Magnets. How do they work?

I don't care how they work, just that they do.  I landed a Dreadnought from Zombywoof on the SPR forums, complete with multiple weaponry.  I've read the pros and cons about magnetizing certain models, and while I don't give a rip about "model pose-ability," I did become intrigued with the "one model, multiple set-ups" idea.  You see, I'm not new to painting, just gaming.  I'm attempting to collect, paint, and eventually field a 1500 pt Imperial Fist force.  I'm going by the basic Drop-pod army list posted on GW's webpage for sample armies.  This particular list calls for one dread with a multi-melta and heavy flamer.  Just listening to Zombywoof explain the differences in weaponry, made me think about trying the magnets thing.  So, here's how and what I did and the final results.

First, there were some tiny tiny weak magnets on the chassis and some of the weapons.  The result was droopy non-sturdy weapons.  I had some magnets I picked up from A-Games for no reason a few months back that are 6mm in diameter.  I dug out the old magnets which were green-stuffed and superglued in place.  (There's magnets between the chassis and legs, but I glued those pieces together giving the dread the appearance of twisting to take on a new threat...I don't know if it'll affect game-play or anything as in, where is the front of the model...for me WYSIWYG so the front is the direction the "head" is facing.)  I then took my standard Black and Decker cordless drill and a bit the same diameter of the magnets; and drilled the holes out of the arms/weapons and the chassis, being careful not to go through the pieces.  (If the hole was too deep, I kept the magnet from glueing in too far by using a paperclip.  I did ignore the polarization of the magnets for the chassis and paid attention when I worked on the weaponry.  Note:  I am, indeed, now aware that the legs are on backwards.  Thanks to Grey-Clad Stranger and itmademeregister with SPR.

Next was glueing the magnets on the arms.  Now polarization is pertinent.  Fortunately these magnets were strong enough to pull through my finger and I could figure it out pretty quickly.  I did the paperclip trick again to keep the magnet flush with the model so as not to set it too deep in the arms.

I know, no multi-melta, but another SPR fellow, Master Shake, is going to hook me up.  Here is the model with two different weapons set-ups.  The magnets are actually strong enough to pick the whole dreadnought up by one of the arms.

Now to prime this badboy with TAP's Daemonic Yellow, let it dry, then pack it and everything else up for the impending move.  Thanks for looking.