PVC PNEUMATIC CYLINDER
(c) By: Carl Chetta 1997
Text written by: Larry Lund
This is no ordinary PVC pneumatic cylinder, this baby is
powerful! It can be made any length desired and will lift just about anything. The secret
is a readily available ram washer (Whirlpool direct drive washing machine drain hose
adapter) that really works great.
It is extremely simple and very inexpensive to make. It also can be made to
any length desired.
Carl Chetta, being the owner of "Mid-Island Appliance"
found this beauty while rummaging through his parts supply. He is always looking for
something that he could use for Halloween.
- 2" PVC SCH40 280 PSI water pipe. (White) This is the cylinder.
- 3/4" PVC SCH40 480 PSI water pipe. (White) This is the ram. If real strength is needed, use 3/4" steel pipe.
- 2" PVC end cap for top of cylinder (Drill hole in end for
3/4" pipe to fit through. See Directions below.)
- 3/4" PVC end cap for the top of the ram.
- 2" PVC end cap for bottom of cylinder.
- 1 1/2" PVC coupling.
- 3/8" x 3" brass nipple for air inlet.
- Whirlpool direct drive washing machine drain hose adapter. Part
number FSP 384496. This is a rubber piece that is bell shaped and the part number is
stamped on the bottom of the large end.
- Washing machine solenoid valve and line cord to regulate the flow of air on/off.
- Washing machine hose to connect to valve.
- Compressed air.
- PVC cement.
- Relief valve.
- Metering valve.
- Drill a hole in one of the 2" PVC end caps so that the
3/4" PVC ram will fit inside it. The piston (3/4" PVC) or ram will slide through this.
- Glue the 2" cap with the hole in it to the 2" PVC pipe. Better yet, use a couple of
small screws through the side of the end cap and into the cylinder wall to secure it. This will allow
it to be taken apart if something goes wrong.
- Once the 2" PVC cap is secured to the top of the cylinder,
drill 4 1/8" holes symetricly through the top to let air out and in when the ram is activated.
- Cut the 2" PVC to the proper length needed for your effect.
- After removing the attaching clamp from the drain hose adapter,
attach this special rubber fitting (Whirlpool direct drive washing machine drain hose
adapter) over the 3/4" PVC with the large side down. Just wrap 2 turns of electrical
tape to the small side of the fitting and the PVC pipe to hold it on. I found that the
adapter had a tendency to slip so I used 2 very small stainless pipe clamps attached together
and tightened on the small end of the bell. You must use small clamps so it does not hit the
- Slide the 3/4" PVC into the 2" PVC from the bottom and temporarily put
the 1 1/2 coupling and the 2" end cap on the bottom of the 2" cylinder. Cut the 3/4" PVC to the
proper length so that a couple of inches will be exposed when the ram is fully closed
inside the 2" PVC. Glue the 3/4" end cap on the 3/4" PVC. This will
complete the piston.
- Once you are satisfied with the fit, insert the 1 1/2" PVC coupling into the base of the 2 inch pipe and secure with PVC glue.
This stops the ram bushing from being in the way of the air inlet. Some trimming of the coupling may be
required, I just cut one in half at the seam and it fit nicely.
- Test fit everything before gluing the 2" end cap on. The
3/4" piston should extend through the 2" cylinder enough so that your working
end has something to connect to. Once you are satisfied, glue the 2" end cap on the
- Drill and thread the 2" PVC at the base to accept the
3/8" x 3" nipple. You will be drilling through the 2" PVC and the 1 1/2" coupling.
This is where the air comes in.
If you attach the drain hose adapter so that the rubber bell
shaped end extends slightly beyond the end of the 3/4" PVC it will provide a cushion
when the piston comes down. This piston will retract by gravity when in a vertical
position but some other method of retraction (springs?) must be used in other positions.
You could easily insert a spring inside to force retraction. Or mount one on the outside
from the base of the cylinder to the top of the ram. On some applications the stress on the 3/4" PVC might
be too much, just substitute 3/4" steel pipe instead. I found that using 3/4 steel pipe allowed
me to attach something on the working end. Of course you must plug the bottom of the ram so
air will be prevented from passing through. I just hand threaded a 3/4 PVC end cap onto the
ram threads and it worked fine.
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