Magnet advice

December 21, 2006

What's a good size earth magnet to use in stashing caches? I remember from high school that these things are pretty dang powerful and I don't want to buy them too big such that they perma-stick to the metal host.

Jay W

505/287 Dakota

20.7k · December 21, 2006

It depends on the size of the container you are planning on using.

Edited December 21, 2006 by sbell111

1.1k · December 21, 2006

The craft department of your local Wal-Mart should have some dime or quarter size magnets that would be fine for film can caches.

3.3k · December 21, 2006

You can always start here: http://www.leevalley.com/wood/page.aspxc=2...,42348&ap=1

Magnet Size Magnetic Strength

1/4" x 1/10" 2.5 lb

3/8" x 1/10" 5 lb

1/2" x 1/8" 9 lb

3/4" x 1/8" 22 lb

1" x 1/8" 30 lb

38.2k · December 21, 2006

You can always start here: http://www.leevalley.com/wood/page.aspxc=2...,42348&ap=1

Magnet Size Magnetic Strength

1/4" x 1/10" 2.5 lb

3/8" x 1/10" 5 lb

1/2" x 1/8" 9 lb

3/4" x 1/8" 22 lb

1" x 1/8" 30 lb

I use the 3/4" x 1/8" magnets from Lee Valley. They are strong enough that you can put them inside the container and they will still stick. That way you don't have to worry about glue or any other method of attaching it to the outside.

December 21, 2006

I noticed the local Lowes has a nice selection of magnets. I'm sure they are nothing super-powerful, but they have all types of sizes and shapes.

9.3k · December 21, 2006

If you have a dead computer hard drive, you can open it up and find at least one super magnet. Sometimes two.

These are strong enough that just one will support an empty ammo can.

December 21, 2006

I was watching a show the other day where they were using earth magnets to hunt for meteorites (iron) and they said you had to be careful using them because they are so powerful that if you get your finger stuck between the magnet and the metalic object it can be quite painful.

2.3k · December 22, 2006

If you have a dead computer hard drive, you can open it up and find at least one super magnet. Sometimes two.

These are strong enough that just one will support an empty ammo can.

I go to an electronics/computer swap meet monthly, where they have dead drives for $1. Along with the nice big super magnet, you get a couple of disks for signal mirrors, and aluminum case you can cut for tags for your multi-caches.

Some vendors sell the magnets from laptop drives (2.5"), two magnets for $1.

9.1k · December 22, 2006

When buying magnets, be sure to test them at the store to be sure they're not defective. Hold a magnet in one hand, then put another magnet near it. If they stick together, both magnets are OK. If they don't, one of them is broken. Pick up a third magnet and test it against the first two, to find out which one works right. Then with your two good magnets, repeat the process until you have all the magnets you need for your project. I have found that roughly half of the magnets are backwards. I am guessing they were imported from the southern hemisphere. If someone from Australia needs about 20 magnets, there is a Lowes in suburban Pittsburgh that has them. PM me and I can work something out with you.

38.2k · December 22, 2006

When buying magnets, be sure to test them at the store to be sure they're not defective. Hold a magnet in one hand, then put another magnet near it. If they stick together, both magnets are OK. If they don't, one of them is broken.

This is key. I started testing magnets in the store and found some not only don't stick, they ACTUALLY REPEL EACH OTHER!!!! I told the store manager and he seemed quite unconcerned. Needless to say I'm not shopping at THAT store any more.

7.3k · December 22, 2006

Yeah, but if those magnets won't stick to the OUTSIDE of your refrigerator, maybe they'll stick to the inside....

December 22, 2006

The true power of magnetism is not attraction, but the repelling action. The mag-lev train works on that principle.

Compasses were used by early explorers, not because the needle was attracted to the North, but because they repelled the North. Picture Coumbus setting forth-he did not follow that compass needle with the glow-in-the-dark dot on it to the North. He went South, following the needle end that repelled the North. He was heard to mutter, "Erm... icy North Pole...bikinis in Cancun. Which way should I go?"

I was watching a show the other day where they were using earth magnets to hunt for meteorites (iron) and they said you had to be careful using them because they are so powerful that if you get your finger stuck between the magnet and the metalic object it can be quite painful.

There are many different strengths, some so weak that they barely attract, and others so strong that there are very clear warnings concerning how they should be used and stored. Some of the magnets I have removed from hard drives will pinch skin and can be quite painful to small kids. I never let the grandkids play with them.

1.4k · December 22, 2006

I have found that roughly half of the magnets are backwards. I am guessing they were imported from the southern hemisphere. If someone from Australia needs about 20 magnets, there is a Lowes in suburban Pittsburgh that has them. PM me and I can work something out with you.

