Oven safe magnets?

May 2, 2007 1:46 PM

My Bosch oven door has gradually stopped closing entirely, unless I prop it shut. I have dissected the spring hinges, and cannot figure out the cause of the problem. Propping the door shut takes hardly any pressure, so I've decided to fit magnets on the inside of the door so it will auto-close. There is space for magnets up to about 1cm deep each. Which magnets should I buy, taking into account cost, strength, heat stability, and possible toxicity?
posted by roofus to home & garden (13 answers total)

I don't think this is the proper solution. I think you should get a real repairman to come and look at it.
posted by Steven C. Den Beste at 2:07 PM on May 2, 2007

The better the magnets, the harder it will be to open the door.
posted by phaedon at 2:23 PM on May 2, 2007

Replacement hinges appear to cost about $80 a piece, so I'm prepared to experiment before calling in a pro.
posted by roofus at 2:25 PM on May 2, 2007

Magnets will probably lose their magnetism fairly quickly when exposed to that much heat.
posted by Malor at 2:44 PM on May 2, 2007

Magnets + heat = no more magnets

http://en.wikipedia.org/wiki/Magnet#Demagnetizing_materials

I second the repairman advice.
posted by tdreyer1 at 2:44 PM on May 2, 2007

Velcro
posted by found missing at 3:07 PM on May 2, 2007

Why not use child proofing oven locks ? They work well for us and our toddler. You may not want the extra step of "unlocking" but you'll know that they're built for use around ovens.
posted by cocoagirl at 3:16 PM on May 2, 2007

I think the oven lock might be a good idea. My father dealt with a dryer that didn't latch properly by drilling a plain sliding bolt onto it.

I wouldn't drill onto your oven, but perhaps some sort of ultra-super-extra-powerful glue and a sliding bolt might work if that $5 device linked there doesn't.
posted by cobaltnine at 3:47 PM on May 2, 2007

Well, you have to look at what is called the Curie point of a given magnetic material. Beyond that temperature, the magnet demagnetizes, and what you have is a lump of expensive alloy. So, the question becomes, what is the temperature that part of your oven reaches? It's probably not 400 F, but I'd bet it's fairly warm.

Oven doors get a lot of slamming, so the other factor you have to think about is brittleness.

Toxicity is not really a factor. You spray oven cleaner in your oven, right? You're not actually eating the magnets? No worries.

Neodymium magnets are very, very strong, but they lose their magnetism above 176 F (80 C). There are neodymium magnets that can operate up to 200 C, but they are not quite as strong. You'd probably want a samarium-cobalt magnet, for those temperatures. The downside of both of those kinds of magnets is that they are rather breakable. They just like to chip away, due to brittleness. So, those are out.

Next down on the strength chart would be ceramic magnets, but these are, again, fragile. A good working temperature for these is about 300 C (572 F).

Don't even think about flexible magnets, they melt before they hit 400 F.

So, what are we left with? Good, old-fashioned, dirt cheap alnico magnets. Get a bunch of them, they won't cost much. I'd love to know how it works out.
posted by adipocere at 3:57 PM on May 2, 2007

As a temporary measure, I installed velcro strips, and thus far it's working well. However I'm going to pick up some cheapo magnets over the weekend, and I will report back on how well it works.
posted by roofus at 12:52 AM on May 3, 2007

Talk to Mr. George the magnet man. He can find anything you need.
posted by Soulbee at 5:17 AM on May 3, 2007

If something else isn't obviously broken on the hinges I'd suspect the springs. You might be able to find stiffer springs at a hardware store, though there may be a small range between too stiff to stay open when the door is down and not stiff enough to stay closed.

In any event, have you tried calling Bosch and explaining the problem? It sounds like a design issue to me.
posted by 6550 at 9:00 AM on May 3, 2007

I've no idea what your oven looks like but is their any possibility that enough crap has fallen down into the space where the hinges are that the door no longer closes? Could action to address that solve the problem? We cleaned our oven out the other day and there was masses of bits of carbonised food, etc down there.
posted by biffa at 4:41 AM on May 4, 2007