Just because you can, doesn't mean you should

You can 3D print a lot of things, but that doesn't mean it's wise.

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3D printing is challenging the ideas of modern manufacturing. From rocket engine parts to prosthetics, 3D printing is opening many doors to the home builder. We have a few printers around the office and they are great for making small brackets, enclosures, and turtle action figures. But sometimes, ideas should just stay on the drawing board. For an upcoming episode of SparkFun Live, I sent out a quick, company-wide call for "terrible things to 3D print." Here is a sampling of what we got:

  • Scissors
  • Bike Lock
  • Trailer Hitch
  • Grilling Spatula
  • Exhaust Brackets
  • Hammer
  • Replacement Ladder Rung
  • Roller Blades
  • Screw Driver
  • Skateboard trucks
  • House Key
  • Dentures
  • TV wall mount
  • Soldering Iron Stand
  • Slap Bracelet

I'll choose a few winners, print them, and put them to questionable and amusing use during SparkFun Live. For those who want to play along at home and submit item suggestions, here are some guidelines:

  1. Prints will be done on the LulzBot Mini 3D Printer
  2. Printing material is HIPS
  3. Keep it PG

If I end up picking one of your inadvisable ideas, we're willing to mail you the aftermath - potentially in unrecognizable condition - when all is said and done. How's that for an incentive?!


Comments 131 comments

  • FSJ Guy / about 9 years ago / 12

    A multimeter with yellow sides

  • Wayne Seltzer / about 9 years ago / 10

    3D printer filament

  • kirby g / about 9 years ago / 5

    Soldering iron tips

  • Butterwaffle / about 9 years ago / 5

    Jars for your solvent collection.

  • SilenceIsGolden / about 9 years ago / 4

    Fireplace poker. Contact lens. Peton or carabiner.

  • andy4us / about 9 years ago / 4

    brake pads

  • Fusekiller / about 9 years ago / 3

    Engagement ring… I still have trouble seeing clearly out of my left eye.

  • EvPlasmaMan / about 9 years ago / 3

    A Shrubbery!!!

  • Colecago / about 9 years ago / 3

    One weekend while bored at my friend's shop we tried to design and print bubble wrap, with terrible results.

  • Member #104221 / about 9 years ago / 3

    one probably shouldn't 3D print instuction manuals, particularly not in a double sided, small font.

  • Skimask / about 9 years ago / 3

    Condom

  • AlanV / about 9 years ago / 3

    An artificial heart valve.

    • Blacklab1 / about 9 years ago / 1

      Don't say that too out loud--- someone will do it.

      • scharkalvin / about 9 years ago / 1

        That will actually work someday. 3D printed organs made from stem cells are a very possible technology.

  • sgrace / about 9 years ago / 3

    The Sparkfun SHOVEL.

  • A full set of drill bits

  • How about paper?

  • Member #673013 / about 9 years ago / 2

    A pipe.

  • ElegantElectrons / about 9 years ago / 2

    a nazi kicking a kitten...... oh wait, you want functionally terrible. A fire safe, chair leg, motor bearings, 3D printer hot end, pillows, a holster for your Heaterizer XL3000 with fake flames (wait, no, that would be awesome)

  • greggler / about 9 years ago / 2

    3d printed underpants are not a good idea

    • kirby g / about 9 years ago / 2

      Have to be careful, the 3d printed gnomes might steal the underpants.

  • Particle accelerator

    • xsk8rat / about 9 years ago / 1

      A cutaway view of a standing wave linac would look very nice on my desk.

  • Butterwaffle / about 9 years ago / 2

    Promotional gifts for the Pressure Vessel Manufacturers Association (PVMA, http://pvma.org/), a.k.a. My First Pipe Bomb kit, ages 5+.

  • Replacement wheel for my office chair

  • Member #363460 / about 9 years ago / 2

    Printing 3D printer filament would be redundantly redundant.

  • BeerCannon / about 9 years ago / 2

    a wood splitting wedge

  • Merlin.T.Wizard / about 9 years ago / 2

    Solid Rocket motor housing. Especially 5Z Class or higher. See http://en.wikipedia.org/wiki/Model_rocket_motor_classification

  • Blacklab1 / about 9 years ago / 2

    It would be interesting if there was a way to 3-D Print sand castings. Then you could make your own castings of something and then actually pour metal into the casting. I am thinking something like making a actual working turbocharger or something like that. Yeah plastic is nice, but it does not always hold up to the heat for some projects. (Yeah, you would have to do some tooling on your project, but this would bring you one step closer to having a working project.) I am almost thinking something like what you make for ballast for model railroad track- a mixture of sand, dish soap, glue, and water. Problem would be how to get it to dry quickly, and be put through a small nozzle. Yeah you would have to have one of those box sand blasters to clear the sand castings, but that would still be a lot quicker.

