DIY neodymium cleaning magnet

[nsamouroux]

I've been looking at cleaning magnets for use on my new tank (a large 5/8" acrylic display) and getting discouraged at the price tag of $300 for a Magnavore or similar product. After a bit of research and brainstorming, I may have come up with a great-looking, functional, and somewhat inexpensive DIY magnet cleaner. So far, the plan is to use two rare earth / neodymium magnets on each half of the cleaning tool. I just ordered 8 of these magnets (in case I want an extra magnet tool or goof something up :lol; they are expected to arrive this Friday (9/25). They are 1 3/8" diameter, 1/2" thick N42 magnets with a pull strength of 63 lbs each. I figure a pair of these would be plenty strong to hold through up to 3/4" acrylic (Neo magnets when paired exert 1.5x their individual pull strength so I'm looking at 94 lbs for each pair of magnets).

To hold the magnets, I didn't want to use wood / epoxy combinations or the like for fear of it degrading over time and screwing up my water. I decided to buy a couple of rectangular sample pieces of clear cast acrylic (may also use PVC or HDPE, but will start with acrylic) in 1.5" thickness. I will use a 1 3/8" forstner bit to drill two holes in each acrylic block, then insert the magnets into each half. I will then fill the holes with weld-on 16 (or the thinner stuff, depending on test runs) and then place a cylinder-shaped acrylic "plug" into the hole which should bond permanently via the weld-on and protect the magnet from saltwater (or from flying out at high speeds and breaking something expensive ). The end result will be a nice-looking 3" x 4" or so block of acrylic with cleaning pads (might buy the Magnavore replacement pad / tune-up kit to use on them, or the "magic eraser" pads). I think it'll look great, because you'll be able to see the magnets "floating" inside the block. I'll probably use black or smoke colored acrylic for the interior piece since it doesn't really need to be clear like the visible side will be.

I'll post updates as the materials come in!

 

[roscoe]

I've been looking at cleaning magnets for use on my new tank (a large 5/8" acrylic display) and getting discouraged at the price tag of $300 for a Magnavore or similar product. After a bit of research and brainstorming, I may have come up with a great-looking, functional, and somewhat inexpensive DIY magnet cleaner. So far, the plan is to use two rare earth / neodymium magnets on each half of the cleaning tool. I just ordered 8 of these magnets (in case I want an extra magnet tool or goof something up :lol; they are expected to arrive this Friday (9/25). They are 1 3/8" diameter, 1/2" thick N42 magnets with a pull strength of 63 lbs each. I figure a pair of these would be plenty strong to hold through up to 3/4" acrylic (Neo magnets when paired exert 1.5x their individual pull strength so I'm looking at 94 lbs for each pair of magnets).

To hold the magnets, I didn't want to use wood / epoxy combinations or the like for fear of it degrading over time and screwing up my water. I decided to buy a couple of rectangular sample pieces of clear cast acrylic (may also use PVC or HDPE, but will start with acrylic) in 1.5" thickness. I will use a 1 3/8" forstner bit to drill two holes in each acrylic block, then insert the magnets into each half. I will then fill the holes with weld-on 16 (or the thinner stuff, depending on test runs) and then place a cylinder-shaped acrylic "plug" into the hole which should bond permanently via the weld-on and protect the magnet from saltwater (or from flying out at high speeds and breaking something expensive ). The end result will be a nice-looking 3" x 4" or so block of acrylic with cleaning pads (might buy the Magnavore replacement pad / tune-up kit to use on them, or the "magic eraser" pads). I think it'll look great, because you'll be able to see the magnets "floating" inside the block. I'll probably use black or smoke colored acrylic for the interior piece since it doesn't really need to be clear like the visible side will be.

I'll post updates as the materials come in!

You should also look into making the wet side of the magnet float to the surface when they are apart. So that way you don't have to go tank diving to retreive the wet side.

 

[nsamouroux]

I thought about how to accomplish that, but I would have to hollow out and then cap / seal a BUNCH of air gaps (or hollow out the entire center of the thing), which would be more hassle than it's worth. With the strength of these magnets I very much doubt that they'll come loose at any point... I'm actually wondering if I'll even be able to pull apart something that uses four of these suckers :lol:

 

[roscoe]

I thought about how to accomplish that, but I would have to hollow out and then cap / seal a BUNCH of air gaps (or hollow out the entire center of the thing), which would be more hassle than it's worth. With the strength of these magnets I very much doubt that they'll come loose at any point... I'm actually wondering if I'll even be able to pull apart something that uses four of these suckers :lol:

OH OK I didn't think you was planning to keep it in the tank.

 

[nsamouroux]

Perhaps, depending on how well the pads / magic erasers hold up being left in the tank. I usually hide my magnet cleaners under an overflow box or something on the back panel inside the tank so it doesn't grow algae, but I might take this out after each use to keep it clean.

