This project has been sort of an evolution. It actually started as a way for me to make a sweet sparkling cider for SWMBO. I picked up one of the Home Draft kegs and force carbonated my cider using a carbonator cap I made. I then was able to use the tap for serving.
I then decided it would be a good way to "Keg" and serve my beer. I have been bottling since 1994. I have never really had an issue bottling, so I never saw a reason to go to the expense kegging although I did pick up 4 pin lock cornies recently. I also have never really had enough extra space for a full sized refrigerator until we bought our new home last year.
Anyway, on to the details. I now have 4 of the Home Draft kegs. I did not want to modify the tap assembly because I wanted to be able to continue using the 16 gram CO2 cartridges. I decided to modify the CO2 cartridges by drilling and tapping with 1/4 NPT so I could put an air chuck into them. Teflon tape does not work as a seal since the cartridge wall is so thin so I used a 2 part 5 minute "Epoxy" when installing the connector into the cartridge.
As a result of the size of the adaptor I had to enlarge the opening at the end of the plastic cartridge holder. I used a dermal but the same thing can be accomplished with a large enough drill bit. This allows me to continue using the 16 gram CO2 cartridge. Parties are much easier now that I don't have to worry about mixing sediment in bottles on the drive.
I found a Haier 4.6 CF mini fridge on blowout at Ultimate Electronics for $79. I had been keeping an eye on craigslist for a while and most people in the Denver area were asking for around $65. Wal Mart has the same model for $149.
I picked up several brass air disconnects both male and female, 1/4 barb adaptors along with a 3 way manifold and 1/4 ID poly air line. I decided to go with the poly line instead of the nylon line because 1) it is rated to 150 lb instead of 60 lb and 2) it is a stiffer material not requiring hose clamps. Harbor freight had a deal on the 3 way manifold and 3 of the female disconnects for about $9. They have a 4 way manifold online for a similar price but the store was out of stock and were not getting any more. Altogether the hardware was less than $30.
I got a used 5 lb steel tank along with dual gauge regulator, picnic tap and 2 ball lock disconnects for $90 including shipping when I was working on the original cider project.
The only modification I had to make to the fridge was to drill a 3/8th hole in the back for the CO2 line.
In my experimenting with the Home Draft system I have determined that the built in regulator is set to about 17-18 psi. This seems to agree with the CO2 chart which indicates that an American Light Lager would take about 17 psi CO2 at about 35 degrees F. So, although you can pressurize anything lower than that you can't go any higher. As a result I still use the carbonator caps I made so I can force carbonate at 30 psi (fill and shake method).
So far I have "kegged" 3 batches of cider and one batch of beer. I currently make 3 gallon batches so I use 2 kegs per batch. With my current setup I am no longer tempted to find a larger fridge and start using my 5 gallon cornies. I may have 4 pin lock kegs for sale at some point in time…