Custom Solar Explorer Build Part 9 Balsa Fin Filling

On the forums, some have asked what Carpenter's Wood Filler looks like when it's dry.
It is "grainy" and shows the brush strokes.

This rough surface is a good guage to tell if the surface is smooth after sanding.

The top fin shows the brushed and dried CWF.
The lower fin shows the surface after sanding with 400 grit on a sanding block.

In my experience, when sanding dried, thinned CWF I don't need anything rougher than 400 grit sandpaper. The CWF doesn't load up the sandpaper. I just hit the block on my jeans pant leg to knock the dust offr the sandpaper.

TIP: I wouldn't sand CWF indoors. it doesn't smell like the old sanding sealer.
You don't want to be breathing it in and it does leave dust everywhere!
There is a warning on the tub: Caution, Eye/Mucous Membrane Irritant. The back panel recommends wearing goggles and a mask!

When you think you are close to the surface, hold the fin up to a bright light.

Enlarge the picture and you can see some shallow brush strokes still on the surface. I'll have to sand a little more.

At the top of the fin you can see the balsa grain just starting to show through.
Don't sand beyond this or you might have to apply another coat of filler!