Estes AMRAAM AIM-120 Downscale, Build, Part 7, Fin Grain Filling & Reuse Sandpaper TIP

STEP 1

On the left, a lower fin with a brushed on coat of thinned CWF.

On the right, another fin after sanding smooth with 400 grit. 90% of the grain is now filled.

STEP 2

Here's the front and rear fins after sanding down the Duplicolor  filler/primer that followed the CWF. The grain is 100% filled.

Balsa grain filling can be a simple two-step process. After spraying with color coats there shouldn't be any visible grain.

Saving Money!

TIPS: You don't have to throw away sandpaper when if gets loaded up with filler/primer.

Buy a soft brass brush, I got mine from Home Depot.

Brush off the gunk with the brush under running water. Use a circular brushing motion. 

Here's the same three pieces of 400 grit, 

ready to go again!

I wouldn't recommend wet sanding on balsa and Kraft body tubes. Both will absorb water and swell up.