I've only seen them in round. They come in various strengths. I got mine at Hobby Lobby. I used four 1/2 inch #10 strength ones to secure my griffen crest. I drilled some 1/2 inch holes into the underside of the crest, packed in a little plumbers epoxy putty, and then shoved the magnets in the holes. Haven't had any trouble with them pulling off the crest. For wings, I'd try two 1/4 inch magnets per side (since the helm is curved). As for stability, with #10 rare earth magnets, I practically have to pry my crest off!
Each of these discs has a pull force of over 25 lbs.
This is what I used.http://shop.hobbylobby.com/store/item.aspx?ItemId=160468
That is an excellent question...and a valid one at that. No matter how strong the magnet, if the helm is stainless you won't get any sticking going on.
Quote from: Sir William on 2011-09-12, 15:29:00That is an excellent question...and a valid one at that. No matter how strong the magnet, if the helm is stainless you won't get any sticking going on.A second magnet glued inside the helmet *might* take care of that; seems like the magnetic force that strong could work through steel, but I'm sure at a cost to it's potency. Great point, Sir Brian.