Filling Body Tube Seams TIPS

For filling body tube seams, I was mixing the CWF a little thicker than what was used for balsa grain filling. The thicker filling didn't seem to chip out of the seams when sanding to surface.

I had two separate containers of CWF, one thinner for balsa and a second a little thicker for body tube seams.
In the container (with the thinner CWF for fins) I noticed the filler at the top of the tub. This is what was left when I would wipe off the excess off a brush. This filler was slightly dried and a little thicker than the filler in the bottom of the jar.

This drying filler turned out to be just right for the body tube seam filling, a bit thicker than the brushable balsa filler.
I dipped just the tip of my knife into the thicker CWF at the top.

Set the blade into the seam and drag the CWF drop down the trough.
The blade helps guide the CWF right into the seam.
You can only do about an inch at a time, then remove the excess.

A razor blade is lightly dragged over the CWF while it is still wet.
Don't press hard on the CWF, you want to leave a "skin" of filler over the seam. Don't press hard or you'll pull filler out of the seam.
This will be sanded down to surface after drying with 400 grit.

TIP: It's easy to see the seams on the white tubes. On the brown tubes sometimes you can't see them.

Use a sharp pencil and draw a light line down the seam.
Use the pencil line to set the CWF drop and drag it down the pencil line.

I'm aware many builders use thinned auto body filler for body tube seam filling. Right now I'm using the CWF with good results. I know it sticks better but I'm concerned about fumes from the auto body filler.

TIP: When sanding the CWF to surface, sand from side to side down the length of the tube, opposite the spiral direction. This helps leave more of the filler in the seam.
If you were to sand around the tube, directly following the seam, you could knock some of the filler out of the seam trough.