Mini Fridge Collar and Temp Controller Build

Hey Everyone,

I needed a fermentation chamber for a Scottish Heavy Ale I'm doing and had a 1.8 cu.ft. mini fridge that the 5 gallon carboy wouldn't quite fit in, so I decided to build a collar for it and add an "eBay Temperature Controller" while I was at it. Below are a few pics and the plans I made for anyone looking to do a similar build.

The collar is 12" deep and increased the capacity from 1.8 to 4 cu.ft., making plenty of room for the 5 gallon and another 3 gallon carboy. Not wanting to make a frame, I decided to make my own insulated structural panels using 1/2" R5 rigid insulation sandwiched between sheets of MDF I cut from a couple 2'x4'x1/4" MDF handy panels since MDF has slightly better insulating qualities. They're bonded to the insulation using Loctite Foam Insulation Adhesive and to each other using Gorilla Wood Glue. I fashioned a top brace connecting the fridge to the collar from a scrap piece of MDF and the base is supported by 3 3/4" pine boards. The outside joints are sealed with black duct tape and the inner joints with duct work foil tape.

Sorry for the mess in the picture, by the way

Along the front I lined the perimeter with a magnetic adhesive strip and covered it with black duct tape. On its own it wouldn't hold much, but with the fridge door's magnetic seal it holds it shut nice and tight.

Afterwards I purchased an STC-1000 temperature controller from eBay for $23.99 with free shipping, a 7"x5"x3" project enclosure, 8-port terminal strip (both from Radio Shack) and used a 12-gauge, 15-amp extension cord I already had. Here's the wiring diagram I made to keep everything straight:

I cannibalized the wiring I needed from the extra length on the extension cord I didn't need and the whole thing came together nicely. I only wired it for cooling, but the 8-port terminal will allow me to add on to it later as I need to:

Yes, the duct tape will be replaced with proper electrical tape very soon, ha-ha.
The temps stay steady and the refrigerator hardly runs at all thanks to the insulated collar and tight seals. I'm very happy with the way it turned out, but going metric will take some getting used to. Happy brewing, everyone!

very nicely done!

rekoob said:

very nicely done!

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Thanks! I think the total bill came in around $95, so it was a cheap project since I had a few things (like the refrigerator) on hand already.

One thing that has been useful is a radio weather station I received a few years ago as a birthday present. It has a wireless outdoor sensor that I've been keeping inside the refrigerator to monitor the ambient temperature and humidity. It also measures the temps in the room, so it's been an easy way to make sure everything is all well and good at a glance:

By magnetic tape do you mean something like this http://www.amazon.com/s/ref=nb_sb_noss_1/184-9296880-0332635?url=search-alias%3Daps&field-keywords=Magnetic+tape or http://www.homedepot.com/h_d1/N-5yc1v/R-202535615/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=Magnetic+tape&storeId=10051#.UEFY2mV5mK0?

Did you put the duct tape over the strip to help keep the magnet strip attached to the collar or was that more for looks?

Carlscan26 said:

By magnetic tape do you mean something like this http://www.amazon.com/s/ref=nb_sb_noss_1/184-9296880-0332635?url=search-alias%3Daps&field-keywords=Magnetic+tape or http://www.homedepot.com/h_d1/N-5yc1v/R-202535615/h_d2/ProductDisplay?catalogId=10053&langId=-1&keyword=Magnetic+tape&storeId=10051#.UEFY2mV5mK0?

Did you put the duct tape over the strip to help keep the magnet strip attached to the collar or was that more for looks?

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Yes, I got something almost identical to that at Home Depot in the specialty fastener section. I cut it to size (top, sides, bottom) and still have some left over, so one role should do it if your fridge is of similar size. When I made the insulated structural panels I left the insulation along the front edge recessed just enough so that the edge was flush when I applied the magnetic tape.

The adhesive on the back of the magnetic tape isn't that great, so the duct tape was both to keep it in place, improve the looks and to make it a bit more air tight when the door is closed. On its own the magnetic tape isn't too magnetic, but in combination with the magnetic door seal it held so strongly that I could stick the door to the front of the fridge without screws and it held tightly.

I've been using the whole setup for several brews now and it works like a champ. I'm able to fit both a 5 gallon and a 3 gallon carboy in it at the same time and by not cutting the plastic molded rack off the door I can turn it back into a regular bottle fridge later if I decide to build a larger fermentation chamber.

Thanks for the help!