I'd like to try using some Rare Earth magnets for door catches on my flush inset cabinets. It's a paint job and I'd like to use them in the top and bottom of the door and the inside of the face frame, then bondo over them. I did some looking, and apparently, there are a zillion magnet sizes and strengths available. What's worked for you?
From contributor P:
I've used them a couple of times. Lots of work, compared to regular magnet catches. 3/8 x 3/8 cylinder should work, depending on the size of the door. You want the neodymium magnets.
Use a magnet on the door, and a screw-in "cup" that's countersunk into the face frame. Make sure you get the polarity correct. Never tried the bondo idea. Might work.
I doubt you would need top and bottom. I would think one placed on the bottom corner of the knob side, maybe 1 1/2 from the stile of your face frame. (Gives you enough room to get your cordless drill in there with running the chuck into the stile.)
You would only need 1/16 of an inch of bondo. I would drill a 1/4" whole then use a countersink to give the bondo some wood to grab onto besides the magnet. That plan would use a 1/4D x 3/4" long Rare Earth. You could screw a steel flat head screw flush on the bottom of the door.
If you are trying to do this on the cheap, then only use one magnet. I think this is something that only you can tell by trying for yourself and then deciding what kind of a cabinet you want to sell to your customer. Holding the two magnets as close together as possible will give you the strongest holding power. It is a soft hold to begin with.
I'm guessing that the idea of using bondo over the magnet is so you can paint it. I have never tried to paint a magnet, but I'm sure that if you use the right primer it would hold paint just fine. If you are using a hinge with a self-closing spring, the magnet will be a waste of time, but I'm sure you already know this. I have used magnets on cabinets that had a clear finish so you could see them and did not mind how they looked at all. The customer liked it so much that they had me do this on all their cabinets. I did this on over 80 doors and in nine years I have never had any problems. And yes, I still talk to them. I ran short when I was installing them and bought some other magnets that were not Rare Earth. I thought this would not make that big of a difference, but I was wrong.
The stronger the magnet, the better the hold. There is a big difference, so make sure when you buy them you get the right ones and make sure that when you drill the hole it is a tight fit. If there is any wiggle, the magnet will not stay in. I tried different sizes and found that the 4 millimeter worked just fine.