I was fortunate a couple of months ago to find this mobile catering cool box on a pile of rubbish destined for the tip or recycling. I checked it over and immediately thought, that could easily be turned into a nice warming cabinet. So after checking if it was ok for me to take it I grabbed it.
It’s almost perfect with only the black finish that I find slightly annoying, however it’s good points are –
The door has a rubber seal and sprung catches making it almost airtight.
Its double walled construction is filled with insulation.
It’s very light and moulded handles makes moving it easy
It has moulded shelf adjustments built in.
So once I gave it a good clean and figured out how I was going to wire it, it was reasonably straight forward thing to do.
Its relatively straightforward, a power supply via rcd plug runs to a STC 1000 all purpose temperature controller, then power feeding two 60W tube heaters. With the two shelves fitted I have estimated it can take approx 48 jars and with one shelf a single 30 lb bucket of honey and if needed a few jars of honey.
The STC 1000 was a bit tricky to work out the correct wiring but following a bit of internet digging I soon found the correct wiring diagram.
The housing for the controller is a drill box, the sort of ones that when you open the box all the drills stand up presenting themselves to you. With the rivets holding the drill cradle drilled out the drills just lifted out. I then drilled two holes and fitted two cable clamps. To strengthen the box I fitted a small piece of ply around the hole for the STC 1000. Two more smaller holes were drilled, one for an earth clamp to the metal box and another in the bottom so I could feed the temperature sensor down into the cabinet. Finally the lid was fixed in position with a self tapping screw.
I settled on two 60W tube heaters after first fitting one. Although a single tube heater was working ok I thought it was taking to long to reach 45*C. I also thought the tube was slightly too small for the space and could create uneven heat in the cabinet so I decided to fit a 2nd to see what that did. The 2nd tube made a big difference, the cabinet heats up faster and the STC controller was able to control the temperature without any problems.
I have now warmed a number of jars and four buckets of honey and it does it without any problems. Most pleasing is after warming the buckets I have tested the temperature of the honey against the set internal temperature of the cabinet. I tested the temperature of the honey in the bucket, at the bottom, side and in the centre and it’s extremely consistent reading 45*C when the set temperature was 45*C.
This consistent temperature of the honey has told me, first the bottom of the bucket is at the right distance away from the tube heaters so as not to create a hot spot on the bottom of the bucket and that the insulation of the cabinet is so good that there is a very good even heat throughout the whole cabinet.
Another experiment I did was to warm some jars of honey over night, in the morning I turned the cabinet off and eight hours later I opened the cabinet and the jars were still slightly warm showing the cabinets good insulation properties. This was also on a cold winter’s day with the cabinet in my cold unheated workshop.
It does take about 24 hours to fully warm a 30 lb bucket but also needs no attention during this time so can be left. My other system of warming a bucket is much faster but requires you to keep an eye on it. So with the two systems I have options on how to warm honey.