Disappointed - Badly Done 3D Print!

I want to build a Estes Sandpiper, Kit #1389. It requires the plastic PNC-50S nose cone with the "finlets" on the side like the larger Jayhawk.

I didn't want to pay a premium for an old unbuilt kit. After having some beautiful 3D parts made for the recent Centuri Skylab build, I decided to have one of the online 3D printers make the nose cone for me.

After a search, I found Jack Hydrazine had submitted 3D files for the PNC-50S nose cone to thingverse.com. Thanks Jack! The hard work is already done . . .

After too many text messages, and a assurance that the sizing was correct, I used PayPal funds to pay for the nose cones. Two nose cones and two bases for $18.00

On the right is what I received. The outside diameter is only .60". It should have been larger, at .976" diameter to fit a BT-50.

Here's a closeup, check out the ridges.  

The finlet trailing edges are rough, looks like my dog chewed on them.

I'm not mentioning the vendor name yet - I'll give them a chance to correct the mistakes.

Micro-Maxx Estes Fat Boy, Part 6, Fin Grain & Body Tube Seam Fill

Before printing the decal (and wasting a decal paper sheet)

A test sheet was printed on 20 lb. copy paper to check the fin decal sizes.

These are a tight fit with an even border around the custom drawn letters.

The fit seemed good and the water slide decals were printed.

Here's the fins after a CWF fill and sand with 400 grit.

Filler/primer spray follows then more sanding to surface with 400 grit.

The fin gluing line had the filler/primer scraped off.

Filler/primer seals the surface. Wood glues won't stick as well on a sealed surface.

After scraping, redraw the root edge pencil lines.

Estes USS Enterprise #1275, Part 42, Painting The Details

The raised, thick cardstock rectangles should have been painted the darker gray and then glued on the model. 

These aren't difficult to mask now, it's just some extra work that could have been avoided if I'd planned ahead!

The rectangles were outlined with Sharpie inked Scotch tape.

Brown tape widened the mask,

Plastic grocery bags covered the rest of the model.

With the masks removed there is very little touchup needed.

Estes USS Enterprise #1275, Part 41, Painting The Impulse Engine Details

I'm not good at hand painting. This light gray impulse engine has straight lines and plenty of curves. I decided to mask and spray.

Here's the top - using many small piece of Sharpie marked Scotch tape.

The view from the bottom.

The thin mask border coverage is widened using brown tape.

Press a Q-tip around the edges to (hopefully) seal them.

A plastic grocery bag covered the rest.

After the tape was pulled - 

As expected, there was touchups.

The final look came out okay.
 

Estes USS Enterprise #1275, Part 40, Repainting The Propulsion Caps

I'll be bouncing around two different builds for a bit -

Here's the instruction illustration, the shaded area designated "dark gray". The caps are actually a lighter gray.

I first tried Ace Machinery Gray, but it was too dark!

I repainted it using Ace Light Gray. Now it is much closer to the color shown in the original T.V. model displayed at the Smithsonian.

Those raised rear rectangles (see the instruction drawing above) should have been painted off the model to avoid another mask.

The elevator was hand painted light gray.

The port side running light was painted red. I don't have any green paint so the starboard side light will have to wait.

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.

Estes Mini Arcas, #2441, Part 18, Launch Lugs

I didn't glue on the lugs before painting the rocket body. 

I thought they would be in the way of the complex mask.

Sometimes I skip the launch lug fillets. Bubbles are a pain!  

     

I wish the lug placement were different. I would prefer the the ARCAS name decal not in line with the launch lugs. 

The lug glue areas were scraped down to the body tube. Don't scrape too wide, you'll want the lug to cover where the paint was taken off.

The glue line on the small lugs is narrow and even down its length.

Set down the glue line and even the line with a fingertip. Use white glue because it dries clear.

Both lugs are glued in place. 

Even without a glue fillet, they aren't going anywhere.

Estes USS Enterprise #1275, Part 39, Painting The Propulsion Caps

Painting the propulsion caps is a bit tricky. 

On the rim are three raised dots. I decided to mask these, leaving them along with the shoulder ring, a light gray.

This picture shows a marked Scotch tape mask "dot". The next picture shows how it was cut.

To mask the raised dots, I marked a strip of Scotch tape with a wide Sharpie. Wipe off the excess ink with a paper towel.

When punched, you will be left with a perfect circle. Lift it off the dot and hold it on your knife tip.

Place the dot onto the cap while still on your knife tip.

The sides were masked with brown masking tape. Normally I'd use Scotch tape for the mask, but the shoulders of the cap is tapered and Scotch tape doesn't flex. Both brown and blue masking tapes have a little "give".

The back caps were masked using marked Scotch tape.

Here's the caps after the tape was pulled.

That gray might be a little too dark.

The dome color suggestions are copper, bronze or bright orange. I went with Rusto copper.

Thinner, Lighter Centering Rings?

If you don't have .050" thin cardstock centering rings, You can lighten the engine mount a bit by "halving" 5/20 or 20/50 rings.

On the left is a 5/20 thick centering ring.

Start by drawing a pencil line around the outside of the ring.
 

Using a fine razor saw,

Carefully cut around the ring following the pencil line.

Clean up the rough sawn face using 220 grit on a block.

Here's a single ring, split in two.

Maybe not as light as flat white cardstock rings, but still a reduction of weight in the tail end of the rocket.