Introduction: How to Make a "Bulletproof" Polycarbonate Longboard!
In an incredible epiphany, our team at SPHS decided to make a longboard deck out of polycarbonate!
Not only is the deck completely see-through, it is also bulletproof!
*But please, don't quote on us on that. We are not responsible for any liabilities involving injuries or death regarding the use of the deck as protection equipment.*
But anyway let's get to it!
Onto the materials!
Step 1: Materials
-3 axis or higher milling machine
-42"x12" sheet of polycarbonate with at least a 3/8" thickness (You may use other dimensions to suit your needs but I don't recommend that you use anything less than the stated thickness. For a stiffer board, get a greater thickness.)
-MasterCam Program (we used the X5 edition)
-1/4" flat endmill
-1/8" flat endmill
-Sandpaper or sand belt machine
-Griptape
-Common sense
Step 2: Design
For our design, we first sketched it on paper.
We chose a simple shape, almost in the shape of a bullet, with grooves in the middle of the board on both sides.
After the sketch, we transferred the drawing to MasterCam.
We attached the board file as a dwg so please feel free to use it as you wish.
*We didn't want to sketch anything too difficult, otherwise we wouldn't be able to redraw it in MasterCam. But if it is within your level, by all means go ahead and get as intricate as you want.*
Attachments
Step 3: Milling
Before we milled out the board, we did some test runs to see how the polycarbonate would mill.
At first, we cut it straight through but that was a disaster but we ended up using depth cuts for the milling.
For the settings, we used a medium cut speed and a high spindle speed.
*Please experiment with the settings as various thicknesses will alter how the material will cut*
Step 4: Final Product
Take the board to sandpaper to smooth out the edges and apply griptape however needed.
The board turned out VERY flexible but can still be ridden. We attached a video to show how flexible the board is. The rider is about 150 pounds.
Take note that this is more of a novelty than something for actual riding. You can still ride the board but nothing too intense like downhill bombing can be done. This board is more for a wow factor.
That's all and thanks for following this tutorial!
Attachments
Be the First to Share
Recommendations
For the Home Contest
Make It Bridge
Game Design: Student Design Challenge
36 Comments
1 year ago on Introduction
That nose looks dangerous.
BTW, the challenge with polycarbonate is cracking outward from the holes.
Heating it just above the melting point (tiny nozzle on a heat gun) helps.
5 years ago
I did a ballistics test on polycarbonate some time ago. 3/8" of the type sold for windows will barely stop a 22 LR, I started with one 3/32" thick piece, went though without leaving a hole, but a black spot from the lead bullet. 4 pieces stopped it in a polycarbonate bubble, protruding about the length of the bullet. On the other hand there was a shop that would bullet proof your car, had a 1 inch thick sample with a 7.62mm bullet that had gone only half way through. Not all polycarbonate is the same.
6 years ago
you need to make a curve mold, heat the plastic, and set it in the mold. the curve will help give it strength. im gonna make my own and will try to post it on here.
8 years ago on Introduction
would 12" x 48" - Clear Acrylic Plexiglass Sheet - 3/8'' Thick Cast work instead?
8 years ago
Actually a bullet would go straight through this. attatch a layer of acryllic to one or both sides (depending if you one one or two way bulletproofing). the acryllic will get hit by the bullet and get compressed between the bullet and polycarbonate. As acrylic compresses it gets harder and harder, flattening the bullet and spreading the force out for the polycarbonate to absorb without penetration.
9 years ago
I designed a board in inventor 2014 and set the material to polycarb after analyzing a stress test of a flat board I bent the part upwards then re did the test the result was a board that sat about level with the trucks. I know from my work with lexan that it bends fairly well. also using three sheets of 1/8 lexan seems to make it stronger. hope these suggestions help. happy making.
9 years ago on Introduction
In the name of safety, I'd round that spear point off the front for when you inevitably wipe out and send the board spiraling through the air at a high rate of speed and into you or someone else...
Reply 9 years ago on Introduction
We actually kept the pointy spear of death for laughs. The board is definitely not fit for street use and as said before, is more of a novelty.
Reply 9 years ago on Introduction
Glad to hear that...ouch!
9 years ago on Introduction
This is cool, but could you post your video to YouTube or Vimeo, then embed it here, so that it is a lot easier to watch?
Reply 9 years ago on Introduction
We would, but our high school does not allow youtube or vimeo.
Reply 9 years ago on Introduction
You could do that bit from home...
9 years ago on Introduction
You should give fiberglass a go on that :3 would look bloody sick with lights :D
9 years ago
What if you made one with layers of carbon fiber, poly carbonate, then carbon fiber? Would that stiffen it up?
Reply 9 years ago on Introduction
It would definitely stiffen it up but the reason we chose polycarb was for the transparency
9 years ago on Introduction
Awesome board!
Reply 9 years ago on Introduction
Thank you sir
9 years ago on Introduction
i like the extra pointy looking tip of death on the front
Reply 9 years ago on Introduction
We do too. The design was to imitate a dagger. Works pretty well haha
9 years ago on Step 4
Suggestions: A polycarb stiffener from truck to truck bolt patterns would make a stiffer board without adding dimension or much weight. For a lower tech entry approach, a medium duty bandsaw with a fine tooth blade will cut polycarb just fine ,so really the need would be to print the design, tape to stock and cut along line. The drill pattern for the trucks is not a blind hole so hole pattern layout isn't a CNC necessity. The watchword with polycarb is to minimize stress risers, so finish sanding is very important since the piece with be under dynamic flex load. A rattail file is your friend for those holes ;). Clear wheels or lighted bling wheels would flash this up too, a bit of cool neon wire added would also up the wow factor, perhaps added along said stiffener. Cool project, will add to builder class. Thanks for posting.