Anyone know about magnets?

Chiro75

Chiro75

Joined
Feb 4, 1999
Messages
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I have a project in mind for some of my messenger bags that have Velcro closures. The idea is to cut some pieces of Velcro to fit the sewn-in Velcros patches on the bag, but within these strips to place some magnets. In this way, the Velcro I add will essentially be a "silencer" but with strong magnets would still allow the bag to hold shut. Coupled with the plastic clips on, say, a Timbuk2 bag, it wouldl be plenty of hold, but if I needed more, I could simply pull the silencers off and the Velcro is there to bind again.

I don't know much about magnets, though, so my criteria are that:
1) They should be pretty thin
2) Pretty small (like maybe a 1" diameter, tops)
3) Strong
4) Cheap

Any ideas?
 
I have purchased some of those rare earth magnets - or whatever they are called - off of ebay. Got them just to play with.

Sweet Mother of Pearl, those things are powerful. As in, a pair of 1" cubes will tear the end of your finger off if you aren't careful. I started storing them outside, and finally threw them away. Too dangerous.

But you should be able to get tiny ones that are useful for your needs. Even ones the size of an Altoid mint would be very powerful.
 
Yes, those larger sized magnets are very dangerous. I've read about a toddler walking past a table that had one on it while holding one in his fist. He lost a couple of fingers...

I don't know if this story is true or not, but it makes me wince at the thought of it. A man placed magnets in opposing pants pockets. Let's just say that very loose pants were involved.
 
And keep in mind that I ain't gonna put my laptop with its hard drive in a bag with any magnets. Even a wallet with cards with mag strips are a no-no in a bag with strong magnets.
 
Those neodymium (rare earth) magnets are serious. I've given myself blood blisters by accident a couple of times. If they don't suit your needs, you'll have to turn to extraterrestrial technology.
 
I have gotten a few things from these guys.

D2503.jpg


Just for kicks:

D7626.jpg


This is the largest magnet we sell. It is a frightening 3 inches x 1 inch and needs to be handled with an extra dose of caution. It can hold hundreds of pounds and has a field that will effect a TV or computer from over 6 feet away. Shipped in a wooden box with a steel lining for field containment. This magnet weighs 4 lbs, but it ships at 7 lbs with the extra weight of the packaging materials.
Click to expand...
 
Gollnick said:
And keep in mind that I ain't gonna put my laptop with its hard drive in a bag with any magnets. Even a wallet with cards with mag strips are a no-no in a bag with strong magnets.
Click to expand...

What he said!!!!!!

Be real careful what you put in that bag. It doesn't take much of a magnetic field to start messing with hard drives and the like.
 
Watson-349 said:
Yes, those larger sized magnets are very dangerous. I've read about a toddler walking past a table that had one on it while holding one in his fist. He lost a couple of fingers...

I don't know if this story is true or not, but it makes me wince at the thought of it. A man placed magnets in opposing pants pockets. Let's just say that very loose pants were involved.
Click to expand...


one can build a very deadly mousetrap using these magnets............... :cool:
 
Watson-349 said:
Yes, those larger sized magnets are very dangerous. I've read about a toddler walking past a table that had one on it while holding one in his fist. He lost a couple of fingers...

I don't know if this story is true or not, but it makes me wince at the thought of it. A man placed magnets in opposing pants pockets. Let's just say that very loose pants were involved.
Click to expand...
We have two pair of 6 inch diameter rare earth magnets that are a part of a filter system. Every so often someone gets two of them stuck together. They're clad on the top and sides in stainless steel that forms a handle. I'm constantly telling the knuckleheads to be careful with them. We have to take them back to the shop, put one of the handles in a vice and bulldog the other one off. You can't pull them straight apart but you can slide them off each other. Takes quite a bit of force to do so.

Anyways, I'm taking a pair that I just separated back to the filter, one in each hand. The one in my right latches onto to my keys that are hanging from my belt. These things are heavy, so intead of lifting it straight out, I swing it across the front of my legs to free my keys. I must have unconsciously moved my left hand towards my right. Those two unholy magnets slapped together a few inches in front of my happy area. Once they get close enough, they slam together in a uh-oh second.
 
George Risk Industries (GRI) - makes several diameters of very small rare earth donut magnets that are used in the alarm industry as min. size replacements for much larger ceramic magnets that are installed opposite magnetic contacts aka door switches.
Even the roughly 1" round by less than 1/4" thick versions will really clamp together.
 
If you have access to any old computer equipment, just take apart a couple of hard drives. Free magnets.
 
The stray magnetic fields can be greatly reduced by putting the magnets in a steel/iron cup and using a steel plate on the other side to hold against.

A rare earth magnet 1 inch in diameter would be way over kill. Think more .25 diamter and 1/8 inch thick. DOn't go thinner then 1/8 inch as they are fragile and easy to break in thing section. You local hardware store will likely have some smaller size for two or three dollars you can experiment with

see:

http://www.kjmagnetics.com/products.asp?cat=110
 
Deal Extreme has them for a pretty good price and that comes with free shipping too. One thing to note though is that some buyers have noticed that the magnets can be a bit brittle but for your application I doubt that would matter. They are very strong. I bought a few to hold up notes and tuff on the whiteboard in class. The kids had a good laugh cos it was a real pain getting the stuff off.
 
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