Ok, so after seeing a lot of pictures of multi-chambered bongs I decided I wanted to make one too, and assuming other people do as well, I wanted to make an extensive how-to on them. Equipment: 1) 2 plastic bottles 2) 2 bottle caps (the ones from the bottles are fine) 3) Metal Tire Gauge (make sure it's not coated in any paint) 4) Socket that Fits in Gauge Pipe 5) Chip Clip or Black Paper Clip 6) Cap from shaving cream (I use edge) 7) Duct Tape or Electrical Tape 8) Screen or Wire Mesh Step One (Sanitation and Prep): Clean out bottles and shaving cream cap. Remove spring and nozzle from tire gauge leaving only the hollow metal rod. Clean this out as well. Step Two (Making the Stem): Put the screen in the socket and insert into the hollow rod. Put the clip on the rod and congratulations you have a stem. Set aside for now Step Three (Making the Bottom Chamber): Take the first bottle cap and cut a hole large enough to fit the stem in. Cut another hole, the same size, in the side of the bottle. The second hole should be positioned so the stem can reach the water if inserted at an angle (like any bong would be). Tape the bottle cap so that the hole on the cap is slightly higher than the hole on the bottle (this allows for the stem to stay stably at an angle into the water) See diagram below. At this point you have a pretty good bong. Load up your bowl and take a hit! Step Four (Making the percolator): Take the shaving cream cap and put it on the top of the bottle. Mark out where you can cut holes while still being able to tape the cap to the bottle and yet have the holes lower than where the water is. Now cut those holes! Cut a hole in the other bottle cap so that smoke can go through it. Screw on the bottle cap and tape the edge cap to the top of the bottle. Step Five (Making the second chamber): Cut the second bottle in half and cover the first bottle with it. Tape it off. Step Six (The Final Step): Fill the bong with water (I put a straw through the bottom hole and put it under the faucet to fill the 1st chamber, the second chamber you can just fill through the top) Fill the bowl with weed. Light up and enjoy! Substitutions for any of the items is perfectly acceptable. Make it your own.