Buford (brother_buford) wrote in homebrewing,

Converting a Sanyo 4912 to be a homebrew kegerator

X-posted from my own journal, but assumed to be of interest here.

Once I had all the components necessary, it was time to take the Sanyo 4912 I recently purchased and rebuild it for its new life as a kegerator.

How I went from this:

...to a full-fledged homebrew machine was a pretty fun, if sometimes frustrating, process. It took about a day of actual work with power tools after spending all day Saturday looking for the necessary stuff I didn't have yet (wood, hole saw, etc) at Lowes.

The stock Sanyo is, as thekhameleon put it, "a pretty pimp fridge". It just has a nice look to it, and the rounded plastic top gives it a better look than the standard flat metal top you find on most mini-fridges. Its all-black interior is also a nice touch that makes it not look like a standard refrigerator. This thing is a cooling beast for a fridge, able to drop a gallon of water down to 29° F with the internal thermostat set on maximum when I tested it a few days ago. (To non US-ians not familiar with Farenheit, that's about -1.7° C.).

The stock fridge interior, with the glass shelves and crisper drawer still inside:

The first order of business was to remove the door. I had already done this once about a week ago to reverse the way the door opened due to where it would be located when finished, but now it was time to do the full-on modification. The door shelves jutted out into the fridge quite a ways when closed, and space is limited inside. In order to fit everything I wanted into the fridge those shelves had to go. They wouldn't serve much of a purpose inside a kegerator as it is, and I had no use whatsoever for the built-in can dispenser.

The foam core of the door is visible after removing the shelf panel. The rubber seal is laying across the door after removing it from the shelf panel. There were a million little screws holding that thing on.

The no longer needed shelf panel to be discarded:

The replacement for the door panel was made of a sheet of dry-erase board cut to size. It was just the right thickness to hold the door seal in place and can serve a useful purpose to keep notes inside the kegerator - what beers are on tap on the left and right sides, date the kegs were tapped, etc.). I had already drilled the board for mounting when this picture was taken.

The reassembled door:

The plastic top was held on with seven screws. The metal top of the fridge after removing the plastic cover:

One thing you have to keep in mind when planning to cut into a fridge is that the walls contain the coolant lines. If you hit one of those you have just destroyed your fridge. From what I had seen of this model, there was a coolant line that ran parallel to the back edge about 7 inches from the back across the top, but the rest of the top forward of this was safe for cutting. Wanting to double-check this, I made a thick solution of cornstarch and cheap vodka and brushed it on the top. The fridge was then plugged in and allowed to run for a few minutes. The heat from the coolant line would cause the alcohol to evaporate quicker in that area.

I waited a little too long before checking on it so I couldn't make a visual determination where the solution had dried quicker, so I brushed the cornstarch with my hand. The areas where the top were warmer brushed off as fine powder, but the rest of the not-quite-dry mixture held fast to the top. This confirmed the location of the coolant line as being where it was supposed to be. Cutting a 2 3/4" hole dead-center in the top would not cause a problem.

Now came the real grunt work. The plastic top of the fridge that had been removed was flipped over. There was an 8 inch square in the middle of the top that had plastic support fins radiating into it. As this is where the tower would be mounted, there needed to be more support. First step was removing the fins to install a support piece. The fins were scored with a utility knfe and broken off with a pair of pliers.

After the fins were completely removed:

Dropping an 8x8 inch square of 1/2 inch wood into the now cleared square. It was a perfect fit.

The wood piece was removed and a pilot hole was drilled in the center of the top outside. After replacing the wood piece and screwing the plastic top back to the fridge, it was time for the real hair-raising part - cutting the actual hole with a 2 3/4" hole saw.

Cutting the hole wasn't particulary difficult, although the drill got stuck a couple times. Cutting through the metal top was the hardest part, but after clearing that it was all insulating foam. The hole saw was removed after the auger bit cut through the plastic ceiling in the fridge, and I cut from the bottom up using that hole as a guide to avoid breaking the interior's plastic from the downward pressure and to minimize jagged edges poking out from the fridge.

The top was removed once again, and aluminum tape was affixed around and through the hole to keep foam from breaking off and falling inside and to protect the beer lines from damage.

The mounting hole locations for the tower were marked on the wood and drilled out. T-nuts were hammered into the wood to provide backing for machine screws. The wood is the support for the tower - no bolts are going through the fridge top. For this reason the screws had to be cut at the proper length to go through the nuts but not reach the metal fridge top.