    • James Kiefer / about 9 years ago / 3

      I am working on a project where I needed to take a 3D print and cast it in aluminum. I created a silicone mold and cast the 3D print to wax and then used the wax copy to create a plaster lost wax mold which I then poured molten aluminum into.

      I am working on creating a blog post about it ... I will probably get it posted in the next month or so.

      • scharkalvin / about 9 years ago / 2

        That would actually work, and you don't need to make a silicone mold. Print the object you want to make a mold of in PLA and then encase it investment made of a mix of plaster and foundry sand (I don't know the right formula). Add sprues made of PLA or wax to provide the input trails for the casting metal. After the investment hardens place it upside down in a kiln to burn out the PLA and the wax. Something like 300C should do it. Now you have a 'Lost PLA' mold to pour your molten aluminum in. You'll have to make the original somewhat over sized to account for the shrinkage of the aluminum after casting. I think it's a few percent, google for the exact figure.

        • James Kiefer / about 9 years ago * / 1

          Yeah, that was my original plan but I quickly realized that creating the silicone mold would be good for a few reasons:

          • 3D printing is slow and printing my organic shape at high quality was taking 3-4 hours to complete, it takes me 20-30 minutes to make a wax copy using the silicone mold so it made it less stressful to do the lost casting knowing I could create another copy easily.

          • I really want a kiln but I don't have one yet. The only oven I have that would be good enough to burn out the PLA is my kitchen oven and I am far more comfortable evacuating some wax than PLA.

          • If I printed in ABS I could do an acetone bath and get smooth edges on the silicone mold. (Which I ended up doing)

          • If I failed at completing the aluminum cast I would be able to make a decent epoxy cast from the silicone in the worst case scenario.

          After doing the silicone mold I am happy I chose this method. The wax is far easier to clean up than the 3D print was so I was able to remove all evidence of it being a cast of a 3D print using just a cotton cloth and my fingers as 'sandpaper'. It also helped me understand how important it is to create your mold so that it will create pressure and force your molten medium into the cavities.

          My final mold that ended up working was a 50/50 ratio of plaster of paris and regular play sand. I had a large tapered sprue that built up pressure that went into a small gate and then a runner to the bottom of my cast with a riser on top.

          • scharkalvin / about 9 years ago * / 1

            You can use the same furnace that you melt the aluminum in as a kiln for melting out the PLA. I'm thinking of trying my own foundry work based on the books by Gingery, using his charcoal fired furnace.

            I do see your point about the silicone mold, but now you have two sources of shrinkage to account for when sizing the original!

            • James Kiefer / about 9 years ago / 1

              I used this design on youtube for my furnace. I still would not want to evacuate any sort of mold in this furnace haha.

              Double shrinkage is a good point and something I had not really thought about until you mentioned it. I definitely noticed some shrinkage with the aluminum pour but honestly did not notice too much with the wax. I suppose it helps greatly that my model was organic and only needed to "look" the right size.

              Good luck with your project!

              • scharkalvin / about 9 years ago / 1

                I made my furnace in a flower pot lined with concrete and perllite. The flower pot was stuffed into a large can that once held popcorn. The lid of the furnace was made in the lid of the can lined with a band of metal and has iron wire re-bar inside to help hold it together, again lined with the same concrete refractory. Haven't yet tried to fire it up, I have a old hair dryer for the blower. I made two crucibles from empty propane torch cylinders (held them under water and opened the valve with a nail to make sure they were empty!) The hole in the bottom of the pot will allow any aluminum that might spill to drain out the bottom of the furnace rather than into the blow hole. Furnace will be run over a pit of dry sand.

    • BBB / about 9 years ago / 1

      They are casting bismuth directly into 3d printed molds (http://makezine.com/projects/guide-to-3d-printing-2014/metal-casting-with-your-3d-printer/). I've been cold casting an epoxy/sand mixture into 3D molds. The molds are ABS which has been fumed with acetone vapor to smooth things out. By the way, I have found that vaseline makes a handy mold release for this. Just warm everything up to 150f and the vaseline melts and the casting comes right out.

  • StevetheClimber / about 9 years ago / 2

    A piston head

  • andy4us / about 9 years ago / 2

    fake dog poop

  • Member #368504 / about 9 years ago / 2

    Golfball

  • Lianna / about 9 years ago / 2

    The funny thing is that quite a few of the above things could actually be useful if needed, sensibly printed and used properly. My soldering iron stand is originally ABS (it grips around handle, not tip), I used 3D printed hex nut key for strange small size nuts (I needed it ASAP, not in two days), and I printed working bolt and nut, though it was as a trial for enclosure with twisted lid. PLA/ABS is quite tough in solid layers, I don't know if it would be enough for rollerblades, but I would not rule it out. Hammer describes many sizes and weights... I used PLA in somewhat elastic application (tweezers), so maybeslap bracelet could be possible with some clever, especially two-part, design.