No need to wait for an Aussie...I have found a simple way to repair those magnets. Take one of the defective "backwards" magnets and "flip" it as you would a coin. If you get enough revolutions, the action of the magnet spinning inside it's own field causes it to reverse itself. This seems to work about half the time. DO NOT do this with properly polarized magnets as it can reverse those as well, making them useless N of the equator.

December 22, 2006

If that doesn't work, i've found that switching hands works. Swap magents from left to right, and right to left. It will fix itself.

December 22, 2006

If you have a dead computer hard drive, you can open it up and find at least one super magnet. Sometimes two.

These are strong enough that just one will support an empty ammo can.

Wish I would have seen this post about 2 weeks ago. I just threw out a bad hard drive.

December 22, 2006

I sorry if this sounds like a stupid question but........whats an Earth Magnet and whats it used for? Is it just another name for a regular magnet? Or is it something special? I have never heard that term before I started GC. Thanks

3.3k · December 22, 2006

I sorry if this sounds like a stupid question but........whats an Earth Magnet and whats it used for? Is it just another name for a regular magnet? Or is it something special? I have never heard that term before I started GC. Thanks

This a referral to Neodymium magnets.

December 23, 2006

If you have a dead computer hard drive, you can open it up and find at least one super magnet. Sometimes two.

These are strong enough that just one will support an empty ammo can.

Are you kidding me?? How do you get it out? We just dumped two old computers either to the recycle place or the goodwill, depending on the parts. Saved the hard drives. They're sitting in arm's reach. How do I get the cool magnet out? Insert image of cavegirl banging rock against hard drive here... :huh:

2.3k · December 23, 2006

If you have a dead computer hard drive, you can open it up and find at least one super magnet. Sometimes two.

These are strong enough that just one will support an empty ammo can.

Are you kidding me?? How do you get it out? We just dumped two old computers either to the recycle place or the goodwill, depending on the parts. Saved the hard drives. They're sitting in arm's reach. How do I get the cool magnet out? Insert image of cavegirl banging rock against hard drive here...

Its a good thing that you kept your drives because someone can get to your personal data. If they are functioning drives, you can get a USB drive enclosure and use them for external backup.

How you open them is to use torx screw drivers, size T8 should work. Some of the inner parts use another size. Just keep removing parts and you will see the magnets under a bracket, attached to another bracket. They are glued to this bracket. For some uses, you can leave them on this bracket, just epoxy the bracket to your container, or place it inside of your container, magnet side out.

December 23, 2006

Sometimes you can just pry them loose with a screw driver. I have loads of them.

WARNING be very careful cos they can snap together and do some damage to fingers, but they are really strong.

1.2k · December 23, 2006

Since reading this thread I retrieved one of two dead hard drives I had sitting around. I never knew what a powerful magnet I had all along. I never would have thought such a strong magnet would actually be inside a hard drive of all places. I would have expected it to erase the disk.

Not having the proper screwdriver, I had to physically rip the drive to pieces, one fragment at a time, which cost me a lot of time and a little blood, but it was worth it. I was just trying to think of how to make a magnetic regular cache. I'm really glad I read this one. :huh:

December 23, 2006

When buying magnets, be sure to test them at the store to be sure they're not defective. Hold a magnet in one hand, then put another magnet near it. If they stick together, both magnets are OK. If they don't, one of them is broken.

This is key. I started testing magnets in the store and found some not only don't stick, they ACTUALLY REPEL EACH OTHER!!!! I told the store manager and he seemed quite unconcerned. Needless to say I'm not shopping at THAT store any more.

I hope you are kidding ! If not, there is a real problem with science teaching in the US !

1.4k · December 23, 2006

When buying magnets, be sure to test them at the store to be sure they're not defective. Hold a magnet in one hand, then put another magnet near it. If they stick together, both magnets are OK. If they don't, one of them is broken.

This is key. I started testing magnets in the store and found some not only don't stick, they ACTUALLY REPEL EACH OTHER!!!! I told the store manager and he seemed quite unconcerned. Needless to say I'm not shopping at THAT store any more.

I hope you are kidding ! If not, there is a real problem with science teaching in the US !

It's true. I ve seen magnets actually push away from each other. It's like theres an invisible force field or something.

December 23, 2006

When buying magnets, be sure to test them at the store to be sure they're not defective. Hold a magnet in one hand, then put another magnet near it. If they stick together, both magnets are OK. If they don't, one of them is broken.

This is key. I started testing magnets in the store and found some not only don't stick, they ACTUALLY REPEL EACH OTHER!!!! I told the store manager and he seemed quite unconcerned. Needless to say I'm not shopping at THAT store any more.

I hope you are kidding ! If not, there is a real problem with science teaching in the US !

It's true. I ve seen magnets actually push away from each other. It's like theres an invisible force field or something.

