This thread will cover build instructions for 3D print Indianapolis class 3 cruiser for IRCWCC. placeholder for materials and tools list placeholder for print settings placeholder for link to files Step 1. Print and cleanup hull Once hull sections are printed, each one needs the supports removed. I use a range of pliers, chisels, and razors to do this. Ensure you remove all supports prior to joining the hull pieces, as access is more difficult once the pieces are joined. Once all supports are removed, I sand the joining surfaces so adhesive has more to stick to. Also drill out the joint holes with 1/8 or 9/64bit. Drill out holes for stuffing tubes to at least 9/32. Step 2. Stuffing tubes and struts I like to insert the stuffing tubes while assembling the hull, since glue will go into the stuffing tube holes when joining pieces. Materials: 2x 9/32 OD, 12” K&S brass tubes 1x 1/16”x1/4”x12” brass bar. cut the tubes to 9.5” in length, ensure the cut end is square and deburred. Cut the bar in 3.5” lengths (2x). Bend the brass around a 9/32” drill but using pliers, vice grips, or vice. end result shown Next test fit the stuffing tubes and struts to ensure they fit. You might need to trim the strut so it fits in the hull recess Step 3: Glue hull together Materials: Adhesive: either e6000, plastic bonder, or epoxy Fasteners: 6-32 pan head screws, 1/2” long with nuts and washers I start stern to bow, joining aft two pieces, along with stuffing tubes and struts. Insert stuffing tubes while adding e6000 to the outside of tube. Avoid filling the hole first as the tube will pick up glue. Glue joining surface and fasten aft two pieces. Finish inserting tubes, extend beyond the strut position, then back the tubes into the struts. Put e6000 between tube and strut. End result should look like this On inside of hull, tube should extend in 1/8” from edge of plastic Continue forward joining piece by piece. I put washer on screw before inserting repeat until all hull pieces are fastened together End result Step 4. Glue strut ends Fill the strut recesses in the hull with plastic bonder or similar. Once dry, stuffing tubes should be solid
Step 5: Drag shafts materials: 1x 9/32” x 12 K&S brass tube 2x 6-32 x 1 1/2” pan head screws k&S Brass tube 3/16, 7/32, 1/4” OD. All 2x by 1/2” long tools: brass soldering: torch, flux, solder Here are materials Cut the 9/32” tube to 5.5” and the smaller tubes to 1/2” long. Grind the pan head screw down slightly so it fits inside 9/32 tube now prep to solder together. first I wrap solder around a screw and snip to get small pieces/loops next I put flux on screw and insert into 3/16 tube. Flux will draw the solder in put flux on outside of tube, and slide on next size tube. once all short tubes are on, put into 9/32 tube. Put small pieces of solder in open end and slide down to the screw so they will melt heat with torch until solder melts and flows. once done with both, put tap over threads to ensure threads are clean next I put a 1/4” OD material in the open end of shaft so it won’t fill with water. Glue in with e6000 finally glue the shafts in with e6000 or plastic bonder. Fill the printed recess, and put bonder around shaft before inserting into the plastic strut
Step 6: cut and prep shafts materials: 2x 1/8 diameter by 12” stainless steel shafts 4x 1/8” ID, 1/4” OD oilite bushings 2x printed props, 1.25” diameter by 2x Dubro shaft collars E6000 Plastic bonder Tools: Dremel with cutoff disc Drill Hammer glue in the bushings with e6000 cut shafts to 10 and 9/16” next glue the props on the shafts. I use plastic bonder here. Pre drill props with 1/8” bit. Gently tap in shaft with hammer wipe off excess bonder before drying now I grind a flat spot for the collar and dog bone ends
Step 7: Rudder and rudder mount gears materials 1/8” stainless steel rod. 3” and two approx 1” 5/32” OD brass tubing E6000 or plastic Bonder start by assembling the rudder. I have several other posts with these pictures. First bend the stainless steel to fit the curve in the rudder. Sand the two surfaces and then glue together Next cut brass tube into lengths shown for the rudder mount gears. Based on the distance from the rudder servo to the rudder post, two idler gears are used. Alternatively you could use chain and sprocket Insert the tubes into the holes on the rudder mount (centerline) here are the shafts test fit the tube for rudder post should stick out 1/8” from hull This shows throw of the rudder next up is putting the pivot rods into the gears. cut stainless rod scraps from drive shafts to about 7/8” glue the posts on with e6000 For the rudder gear, I heat-set a dubro collar into the gear so the set screw has something solid. here is collar and gear hold collar with pliers or vice grips and cut grooves with Dremel Drill 1/8” hole into scrap wood. Put scrap metal rod in hole. This will guide the collar on. I use Allen key in the hole of gear to align the hole in the collar heat up the collar with mini torch or soldering iron, then press into gear. If it gets stuck, use soldering iron the heat up more I use 4-40 stainless set screws 1/4” long. this holds the gear to rudder. Grind flat spot on rudder shaft for set screw to grip attach servo horn to servo gear. I use screws, but can also just glue tap 6-32 holes in the servo mount Here is servo with 6-32 1/2” screws holding in place this is just test fit, I’ll add more detail on servo selection and final install later
Step 8: Pump mount materials 3x 6-32 x 2” screws and nuts E6000 or plastic bonder simple step. Put screws through holes into the pump mount piece. I had to get 3” and cut to size (about 1 7/8” total length side view. On hull 1 I started with 4 posts, but needed to remove one to be able to get pump in and out. That’s a benefit of not posting files yet until I confirm it actually works. But for now I’m not afraid of a Dremel so I cut away 1 post and will fill the hole Glue the screws into the bottom of the hull. I covered with a layer of fiberglass cloth because my hull had some very thin areas that were holes. These have been fixed in the model. You can see the 3 screw heads under the cloth
Step 9: Internal armor part 1 Materials Shower pan liner (1ft) from Home Depot/lowes E6000 Here is shower pan liner. We used to use this as internal armor alone. I use this to cover the plastic armor parts to slow down bounce-backs and preserve the plastic a bit I cut out strips that are 3/4” high to go at the top of the windows. Glue on with e6000 and use clips to hold on I also cut out a piece for the bow plate and glue on Here is end product
Step 10: subdeck magnets and hold downs Materials: 1/4” x 1/8” rare earth magnets 6-32 heat set inserts Epoxy, e6000 or plastic bonder Tools: Mini torch Channel locka Needle nose pliers to hold while heating start by putting the heat sets in for the four holes for aft deck. I use mini torch for this here are heat sets, from McMaster. I put a screw into them to hold on while heating up Heat with torch and insert so top is flush with deck if they don’t go in all the way, remove screw and then heat with soldering iron to push in. here is end result Magnets shown on next post
