Fab Lab Tulsa 1 (FLT1)




About: The more mistakes I make, the more knowledge I gain.

Fab Lab Tulsa (https://fablabtulsa.org) asked me to a design a boat for their "Boat Moat" challenge during Maker Faire, Tulsa on August 25, 2018 and I gladly accepted the challenge! After a week of design and testing, redesign and more testing, FLT1 (Fab Lab Tulsa 1) is ready to race.

FLT1 fits inside the maximum allowed dimensions of 8 by 5 inches, and, as required, is powered by a rubber band. Weighing in at a total weight of 60 grams (2.1 ounces), as can be seen in the video, it can really move. I tested my FLT1s using single rubber band, but...

As usual, I probably forgot a file or two or who knows what else, so if you have any questions, please do not hesitate to ask as I do make mistakes in plenty.

Designed using Autodesk Fusion 360, sliced using Cura 3.2.1, and printed in PLA on an Ultimaker 3 Extended.

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Step 1: Print and Assemble the Parts.

FLT1 requires a 10 by 15 by 4mm ball bearing (I used a ProtekRC PTK-10046 with the rubber seals removed), and a rubber band (I used a Guillow's 7 by 3/32in rubber band).

I printed my parts on an Ultimaker 3 Extended.

"Hull With Graphics.3mf" is the dual extrusion hull I printed in Ultimaker Yellow and Ultimaker Red PLA filament at .15mm layer height and 20% infill with no supports. I've included the file "Hull.stl" for single extrusion.

"Winder.3mf" is the dual extrusion propeller winder designed for use in a cordless drill (yes, cordless, please do not use a corded drill near water!). I printed this part in Ultimaker Yellow PLA (winder body) and Ultimaker Polypropylene (winder insert) at .15mm layer height and 20% infill with no supports. I've included the files "Winder Body.stl" and "Winder Insert.stl" if you want to print them individually and press them together. If you choose this method, you may need to slightly scale down the X, Y dimensions of the insert, or slightly scale up the X, Y dimensions of the body, in order to press the two components together.

"Propeller.stl" is the dual extrusion propeller printed with Ultimaker Yellow PLA and Ultimaker Breakaway (for support) at .1mm layer height and 20% infill with supports.

See the video for how I assembled my FLT1s.

Hope you like it!



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    8 Discussions


    Reply 1 year ago

    I know this sounds ridiculous, but I've had some of my designs manufactured without my consent by out of country companies who then proceed to sue me for infringement on "their" designs, thus my attorneys recommend I no longer publish the cad files except for educational (e.g. proven educational institutions) purposes.

    I am indeed sorry, but I didn't create this environment, I just have to live in it...



    Question 1 year ago on Introduction

    How much drag does the rubber band cause, I bet you would get better run if it was consealed in a tube, plus the resistance of the water tension may also cause drag and a small loss of over all power. Cool I deal though.

    1 answer

    Answer 1 year ago

    Thanks, I'm glad you liked it!

    I did not perform a drag test for the rubber band, but I did perform a weight and buoyancy test and, with the addition of a tube to contain the rubber band, the waterline rose to the point where 7/8ths of the hull was below the waterline which of course, dramatically increases drag. The goal of a boat like this is to minimize contact between the hull and waterline (e.g. get the boat on "plane" as fast as possible), and for a rubber band powered boat, this is the best I could come up with.

    Hope that helps!



    Question 1 year ago

    Sorry to be off topic, but I was wondering if your 3d printer will print an etching mask onto copper clad pcb? I just didn't know who else I could ask. Thanks

    2 answers

    Answer 1 year ago

    You would probably be better off with a CNC engraver for that task. Back in the early 90's I was running mastercam and a CNC mill to make pcb slow and tedious, but it got the job done most of the time.


    Answer 1 year ago

    No problem at all!

    The printers I use do print quite small and accurate but I’m not sure how well the materials I use would remain attached to the copper during an etchant bath.

    Using the materials on light sensitive PCBs may work better, you’d just have to print in a darkroom environment .

    Ultimaker told me there is conductive filament available (not from Ultimaker), but from my understanding, it is resistive but I don’t recall an “ohms per inch” value.

    Good luck, and keep me informed of your progress, sounds very interesting!



    1 year ago

    Manic Monday I don't think you could accurately print a PCB mask unless the areas between traces are big say at least 2mm. otherwise my 0.5mm print head may struggle smaller print head sizes are available but I haven't personally tried these. the next problem would be sticking the print to the PCB while you etch. printing directly to the PCB may be possible but probably won't stick on its own while etching. some form of glue may do it. You could maybe use a print as a UV mask as long as you use an opaque colour of plastic.