Builders' Forum Archives
Posted by Tony Calvert on Jan 8, 2005
My impressions a year on!
Would I do them again? Yes but.....
Here are some things that may prove helpful to anybody considering using rare earth magnets as a hatch hold down system.
If you are not going to use glass mat over the magnets as I did make sure you embed the magnets at least 1mm below the surface of the wood as anything less than this will be prone to rusting.
The edges of the hatches need to be totally sealed with epoxy, I had a pin hole that allowed water to seep in, it took nine months of paddling but the water eventually got to the magnet through the edge of the hatch and has caused it to bubble (photo attached).
I sealed my hatches with plain of silicone and it works well, even in the most demanding conditions they let very little water in. After an hour long rolling session I may end up with a cup of water in the boat. This amount has increased greatly with the rusty magnet as it raises the hatch breaking the seal with the silicone.
I was going for light weight on this boat and didn't glass the top of the deck and the inside of the hatches. On future kayaks I think I would do this and hopefully it would stop any seepage problems.
I was concerned about holding power but it has never even looked like being an issue, I have the hatches teethered so they can't float away but even when transporting (60-70mph) them I don't use anything other than the magnets. I have eight pairs of magnets holding each hatch and at times (cold fingers etc) they are a pain in the butt to get off because they hold so well.
Hope this helps anybody who is considering using magnets for hatches, I think it looks really good having a clean deck and I'm going to use the same magnet hatch system on a Sea Spirit I'm building for my wife but with a layer of glass over the area.
My Yak page