I also attached metal rails to the back edge of the plastic top before re-mounting it on the fridge.

The rails can be found here: http://www.leevalley.com/hardware/page.aspx?c=2&p=46331&cat=3,43520,43521,46758&ap=1

These are the ones I used:
one 01W8316 488mm SS Bar Handle (19-7/32")
two 01W8313 232mm SS Bar Handles (9-9/64")

Silicone sealant was applied to the underside of the plastic top to provide a seal between it and the wood. Silicone was also applied to the wood before the top was reattached to the fridge. Since there is now a big hole in the top, sealant is necessary to keep cold air from leaking out and warm air from getting in.

One of the problems with some home draft systems is warm beer lines towards the tap. This leads to very foamy first pours. Beer towers are insulated, but insulation is not refrigeration. Cold air sinks, so you must have a way to recirculate that cold air to the top of the fridge and up the tower to keep the faucets and lines cold. Commercial applications and some ready-made kegerators use blowers or glycol cooling. Both are really expensive solutions, so there must be a cheaper way. The answer? A homemade blower made from a Radio Shack project box, a 12v fan, a wall power adaptor, and a piece of flexible tubing.

The project box is not airtight, but the blower just needs to be able to move some air up the tubing. It seemed to work well enough, so I didn't bother trying to seal it.

The wood to the left will be used as a shelf to hold the CO2 tank off the bottom of the fridge. As space is at a premium, raising the location allows it to sit partially on the "lip" that juts out into the bottom of the fridge over the compressor so that it sits further back.

The tower, after being mounted but before adding faucets. Note the rails on the back. I misjudged when adding the left and right rails and one sits about 1/4" ahead of the other one, but with glasses on top of the fridge it's not noticible.

A different angle of that last shot, showing the "new" door after being reattached.

The blower rests on the bottom of the fridge under the shelf. The wire to the wall outlet is run through the drain hole in the back, and the blower hose goes through a hole in the shelf up to and into the tower.

Now it came time to hook up the temperature controller. This effectively overrides the thermostat and can keep the fridge within a specified temperature range. While useful for keeping draft beer at the proper temperature, it would also be useful for fermenting lagers in the fridge when it is not being used to dispense beer.

The temperature controller's probe needs to be immersed in liquid to give a true liquid temperature reading, which is what I care about in this application. A small bottle was filled with freezer pack goop and the probe was placed in that after running it into the back of the fridge via the drain hole.

The bottle is mounted at the top of the fridge.

The finished interior, with all the gas and beer lines installed and converted to use ball-lock soda keg fittings. A loose bungee cord is wrapped around the CO2 tank and hooked to the cold plate to prevent it from tipping, although the regulator (in a cage) helps by propping against the side of the fridge. The cord is tight enough to keep the tank from tipping but is loose enough to not strain the cold plate. I just happened to have one on hand that was the right length, and there is a hole in the cold plate in just the right spot to hook the left side.

The interior, with two empty soda kegs connected.

Another shot, to give an idea of how much space there is in the fridge when full.

The drip tray and forward-sealing faucets have been added, and glasses line the back edge. I used forward-sealing faucets over standard ones as they are easier to clean and don't have the sticking and sanitation problems that standard ones have.

Another angle:

I pressure tested the kegs with a leak checking solution and they all seem to be okay, even the one with the lid that wouldn't seat before. It held pressure after I used a little silicone gel lube on the o-ring; it just needed to be able to start taking pressure long enough for the lid to seat properly. It was kind of amusing messing with the regulator and dispensing carbonated tap water - forced carbonation takes no time at all to do, as opposed to the three weeks of bottle conditioning. Only problem with that is I might get impatient and drink beer before it's truly ready.

Overall it wasn't that hard of a project, although it did take a bit of cash to get it all done. In the long run it'll be more expensive than bottling since I have to get CO2 refilled at $12.60 a refill (dextrose for bottle conditioning, on the other hand, is very cheap - about $1-2 a pound I think). The 5 lb tank should be good for 8-10 kegs though since beer is dispensed at a low pressure around 12 PSI. The convenience is much better than bottles,though - fill one container and you're done, and no measuring and boiling sugar; you also get the convenience of variable serving size and are not restricted to bottle size. Portability is lost, but I could get a growler and fill from the tap to take beer with me if it is to be consumed within several hours. If I get a counterpressure filler later I can fill bottles from the keg if I really want to.

Still, it's nice being able to look at it and say, "I made that". Homebrew kegerator for homebrew beer, taking an ordinary fridge from mundane...

To this:

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