I'm interested in winding my own pickups and am wondering what people's thoughts and experiences are with cast and sintered alnico magnets. As far as I know, the sintered variety - are created by compressing metal and heating it till fusion occurs - don't influence the sound since they have no contact with the coil - have magnetism channeled by steel bars that influence the behaviour of the coil - cannot retain magnetism on its own I've read that Fender uses cast alnico magnets and that they have a higher resistance than sintered (see http://www.kinman.com/html/toneWorkshop/perfectGuitar.htm for details on the above). I've also read that sintered magnets don't retain their magnetism on their own. Do alnico magnets retain magnetism longer than the sintered variety? Also, how important is it that the magnets are transported unmagnetised? I supposed that strong magnetic fields can demagnetise them. In saying this, is there a limit as to the number of times a cast alnico magnet can be remagnetised. Also, as a matter of interest looking at the Seymour Duncan site http://www.seymourduncan.com/support/seymours_q_and_a.shtml what is the process of remagnetising and calibrating pickups or magnets? What tools, other than a guass meter, are required?