PVC

107 Articles

The Potowitzer: A Rapid Fire Potato Cannon

October 31, 2016 by 38 Comments

If you’ve ever fired a potato cannon, you’ll know that they are a raucous good time, but are somewhat clumsy to reload after each shot. Seeing an opportunity to improve on the design and minimize the delay between launches, [Danger First] have concocted a fast reloading potato cannon — or should I say — Potowitzer.

The key here is that they’ve gone through the extra effort of designing and building honest-to-goodness artillery rounds for their Potowitzer’s manual breech-loading mechanism. Foregoing the inconsistency of potatoes, they’ve 3D printed a bevy of bullets and sealed them with propane gas into PVC pipe cartridges. Metal contacts around the base to carry current from a BBQ lighter to the inside of the cartridge to ignite the propellant. Seeing it fire at about 18 rounds per minute is something special.

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$12 Quadcopter Frame From PVC Pipe

October 4, 2016 by 24 Comments

Flying ready-made quadcopters is fun. Eventually, though, most hackers get the urge to build their own. One of the most challenging parts is building a robust airframe. [Thomas Jarrett] has an interesting approach: he uses schedule 21 PVC pipe to build a sturdy airframe that is inexpensive and can house the craft’s electronics to boot. You can see a video of the sizeable aircraft, below.

The 1″ pipe is lightweight but sturdy and big enough to hold some circuitry. The rest is secured with Lexan. [Thomas] used off the shelf avionics, but it is obvious you could use the frame with your own choice of flight systems easily.

Perhaps the trickiest part is flattening the PVC for the motor mounts over a stove. The landing gear are also PVC, and formed in boiling water. Just be careful since hot PVC can give off nasty fumes (we aren’t experts on that, but it makes sense that it would be; you can watch a video about safety when heating PVC pipe). The total cost, including some prototyping parts, was under $300.

We’ve talked about building up drones in the past. If you don’t like PVC, you could always try old motherboards.

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Cheap And Effective Dune Buggy Wheel Chair

July 6, 2016 by 15 Comments

[masterfoo]’s mother-in-law suffers from a bad hip which would have sidelined her participation in the Fourth of July festivities. As a testament to the power of family and ingenuity, [masterfoo] built her a beach-capable wheel chair to give her some off-roading capability.

The frame is built out of 1.5″ PVC piping and the tires are 20×8-8″ inner tubes for ride-on lawnmowers. The lawnmower  wheel inner tubes were cost-effective and fit the purpose, saving the need for the more expensive purpose-built-for-the-beach Wheeleez tires. They also have a fluid inside that plugs small punctures which will come in handy against he beach’s small cacti and other flora. This video was their guide for the foam insulation and plywood wheel assembly, also employing the handy man’s secret weapon to protect the tube from the rim’s plywood edge. Check it out in action!

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3D Printing Compressed Air Tanks

June 2, 2016 by 107 Comments

Using PVC pipe as a pressure vessel for compressed air can be a fun and enjoyable hobby. It’s safe, too: while there are are reports of PVC pipe being the cause of accidents, these accidents include a black powder potato gun[1], and welding too close to a PVC pipe containing compressed air[2]. Compressed air stored in a PVC pipe is never a proximal cause in any accident, and the OSHA’s Fatality and Catastrophe Investigation Summaries bear this out; there was no industrial or occupational accident recorded in these summaries where a pressure vessel made out of PVC was the cause of any injury or death[3].

Although PVC pipe can be a perfectly safe, effective, and cheap pressure vessel for hobby applications, it’s not always the best choice. A group of students in Renens, Switzerland are building autonomous robots for the Eurobot competition, and this year’s robot uses pneumatics. That means compressed air, and that means a pressure vessel. Since just about everything else on this robot is 3D printed, they asked the obvious question. Is it possible to 3D print a tank for compressed air?

The tank for this robot would only be used up to about 4 bar (400kPa), and after a few quick calculations, the team discovered the wall thickness – even in a pressure vessel with corners – would be pretty low. The first prototype, a 40mm cube with 20% infill and a hole drilled in the side, held 6.5 bar (650kPa) for an hour. This success didn’t last, though: he second prototype, a 65x40x80mm rectangular prism printed without as much infill, exploded at 5.5bar (550kPa).