OF course it is true, it is magnetism property !!!!! Same "pole" repell each other, opposite attract each other .

It is what makes work your compass, electric motor, particle accelerator, pigeon finds their way during migration etc...

My surprise does not come from that fact but from people not knowing it !

And it is not like an invisible force field, IT IS

9.3k · December 23, 2006

I'm not sure which part to laugh at loudest. :huh:

1.4k · December 23, 2006

I'm not sure which part to laugh at loudest.

:huh: Thank you.....I'll be here all week.

December 23, 2006

"Same "pole" repell each other, opposite attract each other ." (sic)

That's true. When I was a teenager, I went to a Polish wedding. Some of the Poles there were pretty repellent. Flies wouldn't land on some of the worst ones. But the bridal pair seemed to be pretty much opposites (one of them was a guy and the other one wasn't) and they sure seemed to be attracted - at least to each other. Not only that, one of the bridesmaids seemed to be attracted to anything in pants! So it must be true.

(Don't be a boar about it, suscrofa. Or do we have to twist an arm to be humerous?)

December 23, 2006

"Same "pole" repell each other, opposite attract each other ." (sic)

That's true. When I was a teenager, I went to a Polish wedding. Some of the Poles there were pretty repellent. Flies wouldn't land on some of the worst ones. But the bridal pair seemed to be pretty much opposites (one of them was a guy and the other one wasn't) and they sure seemed to be attracted - at least to each other. Not only that, one of the bridesmaids seemed to be attracted to anything in pants! So it must be true.

(Don't be a boar about it, suscrofa. Or do we have to twist an arm to be humerous?)

:huh:

6.5k · December 23, 2006

When buying magnets, be sure to test them at the store to be sure they're not defective. Hold a magnet in one hand, then put another magnet near it. If they stick together, both magnets are OK. If they don't, one of them is broken.

This is key. I started testing magnets in the store and found some not only don't stick, they ACTUALLY REPEL EACH OTHER!!!! I told the store manager and he seemed quite unconcerned. Needless to say I'm not shopping at THAT store any more.

I hope you are kidding ! If not, there is a real problem with science teaching in the US !

It's true. I ve seen magnets actually push away from each other. It's like theres an invisible force field or something.

Maybe you could arrange them just so a cache would float.... or would that be considered a traveling cache??

December 23, 2006

"Same "pole" repell each other, opposite attract each other ." (sic)

That's true. When I was a teenager, I went to a Polish wedding. Some of the Poles there were pretty repellent. Flies wouldn't land on some of the worst ones. But the bridal pair seemed to be pretty much opposites (one of them was a guy and the other one wasn't) and they sure seemed to be attracted - at least to each other. Not only that, one of the bridesmaids seemed to be attracted to anything in pants! So it must be true.

(Don't be a boar about it, suscrofa. Or do we have to twist an arm to be humerous?)

Thumb up !

Sorry to have been such a "boar"

(shot 8 of them this hunting season, biggest one was 130kg :huh:

9.3k · December 24, 2006

Sorry to have been such a "boar"

(shot 8 of them this hunting season, biggest one was 130kg

I wish the U.S. would adopt the Metric system as its standard for weight measurement. I'd weigh a whole lot less than I do now.

December 24, 2006

Sorry to have been such a "boar"

(shot 8 of them this hunting season, biggest one was 130kg

I wish the U.S. would adopt the Metric system as its standard for weight measurement. I'd weigh a whole lot less than I do now.

Not at all, your weight would be expressed in Newton !

If you want to keep the figure low without going through exercise or worse, a strict diet, just use the brits "stone" unit.

38.2k · December 24, 2006

OF course it is true, it is magnetism property !!!!! Same "pole" repell each other, opposite attract each other .

Why do you come here to speak such nonsense? There is no need to defend the manufacturers of defective magnets, unless of course you work for a magnet manufacturer. If that is the case then you should tell your management to pay better attention to quality control.

Edited December 24, 2006 by briansnat

9.3k · December 24, 2006

If you want to keep the figure low without going through exercise or worse, a strict diet, just use the brits "stone" unit.

Hmmm..... Not a bad idea...... 330 pounds =

299370.96 obolos

39916.13 momme

149.68 kilograms

23.57 stone

2.99 qintar

That's it! I'm moving to Arabia!

December 24, 2006

ive never heard of an earth magnet can someone show me a photo and tell me where i can get one at a standard store

6.5k · December 24, 2006

ive never heard of an earth magnet can someone show me a photo and tell me where i can get one at a standard store

Look at the magnets this place sells, or check out ebay. They're often coated in nickel (somethings other metals), and come in many sizes and shapes (squares, flat disks, round cylinders, etc).

