TLP Pershing #K046 Build, Part 3, Engine Mount

Anytime you install a replaceable Kevlar tube, cut it back away from the top of the engine mount tube.
It doesn't have to be flush with the top of the centering ring.




The engine mount is glued into the BT-80 "Exhaust Tube".
Recess the lower ring 1 3/4" up from the end of the tube.

My square ended steel ruler works well as a depth guide.



Looking ahead, 
Check out the shroud line locations on the oblong parachute.
There are six "corners" but eight shroud line locations.
All the shroud lines are attached at an angle.

TLP Phoenix 1.6" Fin Brackets

The cardstock Phoenix fin brackets fit into the fillet area of the upper fins.
Here I'm scoring the fold lines with the back of a single edge razor blade. The back metal guard of the blade is the right thickness and contour for to a sharp fold.
Notice I've stuck a few layers of masking tape over the sharp side of the blade. (now facing up)

It's easier to score the fold lines before cutting out the piece, especially on something this small.

When scoring a fold, I prefer not to cut halfway through the cardstock like most instructions tell you to do. By lightly pressing and running the back of the blade down the score line it's almost like blind embossing. It's a "pre-fold" of the line.

Before scoring, it's a good idea to use some sandpaper on a block over the back edge of the blade to remove any burrs and insure it is straight.

Sorry about the dark picture, click on the image for an enlargement and you can better see what I mean.

TLP Phoenix 1.6" Fin Fillets

The Launching Pad Phoenix kit has cardstock "brackets" that cover up the longer front fin root edge joints. I really only have to be concerned with smooth fillets on the rear, square fins.

After two fillets of white glue, I could still feel roughness when I ran my fingernail over the dried fillets.

To smooth out the rough areas I dip just the tip of an old hobby knife blade into thinned Carpenter's Wood Filler.

Drag that drop of filler down the fillet joint.

I've never been able to form 400 grit sandpaper into a small sanding circle without creasing it.

I didn't want this fillet to be a sharp concave 90 degree corner, more a tight small curve.

I wrapped the sandpaper around the tip of a sharpened dowel, leaving the dowel tip just inside the sandpaper edge.

The last picture shows the fillet being sanded smooth.

Because the filler shinks when drying, I may have to go back and touch up with a little more filler and sanding again.

TLP Phoenix 1.6" Fins Lined Up

After removing the Posicle sticks and clothes pins, here's the in-line fins.

Next up are the fillets.

TLP Phoenix 1.6" Lining Up Fins

I wanted to be sure the tops of the upper four fins were all lined up.

The lower four fins were easy enough, they were flush with the bottom of the body tube.
The larger upper fins are spaced 5/8" from the lower fins.

After the first upper fin was in place (at 5/8" spacing from the lower) I made a paper wrap around the top of the tube. It was just tight enough that I could slide it up and down and against the small, square leading edge of the upper fins.
If you look closely, you can see the penciled fin alignment line. I don't draw lines down the entire length of the tube. Sometimes pencil lines will show up through a light base color like white or yellow.


After the fins is set in place, I slid the paper wrap down onto the leading edge of the fin already in place.

Even though I "eyeballed" the initial placement of the second fin, I still had to slide it forward to match the first fin leading edge placement.

TLP Phoenix 1.6" Already Started

Here's how I lined up the fins on my TLP Phoenix.
Before gluing the fins in place:

Body tube seams were filled with Carpenter's Wood Filler and sanded smooth. When filling body tube seams, I mix the CWF a little thicker than when I would if filling wood grain. It seems to stay in the seam a little better this way.

Rustloleum Gray primer was applied to the body tube and sanded smooth with 400 grit sandpaper.
Fins were filled, sanded, primed and sanded again before gluing to the body tube.

Fin lines were drawn down the body tube. Using a knife blade, I scraped away the primer where the root edges would be glued.

The bottom four fins were glued using the "double glue" method.


To line up the upper and lower fins, I used Popsicle sticks (tongue depressors) and clothes pins.
I've been filling and priming fins off the body tube for years now. It's near to impossible to sand and fill fins with white glue fillets in the way. The Carpenter's wood filler is water soluble so white glue will permeate it when gluing the fins in place. Still, for the best adhesion, keep that root edge clear of CWF.