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I’m converting a simple cooking hot plate to have it’s temperature controlled by an arduino, with an lcd.

It’s metallic casing gets really hot when the plate is turned on.

As I’ll remove the original analog temperature control and use an arduino and thermocouples to control the heat, even I I had space under the heat element, I think it would toast the electronics pcbs and lcd.

So I’m thinking of using an external enclosure to put the arduino, lcd, rotary dial and sensors connections.

But I want to keep this enclosure attached to the metal frame of the cooking hot plate, not hanging around with cables.

Is there a material to isolate the heat from the metal case from the hot plate to an external attached enclosure, so the circuitry will be in an “acceptable” temperature? Something to be put between the metal frame and the enclosure? Silicone rubber?

I don’t have the enclosure yet. A plastic one would be easier to make holes, but it can be an aluminum one also.

Thanks!

The hot plate is this one attached. hot plate

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    \$\begingroup\$ Probably not. Anything between the counter and the pan will get warm \$\endgroup\$ – Chris Stratton Sep 9 at 2:51
  • \$\begingroup\$ Connect enclosure to hot plate with posts and add a fan. \$\endgroup\$ – DKNguyen Sep 9 at 2:53
  • \$\begingroup\$ Search for Kaowool. \$\endgroup\$ – Brian Drummond Sep 9 at 11:16
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An enclosure under the hotplate will work perfectly fine, provided there is an air gap, the existing rubber feet would be sufficient, The hot plate creates convection currents of air that pull cold air in from the sides. If you wanted to run the hotplate continually at very hot settings (> 200C) then a thin metal plate spaced 5mm above your enclosure would add additional "insulation". I've got almost exactly the same hotplate, and I just used a piece of 10mm plywood, screwed that to the base of the hotplate (after attaching a thermocouple to the central screw under the hotplate), and then attached a plastic framed 1/4DIN temperature controller next to the hotplate, this worked well, I only used it to about 210C to reflow solder.

(a) Normal mounting under hotplate unit:

(a) normal under mount

(b) Add a metal spacer plate if using at high temperature for extended period, or heavy items on hotplate and a plastic enclosure, a piece of thick aluminium foil (from disposable baking tray would suffice) air gap >= 5mm.

B spacer

(c) A sheet of plywood works fine under the hotplate, it is what I did, it gets a bit warm on top (but not as warm as if left in the sun!), the wood didn't warp, so can't be "too hot"

(c) plywood under

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  • \$\begingroup\$ That's exactly the reason I want to do it! To do a DIY reflow plate. I liked your design of the plate over a playwood base and the control unit attached to it laterally. Do you think If I screw a 1CM thick round smooth aluminum plate over the original hot-plate (with the same diameter) the heat would be better distributed evenly over the aluminum surface? \$\endgroup\$ – Rodrigo Sep 12 at 18:56
  • \$\begingroup\$ Aluminium has a much higher TCE (Thermal coefficient of expansion) so screwing it on will work only if you have slots , (or if you have only one screw). I'd pnly add a square plate so I could get more PCB's on. The limiting thermal transfer is across the air gap between PCB and hotplate, and the hotplate is black and rough so you get some radiant heat transfer. I do have a 3mm thick aluminium plate, but I use that to slide the PCB's onto to cool off. \$\endgroup\$ – BobT Sep 12 at 21:51
  • \$\begingroup\$ I now use a toaster oven to do reflow (with same temperature controller) the hotplate is too slow to get a good profile. With the oven I heatsoak (bottom element on) at 170 to activate the flux.Then turn both elements on & set temp for 205, when I get there, and have observed reflow , I turn elements off, open the oven door and pull the slide out to let PCB's cool down. When the local fab shop had an oven failure we pushed 200PCB's through the toaster oven 8 at a time. \$\endgroup\$ – BobT Sep 12 at 21:58

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