Magnetic Money Clip/ Wallet

[azrider]

So I got a custom order the other week for a wallet with a magnetic money clip. The gentleman showed me the one he had been carrying for years, and said make one like this. Mythbusters says a magnet won't wipe a credit card, but creditcard.com says a constant exposure to a magnetic field will. Dude has been carrying his wallet for years he said with no issues. Has anyone made this type of wallet or dissected one of the commercial ones? What size and strength of magnet did you use? Any suggestions?

[Timd]

I use the 3/4x1/16" discs from: Emovendo I'm not sure about credit card damage, I've only used mine for cash...

Edited October 26, 2011 by Timd

[TexasJack]

Somebody I used to do business with was handing out business cards that were magnetized so you could put them on a file cabinet or whatever. They had to stop because people were putting the card in their wallets and nuking their credit cards. Of course, the strength of the magnet will affect how far it might have an impact. Some of those rare-earth magnets are pretty powerful

[Northmount]

Strength of magnet is some concern, but to really wipe a magnetic stripe (or diskette or tape) requires an alternating magnetic field. If you just lay the magnet against the stripe, it may not do any damage (not guaranteed), but if you keep moving it around to produce field reversals, there is very likely going to be some damage.

A few years ago, I did a test on floppy diskettes, both 5 1/4" and 3 1/2". (People were paranoid about magnets close to diskettes.) I used a very strong large magnet. The disks were still readable. Dropped them in water, froze them, drove over them, bent them, damaged the sleeve or plastic case, but when I replaced the sleeve/case, the disk was still readable. As long as the bend was not so sharp that it caused a crease, it was okay.

Used a simple electromagnet on alternating current ... wiped all info and had to re-format. Some diskettes would not re-format as the iron oxide was permanently polarized. That is why you never drop your card on the devices that deactivate security tags. AC current induces a current in a strip in the security device and burns it out. So they are not reversible. It wipes your credit card.

So chances are, most people would get away with having a small magnet next to a credit card for a long time. But eventually, they will run into problems after repeated snap open, snap shut actions.

[Northmount]

Just an added thought about magnets and credit cards in a money clip or wallet. (Takes a little time for all the ideas to gel into something that makes sense!)

Where this dude's current money clip hasn't affected his card in many years ... The likely reason is the mating bar that the magnet snaps to is nearest the card, and is acting as a 'keeper' for the magnet and preventing the magnetic field from reaching the card. It's also not likely the magnet and bar line up with the magnetic stripe.

So from a designing point of view, make sure the metal bar is at least as large as the magnet, place it in the center of the flap so it doesn't line up over the magnetic stripe regardless of the direction the card is inserted, and keep the bar on the credit card side. Magnet away from the credit card.