Semroc Laser X, KV-33 Build, Part 5, Fin Filling & Gluing

The 1/16" thick pieces (upper fins, engine strakes and launch lug) were set on a taped board for a good shot of filler/primer.

Here's the four larger fins, ready for their filler/primer coat.

Notice the root edges are set close together to keep the filler/primer paint out. Keep your gluing surfaces "raw" for a strong bond.

This is one of the upper fins - 

On the left is a fin with the filler/primer shot and dried.

On the right is another fin with the filler/primer sanded down using 400 grit. Any balsa grain that was left after the CWF sanding is filled with the filler/primer. Two steps and the balsa grain is filled. 

The fin locations are marked with pencil .

TIP: NEVER use an ink pen to mark fin positions. The ink will bleed through paint and show under finish colors!

Note - The body tube got the same two-step fill of CWF and filler/primer. Look close, you can see some gray filler/primer in the tube seams.

I used the root edge of a fin to mark the high and low ends of the fin.

The tube was roughed up down the vertical pencil line stopping before the high and low end root edge marks. 

You only have to rough up the tube - don't sand deep!

The fins were glued on.

Here the launch lug is placed even with the end of the body tube.

I use my sanding block to even up the lug end.