    • scharkalvin / about 9 years ago / 1

      Remember the nut starter tool that came with every Heathkit? That could be 3d printed. (wonder it it's on thingiverse?)

  • DemolishManta / about 9 years ago / 2

    a cup

  • suitable1 / about 9 years ago / 2

    bench vise

  • ConnorGames / about 9 years ago / 1

    Rack ears

  • Member #673013 / about 9 years ago / 1

    A cooking pot.

  • DMacATTACK / about 9 years ago / 1

    an entire tshirt

  • Member #583789 / about 9 years ago / 1

    Scuba tank. Motorcycle helmet. Hip replacement. Dental crowns. Razor blades. String. Party balloons. Pinatas. Hard candy. Magnets. E.D. pills. Baby bottles. Diapers. Toilet paper.

  • Member #583789 / about 9 years ago / 1

    Parachute. Tires. Windshield. Pole vaulting pole. Football for the New England Patriots. Oil pipeline. Cruise ship.

  • Member #345198 / about 9 years ago / 1

    High heel shoes 👠👠

  • ludvikherrera / about 9 years ago / 1

    An eye patch, you can print different colors.

    • ludvikherrera / about 9 years ago / 2

      I actually love the sparkfun boxes where all the products are shipped. I keep them. It would be awesome to have a SparkFun 3D Printed Box.

    • ludvikherrera / about 9 years ago / 1

      Spark Glass (like Google Glass) or Spark Watch (Apple Watch) so you're always trendy on the cheap ;)

    • ludvikherrera / about 9 years ago / 1

      Gloves that look just like your hand, or cartoon like your favorite character, Mario, Mickey Mouse, Toshi, etc.

    • ludvikherrera / about 9 years ago / 1

      It's summer, sidewalk chalk holders.

    • ludvikherrera / about 9 years ago / 1

      Worthless plastic bitcoins!

    • ludvikherrera / about 9 years ago / 1

      Sparkfun logo pen/pencil top. An assortment of the sparkfun team members in a pencil top. Collect them all.

    • ludvikherrera / about 9 years ago / 1

      Bendy straws?

    • ludvikherrera / about 9 years ago / 1

      Icecream scoop, also multicolor.

  • Max_Phil / about 9 years ago / 1

    Kelly LeBrock

  • Max_Phil / about 9 years ago / 1

    Legos

  • Hackberry Jake / about 9 years ago / 1

    Invisibl-a-ble braces

  • EvilTwin / about 9 years ago / 1

    Important note on the limitations of 3d printing, the plastics involved are low melting point and sensitive to caustic chemicals, so anything you make that goes near food is problematic, since methods that would sanitize or sterilize other things made of plastic would melt 3d printed objects.

  • Skerpy_D / about 9 years ago / 1

    A development board.

  • PointyOintment / about 9 years ago * / 1

    Mains wiring. A Thermos. The bolts that hold the wheels on a car. Any household appliance (clothes washer/dryer, dishwasher, toaster…). A comb. The fences and obstacles for AVC, or the robot combat enclosure.

  • Member #684611 / about 9 years ago * / 1

    A toilet bowl with a yellow rim

  • Member #496759 / about 9 years ago / 1

    Diffraction grating.

  • Member #496759 / about 9 years ago / 1

    Welding goggles.

  • Llamas. / about 9 years ago / 1

    Oven thermostat holder.

  • Member #188794 / about 9 years ago / 1

    chainmail

  • Member #365431 / about 9 years ago / 1

    The Undead

  • jma89 / about 9 years ago / 1

    Deep fryer basket

  • Lion XL / about 9 years ago / 1

    Shotgun shells -- might be doable -- but I wouldn't.....

  • Member #375102 / about 9 years ago / 1

    Brake Pads Bicycle or Automotive

  • Member #684281 / about 9 years ago / 1

    Replacement blender or food processor blades. Clamps tire iron or tire jack

  • BeerCannon / about 9 years ago / 1

    a lawnmower blade

  • Yodaob1 / about 9 years ago / 1

    Muffin Tin

  • Yodaob1 / about 9 years ago / 1

    Grill Grate (roast some Dogs)

  • OrganicOyster / about 9 years ago / 1

    Fire crackers

  • OrganicOyster / about 9 years ago / 1

    LiPo storage box

  • Member #368504 / about 9 years ago / 1

    Reciprocating saw blade, tow hitch, angle grinder discs, steam whistle, garden trowel

  • OrganicOyster / about 9 years ago / 1

    Your boss finger prints

  • OrganicOyster / about 9 years ago / 1

    Hookah bowl

  • OrganicOyster / about 9 years ago / 1

    Adult toys

  • rdnetto / about 9 years ago / 1
    • a dice (balance issues, not to mention that everyone would assume it was biased anyway, because why else would you print a dice?)
    • an axe
    • a parrot (she's only resting)
    • a banana (for scale)
    • a screw
    • a nuclear reactor
  • Skimask / about 9 years ago / 1

    Lava lamp

  • Jack16 / about 9 years ago / 1

    Potholders, hot pad, stove grate, propane tank.

