MOOP: DIY mobile nail/screw/metal pickup from recycled parts

[Canoe]

http://blog.makezine.com/archive/2011/1 ... abber.html
recycled hard drive magnets on bottom of 2x4 between two wheels

powerful magnets: expensive
recycled hard drive magnets: cheap or free

[Canoe]

magneticsweeper.jpg

[ygmir]

nice tool. good recycling.
Thanks for the pic.

[BBadger]

When rare earth metals are exposed to the air they corrode. I would suggest covering up the rare earth magnets with a protective covering, or putting them face-down into the wood rather than exposed upwards. They're strong enough to make metal objects fly at them with great force which can cause them to shatter, or at least damage the protective nickel plating. Even the force exerted on metal objects can cause the coating to become damaged over time.

[Canoe]

When rare earth metals are exposed to the air they corrode. I would suggest covering up the rare earth magnets with a protective covering, or putting them face-down into the wood rather than exposed upwards. They're strong enough to make metal objects fly at them with great force which can cause them to shatter, or at least damage the protective nickel plating. Even the force exerted on metal objects can cause the coating to become damaged over time.

Would counter-sinking the magnets into the wood and keeping the metal backing screwed on top of the wood be sufficient to handle the impact of metal MOOP?

[Foxfur]

Fiberglass lay-up resin is amazing and cheap as compared to regular two part epoxy. I use it for lotsa things. Lately I've used in for potting sensitive electronic projects to protect against moisture. Just be sure the circuit is the way you want it forever...

I was thinking of an improvement to the DIY mag pickerupper. Perhaps using a section of aluminum or plastic rain gutter with the magnets attached to a 1x2 with a couple of carriage bolts thru the central 2x4 and bolted thru another piece of 1x2 on top of all with a shed type handle on it. It would facilitate instant release of the magged stuff.

I used one @ the Frenchie Boy burn to pick up all the nails fron the effigy and the remains of the five couches that Bobnoxious set on fire. It was purchased by Oneeye @ harbor freight for ~$22.

[Canoe]

Hmm...
HF magnetic sweeper:
17" mini $15,
22" with release $30,
30" with release $35.

[BBadger]

When rare earth metals are exposed to the air they corrode. I would suggest covering up the rare earth magnets with a protective covering, or putting them face-down into the wood rather than exposed upwards. They're strong enough to make metal objects fly at them with great force which can cause them to shatter, or at least damage the protective nickel plating. Even the force exerted on metal objects can cause the coating to become damaged over time.

Would counter-sinking the magnets into the wood and keeping the metal backing screwed on top of the wood be sufficient to handle the impact of metal MOOP?

I think so, especially if the metal covering is also pressed against the wood. Still, the shockwave from the impact might be enough to affect the magnets because the metal is relatively thin. I've had those darn things crack from stress, and the surface bubble somewhat.

You could dampen it with other materials like that rubber goop that you put over tool handles, or the resin Foxfur suggested. Having a coating is also nice when you have a lot of other shit around, like rust, that can seep in the cracks and get on the actual magnet. etc. I like that idea of a release, as pulling that shit from the magnets can be annoying if it's small stuff. Maybe one of those mops with the built-in wringer can be used? Having retraction and good protection could also allow you to use even larger, more powerful magnets. Just make sure that when you de-retract your magnet that it doesn't "clack" together with the surface you're using as the guard.

[Canoe]

O.K.
Here's a way to unload with no fine debris held to magnets.

* Magnets are mounted to a wooden blade that is on a rod inside of an Aluminum tube. Aluminum seems to be what the commercial sweepers are using; possibly for DIY and cost, thin PVC could be used.
* The center rod projects out of the sealed end of the Al tube so a lever (not shown) can be attached to the rod to rotate it for unloading collected metal.
* When the lever is turned such that the internal blade with the row of magnet assemblies is rotated counter-clockwise, the collected metal is slid along the outside of the tube, up and over the top of the tube, and as the magnets pass by the external ramp, the collected metal is left behind, is no longer held by the magnets, and the collected metal falls down the ramp into the collection bin.
* As the collected metal will wear on the tube as it is slide up and over the tube, Al may be an expensive replacement. If PVC tube is thin enough to allow the magnets inside to be close enough to the ground to do the collection job, PVC could be a much more economical material to use.

* An alternate that would be simpler to build and would eliminate the collected metal from wearing on the tube as it slide up and over, would be to have the internal blade fixed in place within the tube, and then rotate the tube itself. As the position on the tube where the magnets and the collected metal encounter the ramp, most of the collected metal would be swept from the tube and would fall into the collection bin. Except that fine metal particles would likely NOT be swept off and could accumulate and have to be manually cleaned. No absolute release easily obtainable.

[BBadger]

Won't you need to have magnets along the entire rim of that tube? Otherwise it'll just fall off, or cling to the location of the magnet despite the surface moving. You might be able to attach a cam to the inside of the tube that'll retract the magnet at the edge so things fall off.

One problem will be that unless those wheels are really heavy and grippy, the magnets on the spinning wheel will be too hard to spin. It's like how hard it is to use one of those manual push lawnmowers if the wheels can't turn easily or the blade doesn't chop easily. It'll be even harder if you're trying to force those metal objects off the wheel and into the bin, as they'll catch and also want to hold onto the magnet.

[Canoe]

No. The tube is fixed and doesn't rotate. The wood blade with magnets all down it's "blade" stays in the bottom position under collection operation, with moop collecting all along the bottom only. To release what it's picked up, the blade inside is then rotated counter-clockwise (tube remains fixed in place), dragging the collected metal up and over the outside of the tube (also the source of the outside of the tube wearing). To avoid having a cam (and a movement beyond simply rotation), as the internal blade continues past the top of the ramp (which is fixed to the fixed tube), the moop cannot continue following the magnet as the ramp blocks it, and the magnet becomes too distant to hold the moop, and the moop falls down the ramp into the collection bin. The blade continues to the bottom position, and collection can begin again.

The alternate way has the internal blade fixed in reference to the tube (easier construction, less wear), and the resulting single assembly does not rotate during collecting. Both rotate for release (they're one structure) with the ramp in place but not fixed to the tube, hence the gap between ramp and tube means that not all of the moop will be released into the collection bin, and some moop may even jam between the ramp and tube.

In both, the tube is support up off of the ground by wheels, not shown in the diagram.

A series of blades could be constructed inside and collect and release as it moves along, but cost & weight go up, as does the force to push it along while rotating, and it requires an unattached ramp, with it's some retained moop and jam potential.