Electric lunch or bento box.

With the title truncated, I saw "Electric Lunch" which makes me imagine some hipstery cocktail from Seattle or Portland

I tried that once. It didn’t go well! I set the power to 100% by accident. After 10-20 seconds one of the paper satchels burst open, and spewed hordes of shattered pellets everywhere! 🤦‍♂️

Bo Holbo Rasmussen

I recharge those silica gel sachets by placing them on a folded paper towel and blasting them in the microwave for a minute or two.

Big Clive

That got me thinking about your “rechargeable” silica gel dehumidifier video from four years ago. I have the habit of collecting those desiccant satchels that you find in boxes of electronics etc. (I have way too many of them:-) I normally use my electric oven at 50 celsius to drive out the moisture... But that lunchbox looks like a MUCH better solution! Clive, could you do us (me) the favor of testing the temperature it reaches when its empty? Assuming it’s safe of course! 😉 The video I was referring to: <a href="https://youtu.be/n2vEaLSvQrc" rel="nofollow noopener" target="_blank">https://youtu.be/n2vEaLSvQrc</a>

Bo Holbo Rasmussen

Lid on and vent closed, but thermocouple cable providing route for steam egress.

Big Clive

You didn't mention - did you do the water test with the lid on (and vented or unvented)?

That was a rather extreme case with pasta lying at room temperature for five days. Interesting that tests on rice showed that even at just 30C the bacteria was less productive than at a lower room temperature.

Big Clive

Mmmm bacillus cereus... <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3232990/" rel="nofollow noopener" target="_blank">https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3232990/</a>

Electric Lunch Box sounds like a psychedelic band from the'60s

Hi Everyone. Well my Electric lunch box was a bit different from the one that Clive got. Mine has a stainless steel insert along with a smaller plastic one that comes out for washing. The PTC's in mine seem to be bit larger in size. Wish I had a HOPI to check mine. I have found that wrapping a small towel around the box helps greatly. It has successfully heated about 250ml of beef stew to 60C from 7C in 1 hour with a ambient temp of 20C. I have used it for the last month with no issues. It was purchased from Amazon for about $20 dollars US. I have bought two different versions. The other one is much like a TV dinner tray with three compartments. One large and two small. Also stainless steel. The only drawback is that the separate compartments are not sealed by the top at all. And if you are not careful everything will mix together. One thing that my instructions did mention was not to plug it in right after removing it from a refrigerator. It recommends to wait at least 15 min after removing from the fridge. I guess that is to prevent the PTC's from drawing a huge current trying to heat up.

Charles Bruckner

It might be useful for "baking" old audio tapes to reduce the magnetic coating coming off on the heads and rollers. Kind of small for reel-to-reel, but ought to work for cassettes.

Jonathan Hendry

Looks like there is room in the base for a small power supply and switch. Maybe mount some Peltier units to that aluminum base and use for both heating and cooling as needed?

PCB etching immediately sprang to mind. Maybe a piezoelectric air pump to get some agitation through it. Hmmm…

That's a good point. It would be ideal for that.

Big Clive

Hmm, might also make a good heater for PCB etching (once you carefully remove the middle plastic wall)