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Picture of Copper Cap Refrigerator Magnets
For when you need no fooling, it's on there frig magnets.

My mother's birthday was coming up and while I had a nice present for her, I needed a 'stocking stuffer'. Something small and useful. The last time I was over there we were cooking and had a comedy of errors as about half the magnets on the refrigerator fell off during the evening. Most of them where the thin, free type you get in the mail or as a promo item.

Thus the idea for the making of the ultra powerful, no messing around refrigerator magnets with major pull and serious height to ease the gripping was born.
 
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Step 1: Design Issues

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The key to this whole thing is the magnets. I had some powerful, Neodymium (aka rare earth) magnets laying around from an old project and thought to use those. These have a pull over 10 times the ones she was currently using.

These magnets are so powerful (the ones I'm using have about a 5 to 6 pound pull force), I was concerned about getting a grip on them and then, having the grip object develop a glue failure. As you can see from my notes, if the glue strength is less than the magnet pull, then you will have a magnet stuck to the refrigerator and a nice grippy thing in your hand. Even if the glue is really good stuff, it will still stress the glue joint every time you pull it off the frig. Also, I wanted a grippy thing that was a bit taller then you normally see - My folks are not getting any younger and having to pinch down with the tips of their fingers to pull it off would not be a good thing.

So the answer was simple - copper pipe end caps. Available wherever you get your local plumbing supplies. Since the magnets I already had where 1/2" in diameter, I needed to get 1/2" end caps. 1/2" end caps actually have an inner diameter of about 5/8" (to fit over the 1/" pipe that has a 1/16" thick wall) so there would be a little wiggle room but not too much.

Step 2: Materials needed

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First off, decide how many of these you want. The magnets usually comes in multiples of ten to twenty from the various online suppliers, but you can get the copper end caps one at a time from your local plumbing supplier. The magnets are useful to have around so more is not that bad a thing.

The magnets. This project is all about the magnets. I am using 1/2" diameter, 1/8" thick neodymium magnets. They are had to find locally, and thus we do that thing called online shopping. There are a good number of online stores that sell these magnets, but I like Ebay because it gives you multiple prices and options to compare before buying. I did a little digging on Ebay and as of this posting date, these are a couple of the Ebay stores with better deals for the magnets. Wherever you go to get the magnets, be sure to get the type that want to stack top to bottom, not the type that wants to go edge to edge.

Some number of 1/2" copper pipe end caps. I got mine at the local Lowes. You might want to hurry and get yours soon wherever you go for such things - the bums have raised the price $.07 in the last week. It used to be $0.36 each.

Finally, you need some flavor of glue, some copper cleaner and something clear to seal the copper to keep it shiny. I'm using 2 part epoxy for the glue because I left my hot glue gun on for over a week and killed it. Epoxy is vast overkill for this, we just need something to have the magnet not slip "down inside the copper end cap. A piece of doubled over scotch tape would work. I would have used hot glue if my gun was not dead.

The Tarn-X is to clean up the copper end caps so they are bright and shiny. Once it is bright and shiny and has a magnet in it, you want to seal the copper to keep it pretty. The first attempt I used the spray on gloss polyurethane and wasn't that happy with the result - it was kinda splotchy and grainy on the copper. I then used something I've heard about but haven't tried yet. Future floor wax is a very thin, clear gloss acrylic paint. It protects the surface from wear and tear and goes on smoothly. I've heard about this from the miniatures painting crowd and thought this would be an excellent chance to try it out.

Step 3: Putting it all together

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First off, take out the copper end caps and use whatever cleaner you have to make them sparkle. I like to do this step first before the gluing so I can try and get the inside of the end cap as much as possible.
Now that you have some shiny end caps, fire up the glue. I use a toothpick to smooth the glue out inside the end cap so it's an evenish layer before putting in the magnet.

Put the magnet in, push it around with the toothpick so it's flat on the bottom, then stick it down on something that it can grip. Not on the side like the frig because the glue might run and make the insides messier than they need to be. Having the magnet pull straight down will make sure it's in good contact with the glue. Now we wait for the glue to dry.

Once the glue is dried, it's time to seal the surface and keep the tarnish and oxidation away. Here I'm just painting on the Future Floor Wax. It went on smooth and easily.

Give your clear sealer time to dry (for the Future stuff, it's a half hour) and then you are done!

Thanks for getting this far in the instructable. You can visit my website at whamodyne.com for this and other projects I'm working on, as well as some puttering around and learning what works and what doesn't kind of stuff.
Vissy4 years ago
Great!

Improvement:
Just fit a magnet to the inner diameter of the copper endcap, and use it the other way around. You can fill up the cap with more magnets or glue.

I like magnets, so I just use bare magnets.
whamodyne (author) 8 years ago
Mr Slippy, Is that a solid copper slug, 10mm thick and 13mm in dia? I don't know if that would work. Using the end cap, the gap between the magnet and the frig is less than 2mm. Magnet strength goes down over distance, I would suspect it's a non-linear thing and thus, 10mm thick might be too much. I was also trying to do something with parts that folks can find at your general local store. Yeah, the magnets are not that normal but they have so many uses that getting more than you need for a project like this is not a bad thing.
Well, yeah, I was thinking of drilling out the slugs, putting the magnet in the open end. It wasn't a criticism, by any means....I'm known for suggesting completely unfeasible stuff a lot of the time ;-)
Those 10 mm x 13 mm copper slugs should be useful for something though.
Kaiven8 years ago
intresting
Cool instructable. You could save yourself having to buy copper caps by befriending somebody who makes copper busbars for large distribution boards. We punch 13mm dia holes in the 10mm thick copper bars to attach cables to...the copper nuggets that get punched out look like they'd be perfect for something like this. Hmmm....I should go get some strong magnets and do that very thing myself
I say bullet casings! also perfect for mom's birthday!
Oh yes, shotgun shells, or smaller diameter (but less grip)? L