JB Weld Fixes Cracked Cylinder Heads

May 16, 2017 by 78 Comments

There are persistent rumors that the main ingredient in JB Weld is magic. This two-part epoxy that you would normally find on a shelf next to your basic 5-minute epoxy, Titebond, various cyanoacrylates, and Gorilla glue is somehow different. Stories of ‘some guy’ in the Yukon using JB Weld on a cracked engine block abound. These stories are of course met with skepticism.

Now, finally, we have evidence you can use JB Weld to fix an engine. [Project Farm] over on YouTube gave it the ultimate test: he took the cylinder head off a lawnmower, took a grinder to the head, and patched the hole with JB Weld. The head had good compression, and the engine actually ran for 20 minutes before the test was concluded.

If this were a test of a field repair, it would be a test of an extremely crappy field repair. [Project Farm] made no attempt to ensure the piston didn’t make contact with the blob of JB Weld, and in fact, there was some slight knocking from the piston tapping against a blob of epoxy. Still, this repair worked.

While this serves as proof of the feasibility of repairing an engine block with JB Weld, there is one ultimate test of JB Weld epoxy: build an engine out of it. For years, I’ve been casting my leftover JB Weld into a small square plastic container. In a few more years, I’ll have a block of JB Weld ‘stock’, large enough to machine the parts for a small (.049 cc) glow engine, like what you would find in ye olde tymie model planes and cars. Will it work? I have no idea, but now I can’t wait to find out.

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Hackaday Prize Entry: Electric Variable Pitch Props

April 3, 2017 by 39 Comments

Barring the smallest manned airplanes, most aircraft that are pulled around by a prop have variable pitch propellers. The reason for this is simple efficiency. Internal combustion engines are most efficient at a specific RPM, and instead of giving the engine more gas to speed up, pilots can simply change the pitch of a propeller. With a gas powered engine, the mechanics and design of variable pitch propellers are well understood and haven’t really changed much in decades. Adding variable pitch props to something pulled around by an electric motor is another matter entirely. That’s what [Peter McCloud] is building for his entry to the Hackaday Prize, and it’s going into the coolest project imaginable.

This project is designed for a previous Hackaday Prize entry, and the only 2014 Hackaday Prize entry that hasn’t killed anyone yet. Goliath is a quadcopter powered by a lawnmower engine, and while it will hover in [Peter]’s test rig, he’s not getting the lift he expected and the control system needs work. There are two possible solutions to the problem of controlling the decapatron: an ingenious application of gimballed grid fins, or variable pitch rotors. [Peter] doesn’t know if either solution will work, so he’s working on both solutions in parallel.

[Peter]’s variable pitch rotor system is basically an electronic prop mount that connects directly to the driven shafts on his gas-powered quadcopter. To get power to the electronics, [Peter] is mounting permanent magnets to the quad’s frame, pulling power from coils in the rotor hub, and rectifying it to DC to drive the servos and electronics. Control of the props will be done wirelessly through an ESP32 microcontroller.

Variable pitch props are the standard for everything from puddle jumpers to acrobatic RC helis. In the quadcopter world, variable pitch props are at best a footnote. The MIT ACL lab has done something like this, but perhaps the best comparison to what [Peter] is doing is the incredible Stingray 500 quad. Flite Test did a great overview of this quad (YouTube), and it’s extremely similar to a future version of the Goliath. A big motor (in the Stingray’s case, a brushless motor) powers all the props via a belt, and the pitch of the props is controlled by four servos. The maneuverability of these variable pitch quads is unbelievable, but since the Goliath is so big and has so much mass, it’s doubtful [Peter] will be doing flips and rolls with his quads.

You can check out a video of [Peter]’s build below.

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You Will Want To Build This Canoe

March 19, 2017 by 22 Comments

There is something about a wooden boat that should be facsinating to most makers, the craftsmanship and level of work that goes into creating a sea-, lake-, or river-worthy craft with smooth lines, from little more than thin pieces of wood. Master boatbuilders have apprenticeships that last years, and spend entire careers refining their art.

[Adam], also known as [A Guy Doing Stuff], is not a master boatbuilder. In his words, he’s just a guy with some basic woodworking knowledge, who builds canoes from cedar strips. But you wouldn’t know that he has no training as a boatbuilder from looking at his work, which you can do because he’s posted some beauthiful videos.

We see the creation of a skeleton to produce the basic shape of the boat, followed by the creation of prow and stern. Then there is a painstaking application of carefully shaped cedar strips to make the hull, and a single layer of glass fibre on either side. With the gel coat applied though you wouldn’t know the fibre was there. Finally we have the creation of the seats and interior fittings, followed by the canoe being paddled across a lake.

