Icenberg part 2: Upcycling a fridge to an ice cream machine
Successfully acquired a leftover fridge from fellow hacker friends, now frankensteining the thing together. Next step: Insulation.
Shopping at home depot, unfortunately they don’t have any end caps for pipes of that diameter.
So we machine one ourselves: Rough formatting a piece of PA6 plastic on the bandsaw.
Then turning it down on the lathe for a proper fit.
Old refrigerator acquired from fellow hacker friends, let’s start to rip it apart.
Surprise, mold at the top insulation. Many fridges start to build up moisture there over time when the top cover is removable – which makes sense for under-the-counter scenarios.
The polyurethane glue is nasty, one can spare to hit the Gym for a week after disassembling a well built fridge. #rawForce
It looks like it peels off easily. Which is so not true.
Slicing the insulation very thoroughly into small pieces and prying them off to not damage the cooling system.
After an hour of slicing and dicing.
The whole evaporator unit consists of glued double mild steel sheets with lots of rectangular channels.
Some hours later. That black mesh is the condenser and radiator. Thermostat hanging out to the left.
There’s a long track of evaporator tubing in the freezer compartment and only a small loop for the actual large refrigerator box.
Frame disassembled, the black thing is the compressor. The little black box contains a relais and a starting capacitor for the motor.
Two copper tubes are combined into one, here under the black gooey thing: A little capillary tube from the condenser is coaxially inserted into the backloop copper tubing coming from the evaporator.
Where the magic happens: An expansion valve. From there on the coolant starts to boil and get’s a lot cooler.
Evaporator fully extracted and ready for transplantation.
Meanwhile I finished the top cap for the ice cream container.
Due to the lack of proper insulation waterproof material for the freezing compartment I used OSB-3 (oriented strand board for interior use) for a quick mockup for now.
Expansion valve again.
Evaporator inside the wooden box.
I noticed a cold bridge at the stainless steel threaded axle which sticks out of the freezer and made this insulator out of plastic so that no metal is protruding from the freezer.
One side bored and tapped to M16 so that the axle is covered, the other side has got a smaller thread for a hex bolt.
The finished plastic insulator. Also visible: The new top lid with a small window – this is where the ice cream consistency can be probed later and where the chocolate, fruit and glitter pieces can be added just before finishing the run :-)
The hex nuts are redundant now because the plastic insulator can cover their function.
First dry run with pure water went well, but definitely lacks a proper encasing and insulation.