The third time’s the charm, and with filleted ribs inside the tank, the third prototype was able to hold pressure up to 6.5 bar. Of course no 3D print is perfect, and the third prototype did leak, but a bit of acrylic spray paint applied to the outer surfaces held the air in.

While it’s not as fun, easy, cheap, rewarding, or safe as using PVC pipe as a pressure vessel, the team did manage to build a 3D printed pressure vessel with a custom shape. You can’t do that very easily with round pipe. And 3D printing opens up all manner of internal structure to experiment with. We’d like to see this developed even further!

Sources: [1], [2], [3]

Feeding The Cat, Reinventing The Wheel

June 2, 2016 by 32 Comments

There are few projects that we see as many iterations of as the pet feeder or the plant waterer. (What is it with you people? Are you all as forgetful as we are?) Still, the fun is in the details of the implementation. Or at least that’s the case with [Emmaanuel]’s cat feeder.

The writeup is split into three parts: the worm-drive, the electronics, and the housing (here in English: worm, electronics, housing). And of course, there’s a video inlined below.

The auger and motor housing make great use of PVC pipe and 3D printing, and the dispenser unit looks quite professional. There’s not all that much to say about the electronics — an Arduino clone, an LCD, and a cheap gear motor do just about what you’d expect.

The CNC’ed case with spring-fit tabs steals the show, however. It’s made out of MDF, which doesn’t take well to screwing or glueing. With carefully routed pins and tabs that have a little spring in them, [Emmaanuel] was able to take the pieces off the mill table and just snap them together. Awesome.

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Feed The Fun With A Semi-automatic Cheesy Poof Rifle

May 23, 2016 by 18 Comments

At Hackaday we think that hackers have the power to make the world a better place with their builds. This air-powered cheesy-poof rifle is not one of those builds, unless making the world a little more fun and slightly messier makes it a better place.

The principle of [NightHawkInLight]’s design is simple – an electric leaf blower provides the power, and a big vat o’ poofs provides the ammo. Getting the two together and providing a barrel is a matter of some simple plumbing with 1″ PVC pipe and fittings. But wait – lest you think this hack, like the ammo, is just a delicious bit of fluff, there’s something to be learned about fluid dynamics here. With a plain tee fitting, the leaf blower would only pressurize the magazine, making it difficult to chamber a round. But by adding a small restriction to the incoming air flow, the Venturi effect actually sucks ammo into the chamber and down the barrel, to the delight of hungry wildlife for yards around. Science!

There’s plenty of room for improvement to the design – something along the lines of this gas-powered, tube-fed snowball gun would be keen. As it stands, the cheesy-poof gun seems like good, unclean fun.

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A Structural PVC Cyr Wheel

December 7, 2015 by 35 Comments

PVC is a great building material that can be used for everything from yurts and geodesic domes to pressure vessels. One thing we haven’t seen a lot of is bending PVC pipe. [Lou] wanted to build a Cyr wheel for his daughter, and instead of shelling out five hundred big ones for an aluminum version, he build one out of PVC using techniques usually reserved for woodworking.

A Cyr Wheel is usually a large aluminum hoop built for acrobatic performances. These performances are pretty impressive and look like a lot of fun, but the wheels themselves are rather expensive. Figuring PVC was a good enough solution, [Lou] built his own Cyr wheel for $50 in materials.

The build started off by laying out a jig on the floor. Two sheets of plywood were laid out, a radius for the wheel traced, and a bunch of blocks were glued to the perimeter of this mold. With the mold in place, a few pieces of PVC were flexed into position, clamped, heated with a hair dryer to relieve stress, and glued to a second course of PVC.

The process [Lou] used to build his Cyr wheel isn’t that different from extremely common woodworking techniques. In fact, it wouldn’t be unreasonable for [Lou] to build a wooden Cyr wheel with the same jig. We’re wondering how well this project will stand up to abuse, so if you have any insight to the uses of structural PVC drop a note in the comments.