Estes Apollo Little Joe II Build, Part 4, Tube Prepping

Only the top of the main body tube needs the seam filled. The lower half will be covered by the vacu-form wrap.

With the wrap even with the bottom of the tube, a pencil line was drawn around the top edge.

I started with my normal seam filling with Carpenter's Wood Filler. This was sanded down to surface with 220 grit on a block.

Masking tape was placed inside the top of the tube to keep the primer/filler out.
TIP: Before applying the tape, set the sticky side down on your pant leg and lift a few times. This leaves filaments on the tape making it less sticky. There is a chance that a full adhesion tape might lift the inside layer of the body tube.

Here's the before and after sanding down the Duplicolor Filler/Primer. I'm building two kits.

One single application of the Carpenter's Wood Filler fills almost all of the seam. One sanded coat of the Primer/Filler fills any remaining seam recesses.

On the forums I read about other builders doing four rounds of spray filler and sanding to fill the body tube seams. To me this is a lot of extra work.
One application of CWF and sanding, then one fairly heavy coat of Duplicolor Filler/Primer and sanding does the job! Two filling and sanding rounds instead of four saves time.