 

[returnofsid]

Keep in mind, with that many magnets, of those sizes, and with how strong this will end up being....going around corners could cause some problems. The magnet will have to release from one pane and snap to the other. This could cause possible breakage, or the heavy inner piece to drop to the bottom.

 

[nsamouroux]

My new tank doesn't have rounded corners like my 100g either The only way I could see to switch panels was to reach in and detatch it near the surface, place it on the inside of the next panel, then bring the dry side towards it so that it doesn't cause the wet portion to "jump" towards the panel. I will probably rig up some sort of handle for the exterior portion (like a brass knuckle shape? :lol to provide a better grip since this will probably be awfully hard to move / control with any finesse. Combined with these magic eraser pads, it should clean and polish the acrylic nicely even if coralline manages to grow with every-other-day cleanings. I let my 100g tank go a week or so before cleaning the panels and it is extremely difficult to clear off the coralling / green colored coralline-ish algae without scratching the heck out of it.

Any ideas how to make the wet side float? I don't know if it is possible to hollow it out enough while still holding the magnets securely, but perhaps I can put a bunch of holes in the back side of it and then cap it with a piece of clear sheet acrylic (like a swiss-cheese cleaning block!). I'll have to think about that some more...

 

[ciao]

I'm not sure if it's the same type of magnet, but if anybody has some old Hard Disk drives that are dead or no longer needed, you can pull some of the magnets used inside the disc housing as well. I remember my old roommate ripped apart an old drive he had and was playing around with the magnets inside it and BAM, they stuck together and he was never able to pull them apart again.

 

[nsamouroux]

You're exactly right, computer disk drives do use neodymium magnets, but I don't know what the pull strength on them is. I ordered 8 of the 1.375" diameter magnets w/ nickel coating (should look good through clear acrylic blocks!) that are 1/2" thick with a pull force of 63 lbs each. I'll have two magnets on each half of the cleaner tool, depending on just how strong these things are. They'll have about 1/4" of acrylic covering them, plus the 5/8" aquarium panel thickness, so I'm looking at 1 1/8" of space between the two pairs of magnets. I'll test with a 1.5 or 2" block of wood to make sure they hold securely throught that thickness.

 

[nsamouroux]

Yay, materials! I stopped by Tap Plastics on my lunch break today (damn, I love that store... They've got LOTS of useful stuff!) and picked up four blocks of 1.25" thick cell cast acrylic. Each block is 4" x 3" and clear. I also picked up a 6" length of 1.375" cast acrylic rod and a big tube of weld-on 16. On my way home, I raided Home Depot for a 1.375" forstner bit. Once the magnets arrive (Friday hopefully) I'll drill the 2 holes in each block, press-fit the magnets into the holes, then cut 1/4" discs out of the acrylic rod to use as a plug for the hole, and the weld-on 16 to encase the magnet and bond the plug in place. Looks like a plan! I still haven't decided if I want to go through the hassle of polishing the edges of the acrylic blocks... They were cut at Tap Plastics via table saw, but I can't decide if I want to leave it as-is for a somewhat better grip, or polish it to get a totally clear block (for the exterior portion at least). I guess I can always complete them, then wet-sand and use Novus polish / scratch remover at a later date... I think what I'll end up doing is routering down the corners / edges into a nice smoothe curve and then polish everything up. Should look pretty darn good, and MUCH less obtrusive than other large cleaning magnets if I do decide to leave it on the tank.

 

[returnofsid]

Yay!! Looks like the fun's beginning!!!

 

[nsamouroux]

I'm pretty sure (for now at least) that after I get them all put together and seal in the magnets that I'll flame polish the edges instead of screwing around with trying to sand / buff / hand polish them. Anyone got a spare torch? :badgrin:

 

[nsamouroux]

Well, I'm not the most patient person when I'm in the middle of a project, and I'm already itching to start putting these things together, but want to make sure I have the magnets in hand just in case something doesn't work the way I planned... To preserve my fragile sanity and to test things out, I grabbed a drill, the shiny new forstner bit, and a strip of 1/4" thick scrap extruded acrylic. It took about 2 minutes to punch a hole entirely through the piece (I didn't bother using water to cool it off, just went somewhat slow to avoid breaking / cracking), and the cast acrylic rod fits snugly into the hole. I might have to sand it down slightly once I drill into the blocks to fit the magnet (don't know if the magnets are 1.375 before coating with nickel, or if that includes the coating...), but everything should work out just fine Tomorrow I'll plug in the table saw and cut some 1/4" discs off of the acrylic rod to form the 8 plugs I'll need.

