Epoxy and ABS

The Nose

just fit in a standard makerbot replicator build area. I printed one with low fill (shown right) and test-fit the part, made modifications and printed a red ABS version using my I designed the nosecone to be structural, removable and protect the motor mechanicals while sloshing water out of the way. Both the nosecone and the end cowling were designed tofit in a standard makerbot replicator build area. I printed one with low fill (shown right) and test-fit the part, made modifications and printed a red ABS version using my home-contraption



The quirk with large prints:



THEY TAKE A WHILE. At the time, the 3d printer robot was down for repairs, so I was fortunate enough to use the fantastic replicator over in Charles Guan 's WUNDERBAR LAB. The build time was a full 27 hours for the rear nosecone assembly. Poor makerbot! This was a full ABS part, with a 30% fill ratio. It occupied the full build platform, and came out beautiful.

The cowling

ITS PRINTED AND BEAUTIFUL, now to add some hardware and internal mechanical parts! The cowling itself holds an internal shaft bearing, preventing prop-wobble as it is a full 8" away from the motor mount.

Adding the extension and adapter

The motor exits with a 12mm shaft, and as this is fairly short for throwing a propeller onto, a coupling and extension bar is added on to the rear cowling assembly. The bearing's purpose is shown below.

The inside of the rear cowling

The bearing holster is shown at the far bottom of the inside of the rear cowling. The four surrounding bolt holes pass through and connect to the captive plate that holds the bearing in place.

Rear Bearing and holster

With the self-digging-in screws in place, and sliding the output shaft into the bearing assembly.

Sliding everything together



Checking alignment and making sure everything clears.

Torchy mc-torch bolt



using a propane torch, set as low as possible, I heated the torx screws, then rapidly screwed them in place. This formed a tapered fillet and melted the bolt to the part. It came out looking excellent.

WEAPONS



Ok its no chain sword , but it sure looks nefarious. Shown is the thruster with the 3d printed propeller, printed by the home-robot-printer

Pre Epoxy Sanding



With the comlete print, the parts were sanded, then wet-sanded (to eliminate dust). Shown (right) are the sanded nosecone and rear cowling. After sanding, i applied a layer of 2 part epoxy to provide a heavy outer coating for the part, absorbing energy from impacts and preventing the plastic from shattering too easily. I tested mixing acetone in with the 2 part epoxy and it resulted in a bit of cracking, but seems to hold up well to impacts.

Epoxy and Paint

After a fair amount of drying, from the suggestion of the ever-awesome Adam , i used krylon plastic paint, coated the parts, and 'baked them' next to some bitcoin mining rigs. The paint seemed to bond well to the bare abs part, but not as well to the epoxy'd nosecone.

So Fancy

With all the parts mocked up i layed the thruster on the cleaned non-ferric stained lab bench for a beauty shot.

Mounting Bracket



To test the thruster, I needed a quick mounting assembly. I tapped four 1/4-20 screws into the front and rear plat and made a 2 bar extension to allow for outdoor testing . A Bayley is used for scale (far right).

Feeding through the cabling

The bulkhead connectors worked great for getting the wires out from the inner motor, next i used bullet connectors and 10 gage super-flexi wire to feed the three-phase feed up and out from the motor.

Thruster wiring on the apartment-bench