  • Member #143974 / about 9 years ago / 1

    Handcuffs or prison door

  • EvilTwin / about 9 years ago / 1

    "Rambo" knife.

  • EvilTwin / about 9 years ago / 1

    Tea! Earl Grey, Hot!

  • Jwd270 / about 9 years ago / 1

    A rocket

  • Butterwaffle / about 9 years ago / 1

    A solar collector (high pressure and temperature for twice the fun!)

  • Skimask / about 9 years ago / 1

    Prosthetic ear

  • Hackberry Jake / about 9 years ago / 1

    Portable air tank

  • Member #220272 / about 9 years ago / 1

    Lamp Shade (like the ones that used to clip on/over a bulb), especially for an incandescent or halogen bulb.

  • Member #500261 / about 9 years ago / 1

    Any sort of food utensil... Knives, forks, spoons, bowls even.

  • tcabeen / about 9 years ago / 1

    Tesla Coil

  • tcabeen / about 9 years ago / 1

    Toothpick

  • Hackberry Jake / about 9 years ago / 1

    Table saw blade (dont worry about sending it to me when you're done with it)

  • BeerCannon / about 9 years ago / 1

    an aqualung

  • Blacklab1 / about 9 years ago / 1

    RE: Dentures/Retainers --- they are already doing that. The COOL thing about this idea is when they now make the mold of your mouth, they can scan the mold (Which means you don't have to have a new mold of your mouth every time they want to do something- the old way destroyed the mold so you had to have a new one every time), then make the Dentures/Retainer/whatever. You lose your Dentures, retainer, whatever, they can make a new one without the hassle which means quick turn around.

  • An aerospike nozzle. Those things get crazy hot.

  • MiketheSheep / about 9 years ago / 1

    An Official SparkFun Ninja Star or, to fulfill the little Ralphie in my heart, a Red Ryder, carbine action, two-hundred shot range model air rifle.

  • Member #526348 / about 9 years ago / 1

    elevator wheel

  • Member #368504 / about 9 years ago / 1

    ninja flex toliet plunger (dont send this to me heh). Fingernail polish remover bottle

  • lug nuts for a car

  • Member #368504 / about 9 years ago / 1

    berings, axe head (or hatchet), arrow tips, circular saw blades, shoes cleats (actually that might work), ice pick, spade bit, door hinge, door key, wrenches, sockets

  • Koyaanisqatsi / about 9 years ago / 1

    Disc brake rotors, skillet, bullet shells, bicycle forks, compressor tank or fittings,.

  • Member #368504 / about 9 years ago / 1

    golfballs, lots of golf balls. With various filling percentages and of different materials... Hrm wood? stone? ninja flex?? eh? eh? oooo what about golf club heads?

  • Member #684041 / about 9 years ago / 1

    Bomb containment vessel!

  • Sembazuru / about 9 years ago / 1

    How about Carabiner. Or looking at the cover image for the last blog post, how about a heat-gun nozzle for SMT rework?

  • Member #368504 / about 9 years ago / 1

    Bastard file, can opener (prying or twisting), nails, dremel tool saw bit, lawn mower blade

  • Flux capacitor. Those things are more in the CNC wheelhouse.

  • Member #109708 / about 9 years ago / 1

    DIY Dentures

    I'm feeling a bit constrained by rule #3.

  • Sraf / about 9 years ago / 1

    Toaster oven

  • ME heat o nator / about 9 years ago / 1

    sandwich

  • cholq / about 9 years ago / 1

    a nail or a screw

  • Member #444314 / about 9 years ago / 1

    AK-47 or any other gun

  • nanogear / about 9 years ago / 1

    A HIGH CURRENT ELECTRICAL ISOLATOR

  • Member #107110 / about 9 years ago / 1

    Pie tin, razor blade, bicycle crank, bicycle gears, bicycle brake rotor, axe blade, hacksaw blade

  • A pacifier for my new daughter.

  • Member #284836 / about 9 years ago / 1

    socks, file (rasp)

  • ME heat o nator / about 9 years ago / 1

    candle

    • scharkalvin / about 9 years ago / 1

      Why not, if you print it in wax (and add the wick after the fact)?

  • Daniel Sims / about 9 years ago / 1

    -Stepping stand -Toothbrush handle -Shot glass

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