Homebrew Tire Inflator Pushes The Limits Of PVC Construction

March 22, 2023 by Dan Maloney 23 Comments

Let’s just clear something up right from the start with this one: there’s literally no reason to build your own tire inflator from scratch, especially when you can buy a perfectly serviceable one for not a lot of money. But that’s missing the point of this build entirely, and thinking that way risks passing up yet another fascinating build from PVC virtuoso [Vang Hà], which would be a shame

The chances are most of you will recall [Vang Hà]’s super-detailed working PVC model excavator, and while we’re tempted to say this simple air pump is a step toward more practical PVC builds, the fact remains that the excavator was a working model with a completely homebrew hydraulic system. As usual, PVC is the favored material, with sheet stock harvested from sections of flattened pipe. Only the simplest of tools are used, with a hand drill standing in for a lathe to make such precision components as the compressor piston. There are some great ideas here, like using Schrader tire valves as the intake and exhaust valves on the pump cylinder. And that’s not to mention the assembly tips, like making a hermetic seal between the metal valves and the PVC manifold by reaming out a hole with a heated drill bit.

We’re not sure how much abuse a plastic compressor like this will stand up to, but then again, we’ve seen some commercially available tire inflators with far, far less robust internals than this one.

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Fish Tank Dosing Pump Built Using Pi Pico

March 17, 2023 by Lewin Day 5 Comments

When you’re maintaining a fish tank, it’s actually quite important to get all your basic chemistry right. Mismanage things, and you’ll kill all the helpful bacteria in the tank, or kill your fish when things get too alkaline or too acidic. To help him get things just right, [yojoebosolo] built a custom dosing pump to maintain his fishtank.

The pumps themselves are small peristaltic pumps sourced from AliExpress. They can be had for under $10 if you look hard enough. Two of these are assembled into a PLA housing. Meanwhile, the brains of the operation is a Raspberry Pi Pico. It’s charged with running the pumps to a regular schedule, ensuring that just the right amount of chemicals are delivered when they are needed. It delivers 2 mL of Kalkwasser solution into [yojoebosolo’s] reef tank every ten minutes. The pumps are switched on and off with a simple 5V relay.

If you’ve got a delicate and complex fish tank that demands only the best, building your own dosing pump may be the way to go. Off-the-shelf versions can be expensive, after all, so sometimes it makes sense to roll your own. Video after the break.

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3D-Printed Lobe Pump Shifts Water Well

June 10, 2022 by Lewin Day 11 Comments

Lobe pumps are perhaps most popularly known for their use in Rootes-type superchargers, but they can pump water, too. [Let’s Print] demonstrates this ably with a 3D-printed design that can pump with the best of them.

The design uses two figure-eight shaped counter-rotating rotors, or lobes. As the rotors turn, they trap fluid between the rotor and the housing, forcing it towards the outlet. It’s a positive-displacement design, meaning it traps a fixed volume of fluid in each rotation, moving it from inlet to outlet.

The design requires proper timing of the two rotating lobes in order to ensure they maintain the closed volume and don’t impact each other. This is achieved with a pair of timing gears on the back of the pump. The housing, lobes, and gears are all 3D-printed, making this a build that anyone can replicate at home with their own printer.

ABS was used for the rotors for its better handling of friction without melting as easily. However, resin-printed lobes were also employed for their higher tolerances, too, with both designs working acceptably in practice.

The pump still needs more improvement; the hope is to reduce the leaks out of the rear of the pump. [Let’s Print] also intends to add a motor to the pump itself rather than using a power drill to run the device. It’s great to see these 3D-printed pump builds continuing in earnest. Video after the break.

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Stout Peristaltic Pump Fabricated From Scratch

January 12, 2022 by Lewin Day 18 Comments

The peristaltic pump is perhaps most well known for its ability to pump fluids without the pump mechanism coming into contact with the working fluid. This is key for food-safe applications and other situations where a pump could contaminate the fluid. [Maciej Nowak] has built a great example of such a pump, crafted out of aluminium from scratch.

The build video covers the machining process in detail, showing how the aluminium body was fabricated on the lathe before installing bearings and a silicone hose. The pump shaft was then fabricated, along with a set of brass rollers to press along the tube, creating the pumping action. The rollers were also lubricated in order to reduce friction on the tubing. Powering the pump is a small DC motor, sending drive via a small toothed belt, giving the finished build quite an industrial look.

We’re used to seeing plenty of 3D-printed pumps about the place. This build, while it requires a fully-equipped machine shop, is much tougher than anything plastic, and you could easily use it to break a window in an emergency too, an obscure feature nevertheless requested by some discerning pump customers.

[Maciej] shows off the build by pumping some green liquid, noting the peristaltic design requires no priming which makes operation much easier. It’s also bidirectional, and can be run very slowly if required.