I was also looking at smaller diameter (1/2" and 3/4") acrylic rod pieces while picking up the other stuff at Tap Plastics to put together some sort of handle for the dry side to make moving it easier and more precise. I might get a pair of 6" length 3/4" diameter rods (if they have them in cast acrylic anyways) and use a heat gun to bend the last 1.5" on each side of the rod into 90* angles in order to form a handle that I can then bond to the back of the dry-side blocks. I have picked up enough materials so far to make two of these cleaning magnets, so hopefully one of them turns out the way I want it

 

[cali_reef]

You can try using these boxes. They should still float with a few magnets in them, after sealing them with acrylic or PVC solvent.

http://ElectronicsUSA.com/productsboxes.html

These things comes in different colors and material, PVC would be the best if you can find them. Stay away from acrylic and flimsy thin plastic boxes as they will brake the first time you drop them.

As for the no-float idea? My $100 magnet cleaner pops off about 5 out of 10 times I try to go around the corner of the tank.

You are a brave man for attempting to cut a 1/4" slice off acrylic rods on a table saw, please use goggles.

 

[nsamouroux]

I thought about using some of the small display boxes that Tap Plastics carries in their shop for the wet side, but figured it would be too lightweight. The main reason I'm not too worried about the floating aspect of the magnet is because if it somehow detatches and floats even with these magnets I run the risk of the wet side re-attracting to the dry side and slamming together against the panel. With 100 lbs of force per magnet pair (two pairs per cleaning tool) I would much rather play it safe and fish a magnet out of the bottom of the tank and wash out sand particles (or replace the pad entirely) than to risk having the two halves of the unit come slamming together with the aquarium (or body parts) in between...

Thanks for your concern. I always do wear goggles when running the table saw or wet tile saw. Haven't had any problems yet with flying chunks of sharpened doom (blade guards direct chips / particles downwards and out) but I've also never tried to cut this thickness of acrylic before and the blade guard will have to sit pretty high to allow it through. I've got a full face mask around here... somewhere... which is made from the same materials as the safety glasses that I use when playing with chainsaws or string trimmers and such, might not be a bad idea to find and use it. Thin cuts like this aren't really a problem, using the fence / guide on my table saw or tile saw (I've done it before with different materials and thin strips of laminate flooring), I just use a small wooden dowel or thin strip to push the "short end" past the blade while holding the longer side. That's why I bought a 6" rod when I'll only be using an inch or two of it I'm actually more skittish about the propane torch flame polishing, because I've seen WAY too many fireballs first-hand from propane and flame. Thankfully it has always happened to someone else, but I still never trust explosive materials (other than chili on nacho chips of course).

 

[artguy1]

Not sure what you plan on using the Weld On 16 for...but I would recommend using and experimenting with it prior to producing your final pieces. While Weld On 16 is quite viscous, the end results may not be what you expect. You might look into Weld on 4 or even 3.

What a great project you have going. I wanna keep up with your thread nsamouroux. Great thinking and creativity! Niiiiiiiiiice man!

 

[nsamouroux]

I was debating using weld-on 3, but I'm sure there will be inevitable gaps between the "plug" and the hole that I drill with the forstner bit and I've found the weld-on 16 to be MUCH better at sealing gaps between pieces. I use the 16 pretty often lately (most recently when I built the horizontal overflow for the new tank) and generally have good results with it, but I don't really know how it will look in this instance. I'm sure it'll work as intended to seal the gaps and protect the magnet from corrosion (and from flying out of the block at a high rate of speed...), but I don't know yet if I'll be able to make it look as clean as I would like. My entire goal with using the clear cell-cast acrylic was to make something that looks modern and aesthetic, while still being unobtrusive if I leave it in the tank on a side panel or something. Not much else is less obtrusive in water than clear acrylic, and I think it'll look cool to see the fancy nickel-coated magnets sliding along the viewing panels in the water. My goal is for the wet-side to be nearly invisible inside the tank aside from the magnets and the cleaning pad. I will have to remove it to keep algae from growing on it of course.

In the end, I hope to end up with something that looks good and functions as well or better (stronger?) than the commercial products. I just can't justify spending $300+ on a magnet with a scrubber pad when I can build something like this that (in my opinion) will look better for about $50 in materials. If I add up my time I'm sure I'll be close enough in cost to justify going out and buying a magnet, but I very much enjoy DIY projects

 

[nsamouroux]

Bah, just got the shipment tracking info from UPS, it looks like the originally stated 9/25 delivery date was a bit optimistic on the part of the magnet vendor. UPS has it scheduled to arrive 9/28. Good thing I'll be otherwise occupied with my new system build this weekend :lol:

 

[nsamouroux]

Hah! My magnets were delivered while I was at work These things are awesome! The UPS driver seems to have known what they were (no logo / company name on the box, must have found out the hard way :badgrin, because I found the box stuck to my door about 1/2 way up. Even through all the bubble wrap, cardboard, packing peanuts, etc, these things managed to stick to whatever steel is in my house's security door such that it took a good tug to remove them. I'd post pics, but I'm having way too much fun playing with these things!

 

[Slate]

Probably found it stuck to the inside of his truck heh.