Magnetic Knife Rack Failure?

S

sludge7

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May 28, 2016
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Hello -- apologies if I've posted this in the wrong place...

The kitchen I work in stores its knives on two magnetic knife racks. Cheap and nasty ones, but they have worked fine for several years. Lately, it seems to be easier and easier to just nudge the knife next to the one you're picking up and have it fall off the rack. I thought a Google search would give me the answer to this, but apparently not.

Is it possible that the magnets are somehow becoming de-magnetised? I understand if the knife rack wasn't strong enough in the first instance, but this is something that seems to have happened over time. Is it fixable? Can we re-magnetise it? Any thoughts more than welcome.

Many thanks,

Jessica
 
Permanent magnets may lose their strength. For your case, the only plausible reasons I can think of are mechanical stress, such as vibration and impacts, or exposure to other magnetic fields, caused by other magnets, or electrical currents (the last one is very unlikely). In principle you can re-magnetize them, but if they are cheap and nasty why not get new ones?
 
Yea they will become weaker over time, although I always forgo the knife wall and hide a few rare earth magnets on my station to hold my knives, thermometer, etc. Do you bring your knives home or are these the beaters for everyone?
 
Wake up ancient thread!

I have just one Henckels pairing knife that will no longer "stick" to my ~15 y.o. knife rack in some spots on the rack. Almost zero attraction in these spots, but move it over slightly and it's fine. No issue with any larger knife. This lack of attraction has seemed to have gotten worse over time. Does the issue lie with the knife or the rack?

And like the OP -- either way, can you remagnetize either the knife or rack?
 
Happy Necro Thread Day!

Heat will demagentize magnets so consider the placement of your magnetic rack in the kitchen.
Lower levels of heat will cause some reversible damage to magnets, while higher heat can cause permanent damage to magnets, depending on the type of magnet.

Of the four main magnetic materials, alnico magnets have the highest maximum operating temperature.
Alnico magnets will not suffer irreversible performance losses until reaching 535°C, or 1000°F.
In second place, we find samarium cobalt magnets, with a maximum operating temperature of 300°C, or 572°F.
Ceramic magnets are in third place, with a maximum operating temperature of about 250°C, or 480°F.
Finally, in last place, we see neodymium magnets, with a typical maximum operating temperature of 80°C.
While standard neodymium magnets have a maximum operating temperature of 80°C, or 176°F, new high temperature neodymium magnets have been developed.
These high temperature neodymium magnets can be safely used at temperatures of up to 150°C, or 302°F with some special grades capable of performing at temperatures of up to 200°C, or 392°F.
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Question. If the knife becomes magnetic. Wouldn't that interfere with the magnets? Depending on which pole is stuck to the magnet?

Because I'm on the hunt for a nice piece of hardwood to make a rack. Thinking to myself, it's going to make my knives magnetic just like rubbing a screwdriver across it.

Plus, those rare earth magnets are expensive. Being so rare. That every hobby lobby from sea to shining sea has them.
 
gajahduduk said:
Good questions grasshoperglockl. maybe that's what's happening? the knife is magnetized and the polarity is wrong?
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Doubtful. Can you see the magnets in your rack? Most that have hidden magnets use small magnets spaced a couple of inches apart and larger knives can span the gaps easily, but smaller knives can have issues in the "in between" spaces, and it gets worse as the magnets weaken.
 
In my experience, small embedded magnets have worked perfectly--but partly because I didn't "push the envelope." My wood mounted magnetic strip has stuck in place on the side of my fridge and held 7 or 8 knives base down--none more than 9" and/or 250 gm. I have a separate holder with slots for heavier knives like my deba and cleavers--with a magnet holding each in the slot: approximately 350 gm. Neither of these magnetic holders have shown any signs of deterioration over the last five years.

I've recently purchased a magnetic saya for a new knife that holds my blade in place without moving around.

Magnets are your friend!
 
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