Will these magnets run?
November 29, 2004 1:26 PM
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If you live in the US, you've probably seen them. Those yellow and red,white and blue magnets that people stick on their cars that look like ribbons, usually saying "Support Our Troops" or something of the sort. I've got a question about them. [MI]
I've seen a chain mail being passed around that the material these are made of is potentially harmful to a car's paint job when exposed to temperatures under 30 degrees Fahrenheit. Does anyone know how valid that is?
posted by shawnj to grab bag (34 comments total)
You know those yellow magnetic ribbons you see on cars these days? Eventually they can eat through the paint on most kinds of cars.
That flexible, magnetic material called Cemdex(TM) first came out in 1976. They tried to market it to the department of defense to use on big bulletin boards to track troop movements, but it never caught on.
Later it became used for promotional graphic arts purposes like business cards that stick to the fridge. IT WAS NEVER MEANT TO BE USED IN EXTREME WEATHER CONDITIONS.
Normally the flexible resins are completely inert and harmless, but if the material gets below 30 degrees Fahrenheit the resins can seep out and slowly dissolve the paint on your car.
The reaction: poly-iso-cyanate (the enamel in your paint) + polyvinyl resin (ingredient in the flexible magnet material) => polyvinyl acetate + 2 cyanic acid + 3 CO2
It will happen slow, but if you leave it on for an whole season, eventually you will have a big, gray, ribbon-shaped hole in your car's paint job.
posted by shawnj at 1:29 PM on November 29, 2004