Bubbling Test Tubes
(as adapted from Jim Kadel's Bubbling Tower)

Here's an inexpensive and easy way to make bubbling tubes constructed from clear plastic fluorescent lighting sleeves.   Most home improvement stores sell these for around $4, and also stock all the PVC fittings and other hardware needed for this project.

Although the plastic sleeves are strong enough to support a column of water, for their total eight foot length, it is recommend to cut them down.  Shorter tubes make them easier to handle and to store.  The bubbling tube is made to be disassembled and stored dry.  This description concludes that anyone undertaking this project has as a minimum of standard hand tools to do the job. For one bubbling tower an 18 inch square base of 5/8 inch plywood, particleboard, or flake board is sufficient to keep it upright.  You can delete the wood base if the tubes are shorter and use ta small tomato cage to hold the tubes in place as shown (without water) in the picture below .

Bubbling Tube Parts:

  • 8' plastic fluorescent light sleeve
  • glue (5 minute Epoxy and standard PVC pipe cement.)
  • 1 inch long 10 x 24 bolts and nuts (for attaching the # 3 to the wood base.)

  • #1) 1- 1 ¼" x 1 1/4 "x ½" (note configuration in photo)
    #2) 1- 1 ¼" slip to 1" threaded
    #3) 1- 1" male threaded pipe end
    #4) 1- 4" x ½" pipe (hopefully you've got some or can buy a short piece)
    #5) 1- 1/2" slip to 1/2" male threaded
    #6) 1- 1/2" threaded pipe cap
    #7) 1- 1 1/4" slip cap (Optional & not shown)

    Air Pump & Related Parts:

    For creating bubbles you'll need an aquarium air pump, some 1/4 inch, outside diameter, plastic air tubing and an air check valve. An optional part that greatly increases the quantity of bubbles, is a small "air stone". Each of these items are commonly found in the aquarium section of stores, including Wal-Mart and Kmart.

    Assembly Instructions:

    The first step is to cut the plastic sleeve to length (6 foot or less) and apply PVC cement to the inside of one of the 1 1/4" inch openings of the 1 1/4" x 1 1/4" x 1/2" fitting [ #1]. Press this fitting onto one end of the sleeve so that the sleeve is fully inserted as far as it will slide into the fitting. In a minute or two the PVC cement will set and then a small amount of 5 min epoxy cement should be mixed and used to completely seal (surround) this joint. This is important to insure a watertight connection since the plastic of the sleeve is not PVC.

    Apply PVC cement to the other 1 1/4" opening of this fitting [# 1] and fully press into the 1 1/4" slip end of the 1" female threaded fitting [# 2]

    As mentioned initially, an 18" square piece of 5/8" thick wood will serve as the base for the bubbling tube. Cut the wood to size and "x" mark its center. Then place the 1" male threaded end cap [# 3] in a vise and carefully drill two 3/16" diameter holes [for the 2 - 1" long 10 x 24 mounting bolts] along a diameter through the end cap. These holes should be near the inside edges of the cap but leave enough clearance for the nut to be attached (see photo).

    Once the end cap is drilled, place it at the center of the wood base and mark the two holes onto the wood base. Drill the two holes through the base and counter sink the floor side of the base so that the heads of the 10 x 24 bolts will recess, allowing the base to lie flat. Insert the bolts through the counter sunk holes and attach the end cap to the wood with the nuts. Holding the nuts with a needle nose pliers you can tighten the bolts fairly tight with a screwdriver from the bottom (counter sunk side) of the base. Mix a good amount of 5 minute epoxy right in the hollow of the end cap (ref. photo above), and completely cover, surround and seal, the bolts and nuts with the epoxy.

    Next cut a 4 inch long piece of 1/2" diameter PVC pipe [# 4] and drill a 1/4" hole through one wall of this pipe approximately 1" from one end. {The reason it's not drilled in the middle and that the pipe itself is a little long, is for "mistake room". There's enough room for cutting off a length of this pipe, after assembly is completed, and changing from an air stone to no stone or vice versa.} Once the 1/4" hole is drilled insert the air tubing (See photo) and air stone (optional).

    Using PVC cement, glue the end with the air tube extending [from pipe #4] into the fitting [# 1] which is already glued to the clear plastic sleeve. Cut the plastic tubing that emerges from the hole pipe to a length of 3 or 4 inches, only. With a small amount of 5 minute epoxy, seal and thoroughly cement around the hole where this plastic tube enters.

    Put PVC cement on the 1/2" slip to 1/2" male thread fitting [# 5] and insert it fully onto the open end of the 1/2" pipe [# 4]. After the epoxy has hardened around the air tube for at least an hour, attach the check valve to the short length of tubing coming out of the pipe. The check valve must be connected so that the air can flow into the pipe. Airflow direction should be marked on the valve or its package.

    Now the entire sleeve and PVC fitting assembly can be screwed onto the wood base fitting [# 3]. Use teflon plumber's tape to first wrap on the male threads of this fitting, then carefully rotate the mating fitting [# 2] of the sleeve assembly until the torque of turning is too high for further hand tightening.

    Also wrap teflon plumber's tape around the 1/2" male threads [# 5] and turn the pipe cap [# 6] until it no longer can be hand tightened. This cap will be the means by which the bubbling tube can be drained.

    This completes assembly. If you'd like to have the optional CAP [# 7] on top of your bubbling tube be sure that you drill out a 1/4" hole in the center. This provides necessary air passage both into the tube during draining, and out of the pipe during operation.


    First fill the sleeve using plain tap water to test for leaks. Pour from a gallon or half gallon container using a stepladder and funnel. Leave some room near the top of the tube for the volume of "bubble space" when the pump is turned on. After some water is in the sleeve, attach the air pump and allow it to bubble, while you pour in more water.

    Once your bubbling tube system has checked out with no leaks, it can be drained by taking off the pipe end cap.

    Note: Never try to move the tower with water still in it!

    After initial testing shows the system works satisfactorily, food coloring may be added to the water, for the final effect. Back-lighting the tube with a small spotlight type fixture will also enhance the looks of your bubbling tube.

    Schedule Page

    FFNW 2014