Estes Time Warp Build, #7321, Part 7, Gluing & Filling The Fin Tips

The fin tips and fins had the balsa grain filled and sanded.

Filler/primer and sanding followed.

I used a small diamond file to slightly open up the slots to a friction fit over the fin tabs.

The fin tips are glued on.

There is now gaps around the fin tab joint.

This joint required additional filling,

first more CWF and sanding flat with a block.

The backs of the shield tips are masked and the flat face got a shot of filler/primer and sanding with 400 grit.

Once the fins are glued onto the BT-5 cluster tubes, 

Masking will be tight to separate the black and yellow paint on the inside of the "T" fin.

I sprayed some white undercoat on just the fin tip face and the underside joint.

Notice the root edge is masked off with a narrow strip of tape.

Estes Time Warp Build, #7321, Part 6, Fin Fitting & Fill

The tube seams were filled with CWF and sanded to surface.

The BT-55 had a definite seam, the heavy walled BT-50 was very tight.

After the fin tips were glued together, I tried a test fit on the main fin.

I wish the fin tabs (sticking into the smaller "shield" fin) were longer so you could sand them to surface after gluing them on. With the tabs slightly recessed there is more to fill.

Laser cutting burns through at a slight angle.

Look close at the right side of the root edges.

I sanded and evened the burned edges so they would glue on perpendicular to the body tube.

The fins have laser cut "slots" running parallel to the leading and trailing edges. I decided to leave them in and fill the slots with CWF.

Why leave them in?

The rough laser cut slots would be difficult to fill and sand. The visible edges would be rough. The design is interesting enough without the open slots.
 

Estes Time Warp Build, #7321, Part 5, Upper Centering Ring

Here's the upper laminated centering ring,

glued 1/2" from the bottom of the BT-5 tube cluster.

The instructions say to add glue fillets down and between the three tubes.

TIP: I wouldn't do this, it's a long, deep joint. When the glue dries you'll have bubbles and an uneven fillet.

I used a few drops of glue to fill the small center gap. This will block any ejection charge escape.

Years back we used "tissue/glue putty" to fill gaps like this. Tissue/glue putty is a mix of glue and tissue torn into very small pieces. It makes a strong gap filler.

This gap is small, if it were larger I'd make up some tissue/glue putty.

To read more about this gap filler: CLICK HERE 

This top and bottom glue fill also strengthens the mount.

Estes Time Warp Build, #7321, Part 4, Centering Ring Laminates

The center triangle of the centering rings will probably break off. There's not much to hold it in the center.

I'll show how to block the hole (and the ejection charge) in the next post.

When laminating the two sets of two rings, 

use one of the BT-5 tubes to check the alignment.

Don't glue the tube to the rings (yet), use the tube to be sure all three holes are lined up.

The instructions suggest sliding the ring down from the top into a glue ring.

For a cleaner build and less visible glue -  

I slid the centering ring up from the bottom pushing the glue ring up. It's a cleaner visual outside joint on the finished model.. 

You don't have to use much glue, you can always add a glue fillet later.

Estes Time Warp Build, #7321, Part 3, Engine Blocks

Jim Flis (Fliskits) gets credit for this engine block setting idea calling it the "Block and Tackle.".

TIP: The mini motors (friction fitted) extend 1/4" out the rear of the BT-5 tubes. 

A 1/4" strip of masking tape is wrapped around and even with the end of the yellow spacer tube. 

This tape ring stops when it hits the end of the tube. 

All three engine block will be at the same depth.

The instructions the engine block glue line at 1" inside the tubes.

I'd recommend using a dowel pencil marked at 1 1/4" to apply a ring of glue inside the tube.

Apply the glue ring, slide in the engine block. Use the taped yellow tube to set the ring depth.

The three BT-5 tubes are ready for the centering rings.

Estes Time Warp Build, #7321, Part 2, Paint Plan & Engine Tubes Fill

Planning ahead!

If you want to paint the rocket in the face card colors, paint the build in sections before gluing it all together.

The BT-5 cluster tubes are yellow and would be difficult to paint if glued into the gray BT-55 tube.

That yellow adapter could be painted before gluing into the white BT-50. Same goes for the gray nose cone. Paint them before gluing together and get instant "masks" or color separations. 

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The lower centering ring is glued 2" down from the tops of the BT-5 motor tubes. I filled the tube seams below that.

The seams were shallow, here you can see the pencil lines where they could be felt.

CWF was used to fill the bulk of the seams and sanded smooth.

The upper 2" (glue area) was masked off and the low end sprayed with filler/primer. Sanding this down filled any remaining seams.

Estes Time Warp Build, #7321, Part 1, Parts

A new mini-motor cluster rocket!

I recently picked up a bunch 13mm motors. This model would be a good way to burn through some black powder.

The Estes Time Warp has three BT-5s motor mount tubes (left side, in yellow) joined to a BT-55 (gray tube). A 55/50 adapter joins to a heavy walled BT-50 (unusual) and finally the gray nose cone.

The parts of interest:

Mentioned earlier, a heavy wall BT-50

The new self-adhesive Estes shock cord mount

A laser cut 3/32" thick balsa sheet

The four centering rings - 

The pairs are laminated to make two thicker rings.

That small center triangle is very close with not much to hold it onto the assembly.