Step 3: Build The Pressure Chamber
The pressure chamber is assembled first. It should be allowed to cure a full 24 hours before applying pressure. PVC pipe assembly is simple and is covered in other instructables as well as on youtube. A brief refresher on solvent welding PVC pipe. Use in a well ventilated area, make sure both pieces to be assembled are clean and free of burs, prime both pieces, put glue on both pieces, assemble with a twisting motion and hold for 15 seconds. For brevity's sake, solvent welding will be referred to as "gluing" PVC. The video shows how all the parts are assembled, make sure you have youtube annotation turned on.
Pressure chamber supplies
1 1" MPT (Male Pipe Thread) to 1" slip street elbow
1 1" elbow
1 2" to 1" reducer bushing
1 2" cap
1 2" coupler
1 foot of 1" pipe
Minimum 9" length of 2" pipe
1 valve stem
PVC primer and cement
Drill and 7/16" bit (or 5/8" if you purchased the larger base valve stem)
optional 1 pressure gauge
- Drill the correct size hole in the center of the 2" cap. 7/16" for the smaller (.453" base) valve stem, or 5/8" for the larger (.625" base) valve stem. Pull the valve stem through this hole.
- Cut a length of 2" pipe at least 9" long. Keep in mind that the longer it is the more time it will take to fill up if you are using a manual air pump.
- Glue the 2" to 1" reducing bushing into the 2" coupler
- Glue the 2" cap with tire valve to one end of 2" pipe. Glue the coupler to the other end.
- Glue a short piece of 1" pipe into the bushing, glue the 1" slip elbow onto that.
- Cut a piece of 1" pipe for the pistol grip, something between 3" and 6" should work. Glue the 1" MPT street elbow to one end of pistol grip pipe.
- Glue assembled pistol grip pipe into 1" slip elbow on pressure chamber. Ensure that the threaded fitting aligns with the axis of the pressure chamber and doesn't point off to the right or left.
- Optional: Drill a hole of slightly smaller diameter than the fitting of the air valve, locate the hole 3/4" into the pipe side (NOT the bushing side) of the 2" coupler. Use the air valve to cut threads into the hole, then thread back in using thread locker on the fitting.