Micro-Maxx Estes Fat Boy, Part 4, Nose Cone Plug

I didn't have a shoulder base for the old plastic nose cone.

Using the same material as the centering rings, trace around shoulder end of the nose cone with a sharp pencil.

Cut just inside the pencil line with scissors.

Round out the base with 220 grit on a block.

Sand, check the fit and sand some more until you get a slip fit.

Glue a reinforcement strip to the inside.

Punch two small holes for shock cord attachment.

Tie a short piece of elastic with a square knot.

The plug is set just under the edge of the shoulder base. By insetting the plug under the edge allows you to add a glue fillet.

The glue fillet was made with Fabri-tac glue.

Micro-Maxx Estes Fat Boy, Part 2, Centering Ring Fit

Left side picture:

Two uneven, rough cut rings stacked for gang sanding to fit.

Right side picture:

A 1/4" diameter dowel was slipped in for strength while sanding the ring sides even

Sand, test fit and sand some more until you get a good friction fit in the BT-20 tube.

The finished mount with a MMX motor slipped inside to check the position of the engine block slid in from the top.

The finished mount will be glued in with the motor extended a little beyond the edge of the BT-20 tube.

Micro-Maxx Estes Fat Boy, Part 3, Centering Rings

I sure the small rings are available somewhere, I didn't have them. Why wait for an order. I'm cheap so I'll make a few.

A 1/4" punch was used to start the inside ring hole.

The hole was widened using a knife spin followed by a half round diamond file.

The fit was checked with the yellow engine tube I had.

Center the BT-20 tube over the cut just made and trace with a sharp pencil point.

Cut just inside the pencil line using scissors.

Final fitting in the next post -

Micro-Maxx Estes Fat Boy, Part 1, Parts

The picture above is close to the full size MMX build!

This is a spare parts drawer build.

The only parts missing are the centering rings.

Those will be hand cut out of the white framing mat material. 

The nose cone is a leftover from a retired rocket, already painted silver.

Decals have been drawn up, I doubled the F, A and T letters for both sides of the fins. The original kit only included decals for one side of the three fins.

Kevlar line and tablecloth streamer.

Fins will be cut from 1/16" scrap balsa.

The launch lug is a BIC pen ink tube, cut from the end where there was no ink.

The yellow motor tube and engine block are original Quest MMX parts.

Estes Mini Arcas, #2441, Finished

I built and masked the original BT-55 version of the ARCAS.

To be honest, this BT-20 version wasn't a fun build.

The small balsa fin support pieces are hard to form out of balsa. 1/16" thick fins don't allow you to sand a diamond taper. 

The red color mask was difficult on the downsize model.

Here's the upper end and nose cone showing the mask.

The ARCAS is a sleek rocket with a great looking red/white job.

I wish it were the original, easier to detail and paint BT-55 size.

Estes Mini Arcas, #2441, Part 20, Fin Taper Decals TIP

In April of 2024 on TRF, Neil W made a great suggestion about simulating fin tapers on the Mini Arcas.

The fins are only 1/16" thick, sanding a diamond fin taper would be very difficult.

TIP: Neil suggested a light gray printed decal set onto the rear half of the fins.

I had been wanting to try this ever since - Thanks Neil!

I drew up some fin tapers with a 10% black. Extras were copied and pasted - I did need them.

I'm not releasing this decal for home prints. My fin supports are a little thicker than the kit supplied pieces. My decals probably wouldn't fit your build. 

It's a challenge to fit the decals to the root edge details.

Add the fin fillets and they'll require individual fitting. Good thing I made the outside and trailing edges a little wide.

Here's the finished look. From a few feet away, the illusion is good. 

Maybe it's a bit dark. If a 5% gray were available I could have used that.

The overhanging edges were trimmed off with a "sawing" motion using a single edge razor blade.

Estes Mini Arcas, #2441, Part 19, Decals

I referenced Peter Alway's book, Rockets Of The World to double check the decal placement. ARCAS reads up, the ATLANTIC RESEARCH CORP. reads down on the other side.

Sight down the body tube to check the vertical alignment of the long decal.

TIP: Many people post about using a drop of dish detergent in the soaking water. They claim it allows a slippery decal, easier to position. 

On YORF, Micromeister brought up a good point. The dish soap can dilute the adhesive on the backside of the decal. 

Wet the area where the decal will be placed. Dip your finger in the water and rub the painted body tube leaving the (painted and sealed) tube a bit wet. Then slide the decal off the backing onto the wet model.

Here's the ARCAS decal between the two small lugs.