Check out your local craft stores, like Hobby lobby, Micheals, etc. A lot of places have the black ferrite magnets, but you want the shiney silver colored (nickel plated) ones. They might be called 'rare earth', 'neo', or 'Neodymium' magnets.

9.3k · December 24, 2006

can someone show me a photo

Here's one with some of the hard drive components still attached.

and tell me where i can get one at a standard store

I've never seen rare earth magnets in generic stores such as Home Depot or Wally World, but then again, I'm not particularily observant. Many places sell them online, including Forcefield

Here is a fairly good article on these magnets.

December 27, 2006

Thanks guys, good stuff. I've actually got a roasted laptop harddrive laying around I'll dig into. Seems like this was a good question to get out there.

Maybe we can get a geocache container building/hiding area sometime soon.

We must shop at that same crappy hardware store. I went in to buy some 'L' brackets and they only put '7's in the bag.

Thanks again.

Jay W

505/287 Dakota

December 28, 2006

I have a few small ones I purchased at a Rockler store (woodworking) - but I am sure I could have got a better price if I had not picked these up - I just spotted them, figured they could be very handy for a number of things - and have only used a couple of the ten that came in the package. Rockler has an online store, also, in case you wish to look for them that way. (I won't bother to post a link lest someone think I am being overly commercial - so google it if you wish)

2.3k · December 31, 2006

Went to monthly electronics swap meet and picked up some electronics, electrical and computer items. Hard drive magnets were 2 for $1. I bought 4 of the large ones on the left., and they are strong. The middle one is from a 3.5", the right one is from a 2.5" drive.

January 1, 2007

Cool thread - gave me some ideas. I remembered those catalogs I used to get from Edmund Scientific when I was a kid, and the big magnet section they had, and looked them up online, and they're still at it -

http://scientificsonline.com/category.asp_Q_c_E_421188

Cool!

January 2, 2007

You can always start here: http://www.leevalley.com/wood/page.aspxc=2...,42348&ap=1

Magnet Size Magnetic Strength

1/4" x 1/10" 2.5 lb

3/8" x 1/10" 5 lb

1/2" x 1/8" 9 lb

3/4" x 1/8" 22 lb

1" x 1/8" 30 lb

I have a question kind of on this topic. On Mythbusters they did a show about the myth of Hollywood's movie "break ins." One of myths they tackled was using magnets to scale the heating/cooling ducts. Jaime had purchased 4 magnets that had 500lbs of pull. He made the comment that they were so strong/powerful that one needed a lic. in order to order/own them.

My question is why would one need a lic. in order to own a magnet regardless of how strong/powerful it is?

Digital_Cowboy

9.3k · January 2, 2007

Just guessing, but maybe it's a regional law? They film in Kalifornia, right? God knows there are some really strange laws there. :anitongue:

(sorry Kit, no offense!)

January 2, 2007

Just guessing, but maybe it's a regional law? They film in Kalifornia, right? God knows there are some really strange laws there.

(sorry Kit, no offense!)

That could be, but if anyone out there knows why I'd really like to know. They've also made other "strange" comments in the past on the show. Like "needing" an FBI agent or such on set when they fired a rifle into a scuba tank. Good show, but some strange comments.

Digital_Cowboy

20.7k · January 2, 2007

I have a question kind of on this topic. On Mythbusters they did a show about the myth of Hollywood's movie "break ins." One of myths they tackled was using magnets to scale the heating/cooling ducts. Jaime had purchased 4 magnets that had 500lbs of pull. He made the comment that they were so strong/powerful that one needed a lic. in order to order/own them.

My question is why would one need a lic. in order to own a magnet regardless of how strong/powerful it is?

He's kind of a wack job, so he may have just said that for 'color'.

January 2, 2007

He's kind of a wack job, so he may have just said that for 'color'.

That could be as well who knows.

Digital_Cowboy

January 2, 2007

Nobody mentioned the magnets in a microwave oven. Those babies are really powerful. I use them to hold some fairly big caches.

January 2, 2007

You can always start here: http://www.leevalley.com/wood/page.aspxc=2...,42348&ap=1

Magnet Size Magnetic Strength

1/4" x 1/10" 2.5 lb

3/8" x 1/10" 5 lb

1/2" x 1/8" 9 lb

3/4" x 1/8" 22 lb

1" x 1/8" 30 lb

Just received an order from leevalley. All I can say is wow! These things are powerful. Highly recommended. 1/2" magnets attached to both sides of my hand...no problem!

January 2, 2007

Nobody mentioned the magnets in a microwave oven. Those babies are really powerful. I use them to hold some fairly big caches.

Just be real careful tearing into one. the capacitor for the magnetron can carry a 10,000 v punch if it's not discharged

Magnet advice

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