My fave trick, cheap and environmentally conscious, reuse broken speaker
magnets.
Poke around in the dumpster behind a car audio installation shop, speakers
will have a magnet relative to their "bump power". The really huge ones may
be too powerful to remove from a surface.
tear the accessories off the magnet. Heat the magnet sandwich to melt the
hotglue that holds the steel on. When it's nice and hot, drive a singleedge
razor blade (have plenty on hand) between the magnet and the steel disk. How
you hold the hot round part as you tap on the blade is left as an exercise
to the reader.
 What you get is a torus shaped magnet of any size you can scrounge, some
huge, some small. The largest is 4 inches in diameter. I have several in my
van for keeping track of things, including a homemade cupholder stuck to the
dash.

CAUTION! Keep your laptop and iPod away from strong magnets!

-- Gnarlie

Entity Jim Felder spoke thus:

> Older vanagons, at least the diesels, have a painted steel dash with no
> padding. This makes them useful for using heavy-duty magnets to hold
> things down. I've always wanted a magnet for a 12v fan, and I recently
> got one. Harbor freight has welding grounds on sale for half price,
> under four dollars.
>
> Throw away the spring and ground screw from the center. Glue some
> headliner material to the bottom (2 reasons: it won't scratch the
> paint, and without some distance between the magnet and dash, you
> almost can't pull it off with your hands) Most fans I've seen have a
> provision to screw the clip-on base into a shoe for permanent mounting.
> Screw the shoe to the magnet and attach the fan to the shoe.
>
> Now you can have a fan anywhere in the van you can find a metal surface.
>
> If you want a photo, just ask.
>
> Next I want to use two of these magnets to mount a rain awning over the
> sink-fridge window. Will post that when it happens.
>
> Jim