[RocketsNW] vacuum bagging fins

[Carl Degner]

A couple weeks ago, I asked about various peoples experiences/suggestions
vacuum bagging fins.  That was my weekend project.  The last fin just went
in the bag.  I wanted to thank everyone for their suggestions and sources of
supplies.

I ended up using the 36" bagging tube along with the quick clips available
from ACP Composites.  I heard that the tape can be tough to seal up.  The
quick clips make sealing up the tube a breeze.  When hooked up to my Edwards
E2M2 two stage pump, I never once had a problem with leaks.  One yard of
tube get me through two "practice bags) and all three fins.

The fins are made from 1/4" 10ply aircraft plywood and were skeletonized
with one horizontal brace and one vertical brace left in place.  I then cut
pieces of 1/4" nomex honeycomb to fill the voids.  1/32" 3 ply plywood was
then laminated on both sides.  This by it self seemed pretty strong.  To add
additional strength and rigidity, I laminated one 5 oz. layer of 4HS kevlar
cloth from US Composites and a layer of 6 oz. FG on each side.  Using rayon
peel ply and fabric store polyester quilt batting, completed my setup.  The
peel ply has left a nice finely textured surface that will be good for
adhesion of fillets but still easy to fill for paint.

IF you've ever avoided Kevlar because it is so tough to cut, with the right
scissors, it is easy to do.  I bought a pair of Fiskars titanium nitride
coated shears for $22 from John A. Eberly that cut kevlar cloth like butter.
Both blades are finely serrated which keeps the fibers from just slipping
out the jaws as you try to cut.

Again, thanks for everyone's replies on ideas.

Carl