the plan for this water cooling is simple. all parts are purchased from home depot. pricing in the spreadsheet reflects the prices at my local home depot, in san diego.
the water block is made from a brass door kick plate. machining can be done with a dremal tool. the layout of the pieces is shown in the sketchup files. because sketchup (to my knowledge. . .) doesn't allow small scale drawings, i used a scale of 1ft=1cm. i made the waterblock on the small side because i was worried about flexing of the material. as i'm sure you know, the main component of the brass alloy is copper, with some tin, chromium and zinc mixed in to prevent corrosion. heat transfer should be negligably different from un-alloyed copper. lapping and polishing is possible, but i didn't include it in the plans for price reasons. honestly, it would be much cheaper and easier to just buy a pre-made water block, but these plans fit with the macgyver-esqe requirements. there would be enough material left over in the plate to construct both a gpu and chipset water block, but the hardware requirements (the brass bolts to sandwich them together) would have put it over budget, again.
the pump is a simple 210 gph pond pump. the model that i found has a plastic strained basket on the inlet that can be removed to allow access to garden hose threads. the adaptor and 3/4"-thread hose barb are used on the inlet to allow attachment of the 1/2" vinyl tubing. the outlet will already accept the 1/2" hose.
the radiator is constructed from a 12" house fan and 10' of soft copper tubing. tis design mimics the homemade a/c units that have hit the make blog recently. zip ties are use to attach the tubing to the face of the fan grill.
the pump will be at the lowest point of the system, negating the need for a reservoir or priming. the outlet of the pump will go to the radiator, and from the radiator water will enter the cpu-block. from there it returns in closed loop fashion directly to the pump.
it's a very simply design, i would have liked to have included a power relay so that the pump would automagically turn on with the computer for safety reasons, but i was unable to find any type of relay at home depot.