Few of us may ever make a canoe. But if we did, we’d want it to be one like this one.

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3D Printed Engine Chugs Away On Balloon Power

March 10, 2017 by 32 Comments

So often, 3D printer owners buy their machines with the promise of freeing themselves from the shackles of commercial manufactured items, and making all sorts of wonderful and useful things to improve their lives. Then they proceed to print a menagerie of good luck cats and toy elephants, that little tugboat, and a host of other pretty but ultimately useless items in garishly colored filament.

Perhaps this is an unfair assessment, but if you have the sneaking feeling that it might just describe you then could we point you at something that while it still has little use is at least interesting to play with. [Gzumwalt]’s single cylinder air engine is as its name suggests, a piston engine that runs on compressed air. You don’t need a shop compressor though, your lungs or an inflated balloon will suffice.

It’s a simple enough design, but it does incorporate two connecting rods, one of which drives a sliding valve. All the files are available for download, and there is a video we’ve placed below the break showing it chugging away nicely from a balloon. It might not be the most useful of engines and it may not bring you good luck, but it beats a plastic menagerie in the interest stakes.

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Another Kind Of Cloud: The Internet Of Farts

November 16, 2016 by 33 Comments

It’s taken as canon that girls mature faster than boys. In reality, what happens is that boys stop maturing at about age 12 while girls keep going. And nothing tickles the fancy of the ageless pre-teen boy trapped within all men more than a good fart joke. To wit, we present a geolocating fart tracker for your daily commute.

[Michel] is the hero this world needs, and although he seems to have somewhat of a preoccupation with hacks involving combustible gasses, his other non-methane related projects have graced our pages before, like this electrical meter snooper or an IoT lawn mower. The current effort, though, is a bit on the cheekier side.

The goal is to keep track of his emissions while driving, so with a PIC, an ESP8266, a GPS module, and a small LCD display and keyboard, he now has a way to log his rolling flatulence. When the urge overcomes him he simply presses a button, which logs his location and speed and allows him to make certain qualitative notes regarding the event. The data gets uploaded to the cloud every Friday, which apparently allows [Michel] to while away his weekends mapping his results.

It turns out that he mainly farts while heading south, and he’s worried about the implications both in terms of polar ice cap loss and how Santa is going to treat him next month. We’re thinking he’s got a lock on coal — or at least activated charcoal.

Our beef with this project is obvious – it relies on the honor system for input. We really need to see this reworked with an in-seat methane detector to keep [Michel] honest. Until then, stay young, [Michel].

Super-Sizing Leaf Collection; Hackers Doing Yardwork

November 13, 2016 by 33 Comments

For many parts of the world, the great raking has begun as deciduous trees in temperate zones drop their leaves. Of course not everyone can abide the simple yet laborious process of manual raking and so they look to technology. You can buy a handheld leaf vacuum, a pull-behind leaf sweeper, or a mower attachment that lifts leaves into hoppers. [Lou] has the latter, but it’s way too small for his taste so he super-sized his leaf collecting hardware.

The hard part of leaf collection has already been solved for [Lou]. The riding lawnmower lifts the leaves and propels them through an angled pipe into three hopper bags which we think total 9 bushels (roughly 80 gallons or 300 liters). That sounds like a lot, but anyone who has recently cleared leaves will attest that they will fill up in no time.

[Lou] builds a light-weigh 4-foot cube covered in deer netting to super-size his hopper to a whopping 51 bushels (475 gallons or 1800 liters)! His first attempt uses a pipe that falls too short to fill leaves to the top, but his final product adds longer ductwork and hits the mark perfectly.

Gardeners everywhere should be salivating right now. Leaf mulch is one of the best things you can put on your garden in the spring. Although [Lou] designed his hopper to be emptied by leaf-blower, adapting this to set the full hopper in an out-of-the-way space would help them breakdown over the winter — turning them into planter’s gold by springtime.

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Retrotechtacular: FAX As A Service In 1984

November 4, 2016 by 28 Comments

If you tell someone these days to send you something via FAX, you are likely to get a look similar to the one you’d get if you asked them to park your horse. But in 1984, FAX was a mysterious new technology (well, actually, it wasn’t, but it wasn’t yet common to most people).

fed-ex_zapFedEx–the people who got famous delivering packages overnight–made a bold move to seize a new market: Zapmail (not to be confused with the modern mass mailing service). The idea was simple (you can see a commercial for it in grainy VHS splendor below): Overnight is great, but sometimes you need something sent across the country now. A FedEx driver picks up your documents, carries them to a FedEx office. There the documents FAX to another FedEx office where another driver delivers the printed copy. The process took two hours to get a paper document from one side of the continent to another.

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