Some 220 grit was wrapped around a BT-20, a smaller tube than the BT-50 tube supplied in the kit.
TIP: Sometimes you can get a better rounded root edge by sanding the underside curve on a smaller tube.
On the right the upper picture shows the fit of the 3/16" tunnel before sanding the curve into the bottom.
The inset picture shows the fit after the contour sanding.
The bottom sanding isn't really needed on the shorter 1/8" tunnels.
Dear Sir,
ReplyDeleteThank you very much for the blog. I have really learned a lot by following it. I have a question also; how do you prevent sanding a 'flat spot' on balsa nose/tail cones when sanding the CWF? When I use a sanding block, I somehow seem to create a lot of thin, flat, longitudinal 'stripes' on a nose cone; instead of a smooth cylinder. The use of foam sanding pads help somewhat, but I sense my method must be somehow flawed. Any tips you could give me would be most appreciated. Thank you very much for your time and expertise.
Sincerely,
Mark Wilkerson
Hi Anonymous,
ReplyDeleteI wouldn't use a sanding block on round surfaces like a nose cone or a rounded leading edge of fins.
Take a small piece of 400 grit over your finger for those. Your fingertips will give you a rounded, cushioned backing for the sandpaper.
Sanding pads may help but usually aren't made in the finer grits.
If the pink balsa peeks through the CWF, you have probably sanded through it. If you can you want to leave a very thin "biege skin" on all the CWF surfaces.
Don't ever wet-sand the CWF. It is water based and doesn't seal the filled balsa or body tube seams. Only wet sand after your primer coats.