By popular demand, I'm posting the PDF document that describes the construction of the very popular and wildly famous Son of Fermentation Chiller.  I want to give total credit to Ken Schwartz who conceived, designed, and documented this awesome piece of equipment.  I have corresponded with Ken in the past and apparently he does not homebrew any longer and the site that previously hosted this document is defunct.  I am happy to host this document for the forseeable future.

In my own brewery, I have built two chillers using these plans exactly.  They performed better than I ever hoped and I can recommend them highly for any homebrewer wishing to control fermentation temperature.

Some notes on construction:

1. Measure very carefully.  There is very little room for error on these and the more precise you are, the better everything will fit together.
   
   
2. Cut cleanly.  If you have a table saw, I would highly recommend it.  If you use a jig saw or other power saw, use a straight edge.  Do not trust your hands to cut along a sight line.
   
   
3. Read the plans completely, twice, before buying anything or attempting construction.  Understanding of how it all goes together will save you an endless amount of frustration.