What Magnet strength / type do I need for this DIY Poster Holder?

April 7, 2017 2:46 AM

I want to recreate this: Close Up Image of Poster Holder

I am buying magnets from here: http://www.first4magnets.com

I am going to buy some rounded half crown molding and then cut it down to size and also cut the holes for the small magnets myself.

Problem is, I have no idea what strength / size / type magnets to buy.

I need strong enough to clamp light(ish) poster board width between the pieces of wood, but also not so strong that it damages the poster, or the wood, and also so I can in future swap out the poster!

Additionaly I have a dremel, aside from the routing attachment, how can I cut the necessary depth/width holes in the molding - for the magnets - without going entirely through the wood?

Help?

posted by Faintdreams to Sports, Hobbies, & Recreation (6 answers total)

Best answer: I've been using round ones similar to these to hold up various stuff on my noticeboard, as well as to turn random items into fridge magnets. The ones in your picture look to be a bit smaller (maybe 6mm) - choose a size that's quite a bit narrower than the moulding to avoid splitting the wood.

Routing with a Dremel seems like it might be a pain. I just use a 10mm drill bit to make a very shallow hole. As long as the outside edge of the hole is the right depth, it doesn't really matter if the hole is a bit concave - just dollop some epoxy in there, sit the magnet in so that it's flush with the sides, and allow to set.
posted by pipeski at 3:49 AM on April 7, 2017 [2 favorites]

I'm pretty sure you want neodymium magnets. I'm seeing them advertised as *rare earth supermagnets* but when they're small they aren't too strong. Have you ever played with a magnet pulled from a hard drive? They're like that, same thing, except smaller so less powerful.
posted by mammal at 6:32 AM on April 7, 2017

Best answer: You can put a bit of tape on a drill bit as a depth marker.
posted by exogenous at 7:25 AM on April 7, 2017

Response by poster: Thanks everyone I'm all set to make my poster holders now!
posted by Faintdreams at 11:16 AM on April 7, 2017

In a handheld drill you want to use a brad point drill bit; if you have access to a drill press use a forstner bit. Both these bits cut a nice clean hole and neither self feed allowing you to control the depth.
posted by Mitheral at 12:33 PM on April 7, 2017

Best answer: One other thing (which you've probably thought of): make sure all of the magnets on each side are pointing in the same direction - so N N N on one strip, S S S on the other. Otherwise you may find that your poster holder only works one way around.
posted by pipeski at 3:34 PM on April 7, 2017 [1 favorite]