: I'm proposing to use rare-earth magnets to retain the covers

: I know these things are strong. (try stacking 3 1" diam of these and
: sticking them on the inside bottom of a cast iron frying pan) But for a
: good hold, they have to be in contact. Will compressing some kind of
: gasket present a problem? Have thought about trying this myself, but have
: not done it so far. Rare earth magnets are fun .

: Grant

I use rare earth magnets on the flush hatches of my Shooting Star kayak.

You need a magnet to magnet contact for the strength needed to bridge the gap until your gasket compresses. I use gasket material available from Newfound Woodworks.

I use the 1/2" diameter magnets available from Lee Valley Tool;
http://www.LeeValley.com/

The magnets are recessed into the hatch cover and hatch lip on the deck. I use eight on the hatch cover and eight on the hatch lip. A total of 16 per hatch. This may sound like a lot but I did extensive research and found the number and configuration I'm discribing works the best.

The waterproofness was tested with rolls at last fall's Newfound Rendezvous.

Aligning the mating pairs is important. MAKE SURE THE POLES ARE ALIGNED SO THE MAGNETS ATTRACT, NOT REPEL!

You MUST BE WARE the magnets will effect any compass placed in proximity.

I found the magnets effected my compass if it came within 18” of the hatch cover.

If you would like more detailed information on making flush hatches closed with rare earth magnets contact me.

All the best,
Rob