Overall, it’s a build that shows off the benefits of working in metal as well as the great features of the peristaltic pump design. Video after the break.

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An Oil Diffusion Vacuum Pump From Thrift Store Junk

January 12, 2022 by Dan Maloney 13 Comments

It seems like creating a vacuum should be a pretty easy job, but it turns out that sucking all the air out of something is harder than it seems. A cheap vacuum pump will get you part of the way there, but to really pull a hard vacuum, you need an oil diffusion pump that costs multiple tens of thousands of dollars.

Or, you need a bunch of thrift store junk, a TIG welder, and a can of WD-40. At least that’s what [Lucas] put into his homebrew oil diffusion pump. The idea of such a contraption is to vaporize oil in a chamber such that the oil droplets entrain any remaining gas molecules toward an exhaust port. His low-budget realization of this principle involved a lot of thrift store stainless steel cookware, welded together with varying degrees of success, with liberal applications of epoxy to seal up any leaks. And an electric smores cooker for the heating element, which was a nice touch. The low-budget approach extended even to the oil for the pump; rather than shelling out for expensive specialty oil, [Lucas] distilled some from a WD-40 silicone spray lubricant.

The video below details all the travails [Lucas] encountered along the way, plus the testing process. The results were at least encouraging — the diffusion pump was pulling vacuum far in excess of what the roughing pump was capable of. He clearly still has some work to do, but getting as far as he did with the scrap heap of parts he cobbled together is pretty impressive.

[Lucas]’ goal with all this? A fusion reactor. No, not that kind. This kind. Continue reading “An Oil Diffusion Vacuum Pump From Thrift Store Junk” →

Power Your Home With A Water Battery

October 8, 2021 by Matthew Carlson 69 Comments

I’ve stated it before on Hackaday but one of the most interesting engineering challenges posed to me this year was “how could you store enough energy to power a decent portion of a home for several hours without using batteries, all while staying within the size of a typical suburban plot?” [Quint Builds] attempts something up that alley by using solar power to pump water up onto his roof and later releasing it for power generation. (Video, embedded below.)

Earlier [Quint] had built a water collecting system using his gutters and a bell siphon but wasn’t satisfied with the overall power output. Using the turbine he had created for that system, he put a 55-gallon drum on top of his roof with the help of some supporting structures. We’d like to advise the public to consult a professional before adding a large heavy weight on top of your roof, but [Quint] forges ahead after studying his trusses and determining it to be a risk he is willing to take. A solar panel runs a small pump that pumps water from a reservoir up to the top of the roof when the sun shines with a float switch in the roof barrel stopping the motor once it’s full. A valve at the bottom allows water to spin the turbine and fill back into the bottom reservoir, forming a closed loop. There were a few snags along the way with prototype circuits not being fully contacted and the motor needing water cooling, an issue fixed by a custom CNC’d heat sink. The fixes for the various issues are almost as entertaining to see as the actual system itself.

It’s incredible to see lights come on powered by water alone but also sobering to realize just how much water you’d need to power a typical home. Perhaps if [Quint] upgrades, he can swap out the small motor for a larger 3D printed water pump.

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You Can Put Toothpaste In The Tube (With Effort)

July 5, 2021 by Bryan Cockfield 20 Comments

Old wives’ tales, folk knowledge, common sayings, and even cliches and idioms are often taken as givens since they form an often unnoticed part of our vocabulary and culture. There’s so many examples that it’s possible to fill a 17-season TV show busting potential myths like these, and even then there are some that slipped by. For example, the saying “you can’t put toothpaste back in the tube” which, as it turns out, is not as impossible as we might be led to believe.

This video is the product of [Tyler Bell] who has taken this idiom on as a challenge. To figure out if it was possible he first got to work building a vacuum chamber, which turned out to be a little easier than he thought it would be. After cutting a piece of polycarbonate tube and sanding it down, all that was needed were some rubber gaskets and fittings for the vacuum pump.

From there, the theory was to put an empty toothpaste tube into the vacuum chamber, pump all of the air out, and let atmospheric pressure “push” the toothpaste back into the tube. During [Tyler]’s first run he thought that it had worked successfully but it turned out that he had just inflated the empty toothpaste tube like a balloon. Further iterations were able to return some of the toothpaste to the tube, but each time some air would eventually work its way into the toothpaste which would immediately fill the remaining space in the tube with air rather than toothpaste.

While not completely successful, he was able to get some toothpaste back into the tube with a relatively small bill of materials. It’s not likely that this experiment will result in a change of this particular idiomatic expression, but it was interesting to put it to the test nonetheless. For other instances of toothpaste and its relationship to tubes, both inside and out, be sure to check out this recent piece on various methods of toothpaste storage.

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