BUILDING A SINK TRAP
If you work with clay a lot, you should use a sink trap. This collects the clay that you put down the drain, preventing it from clogging your pipes. You can make one yourself from common parts. This article has appeared in numerous places, but originated at Ceramics Monthly.The materials you'll need:
a 5 gallon plastic bucket with lid (available from restaurants, etc...)
a 2 1/2 gallon plastic bucket with lid
large mesh screen cut in a circle with a diameter of the 2 1/2 gallon bucket
2 old kiln posts
a 1 1/2" metal drain pipe 6 to 8 inches long
an A.B.S. plastic "P" trap with an ABS elbow attached to either side
ABS nuts and fittings
ABS pipe cement
Take the smaller bucket and drill three rows of 1/2" holes right under the last set of ridges at the top of the bucket. Place the two old kiln posts inside the larger bucket. Place the smaller bucket in the larger bucket.
Cut holes in both bucket lids, using an X-acto knife. Make the diameter of these openings slightly smaller that the 1 1/2" metal drain pipe. Force the drain pipe through the big bucket lid, then the smaller bucket lid.
Attach the large mesh screen to the drain pipe an inch or two shy of the bottom of the pipe (Ric Swenson doesn't say how). The smaller bucket lid is now between the large bucket lid and the mesh screen.
Place the "P" trap and its 2 elbows on the pipe that joins the sewer line. The nut that joins the "P" trap and the elbow that will feed into the large bucket GETS NO CEMENT. It will become one of two disassembly nuts. The other disassembly nut is the nut that joins the metal pipe to the sink.
Cut a hole in the side of the large bucket at the height of the three rows of holes in the smaller bucket. Using an X-acto knife, make the hole slightly smaller than the elbow pipe coming from the "P" trap, which is forced through the hole. Use flexible joint compound to seal an ABS nut on the inside of the large bucket and tighten it on its fitting on the outside of the bucket. Use the compound to seal on both sides of the bucket walls. Disassemble the large bucket from the "P" trap using the nut that joins the "P" trap to its inside elbow.
Now place the 1 1/2" pipe on the two buckets making sure that the mesh screen falls well below the three rows of holes in the smaller bucket. Attach the lids to each bucket. Fit the trap under the sink by attaching the top of the metal pipe to the sink (you can use pipe tape to seal -- do not use cement) and reattaching the elbow to the "P" trap. Apply ABS pipe cement to all permanent connections.
"Check to see that the exit speed of water through the trap will exceed the volume produced by the tap(s), and that pipe placement and diameter are sufficient to accept an exit flow from a sink full of water."
"Finally, leave space between the bottom of the sink and the top of the bucket sufficient for a pipe wrench to fit. The trap should be emptied periodically, and the materials it contains may be discarded or recycled."
Now, you're are surely asking what does the bucket sit on, since it's too short to reach the floor. One solution is to use a system of plywood shelves. Another option is cement blocks and bricks to adjust the bucket's height to the ABS pipe.
p.s. You don't NEED to put clay down your sink. Many studios do not use running water at all. I now always rinse things off in a bucket of water, not under running water. That water, plus all my throwing water, gets added to my bucket of clay being recycled. It evaporates off as fast as I create it. But others store the water in large tubs, and use the top of the water (after the clay settles out) in glazes.
UPDATE: NOW YOU CAN BUY A GLECO TRAP AND AVOID THE HASSLE OF MAKING YOUR OWN!