Niko --- --
The CD RW drives you harvest diodes from have at least 2 very powerful magnets in the head. You should have a bunch by now. Some sleds have 4 magnets. I don't know what they are made of, but they are strong.
Mike
I tested acouple of mine and they run 2,000 to 2,200 Gauss.
A friend gave me a couple magnets used in glass making. They are 3/8" square and about 2" long. Awsome -- test at 4,200 gauss !!! Maybe you can find a place making glass that uses them. They are replaced occasionally.