Aerotech Mega Initiator #89541, Part 7, Prepping More Parts!

I know there is a LOT of parts prepping - 

Ask any wood worker. The secret to a great finish is good surface preparation.

   

Here's that inside corner on the leading edge of the fins.

On the top picture - 

With the primer shot, you can see the mismatch of the rounded leading edge at the center of the angle. Some corrective sanding was done.

Here's the same corner after a directed shot of filler/primer. More careful sanding should get things in line.

The fin after the second coat of filler/primer - 

There were some small lines that needed some CWF and more sanding.

It seems every slot was a hair too narrow.

The root edge notches and the fin slots in the body tubes were widened for a better fit.

I could slide my sanding block into the slots using 220 grit.

The fins were test fitted. 

The joint of the body tube and root edge was very good now, tight enough with no distorion of the tube..

Aerotech Mega Initiator #89541, Part 6, Fin Filling

One of the fins had a knot hole fill.

It won't be noticeable with an easy CWF fill and sanding.

This fin will go on the flying build.

Here's that inside angle trouble spot I mentioned earlier.

When sprayed with filler/primer you can better see what needs to be cleaned up with better rounding.

The root edge and fillet areas were taped off for the filler/primer spraying

The fin in back is before sanding,

The fin in front is after sanding with 400 grit.

Here's a close up of the sanded fin surface. 

It's easy to see the gray filler left in the shallow grain.