How to stop Cutlery heating under an induction hob?

Printsofwhales

Contrary to statements on a thread which is now closed, our cutlery DOES heat up when the induction hob is on. I am not sure why the claim is made that cutlery is not magnetic - all ours can be picked up with a magnet, so obviously some can be magnetized and therefore can be heated by the hob. Is there any thin yet stuff material I could place underneath the hob to reduce this? Our kitchen layout suggests no obvious place near the cooking area. Swapping drawers around seems not to be an option as then the pans would heat up instead.

Printsofwhales

"Stiff" not "stuff"

NewShadow

Have you tested it to see if it's actually heating up? The fields under an induction hob are very weak and normally the depth of a drawer would be sufficient air gap so it would be very, very unlikely for the hob to actually have an effect; possibly an overly full or very small drawer - but then how could you use it for pans?

You can't insulate against magnetic fields the way you do for heat or electricity - you can place a conductive sheet under the hob, but then that sheet would simply divert the magnetic field and itself heat... which would be less than ideal. 

I would suggest the cheapest option would be to buy a new set of cutlery  

FreeBear

Mu-metal is a very effective shield against magnetic interference. But it is expensive....

 A lot of cutlery is made from martensitic stainless steel which is magnetic. Even austenitic stainless steels are slightly magnetic - Both would heat up in the presence of an induction hob. The only real option is to move the cutlery draw to a different location (I have mine in the adjoining unit to the hob).

ka7e

Are you sure it's not the cooling fan distributing heat in the drawer? I have my stainless steel cutlery under the hob and it gets very slightly warm, as do non-ferrous utensils in the drawer.

TELLIT01

Moving the cutlery draw isn't always a practical proposition.  Thankfully we have a gas hob, but the cutlery draw is in the top of an 800mm wide pan drawer immediately beneath the hob.  No other 800 mm wide cabinets to move it to - no other drawer cabinets at all come to that.

FreeBear

Could always fit an internal drawer to a cupboard unit - https://www.kitchendoorsonline.co.uk/blum-kitchen-drawers-and-drawer-kits/shallow-internal-drawer

NewShadow

FreeBear said:

Mu-metal is a very effective shield against magnetic interference. But it is expensive....

There's no need for expensive alloys - any ferromagnetic metal would do the same thing - the only benefit of using specialised magnetic shielding materials like Milspec 14411C/MuMetal is that the sheet could possibly be thiner due to it's higher relative permeability, but that has to be balanced by it's relatively lower saturation point.
 
If I may articulate again my concern with such an approach - magnetic shielding doesn't 'block' magnetic fields - it simply redirects them through the sheet, bypassing the drawer. Given the field densities for induction cooking, my concern would be that any such sheeting would heat - possibly even to a higher temperature than the cutlery in the drawer due to proximity - therefore could itself pose a danger... 

Jackmydad

Put a metal table knife, and a plastic table knife in the drawer, a couple of inches apart, but directly under the hob. 
Use the hob.
Measure the temperature of the two knives. By feel if you don't have an IR thermometer.
If they're the same, then it's direct heat from the hob in some way, and not induction heating.