the better).

Now it's time to wet sand with 320 grit. To do so, dip your wet/dry sand paper or emery clothe in some water and start sanding. The surface you are sanding should be wet, so you may want to dampen it with your fingers. Sand until the surface is smooth. If you sand through the prime, especially on the edges, don't worry. You need to lay down a few more layers of primer. After these layers are dry, wet sand them (this time making sure not to sand through the primer.

Now it is time to pull out the 600 grit and wet sand. When you are done, your car should be silky smooth.

Note:Do not use self etching primer. It will not work on wood. Also, Do not dry sand primer. It's not pretty.