As the second part of my DIY blaster project, I made a working air pump that can efficiently pressurize the tank of your choice. The pictures are lacking; however, the construction is relatively simple.
- 1/2" OD tubing for pump shaft (aluminum round, 3/8" CTS copper tubing, 1/2" brass - the first two are the cheapest options)
- 1/2" CPVC rings (with an ID under 1/2", they do not slide easily on the 1/2" OD tubing. Which is ideal)
- 1/2" ID, 11/16" OD rubber o-rings
- 3/8" CTS copper tubing cap
- Vinyl tubing - 3/8" OD x 1/4" ID, and 1/4" OD
- Tiny spring (<1/4" OD)
- 3/16" ball bearing
- Make a rough check valve by placing your spring and ball bearing in the 3/8" vinyl tubing, and gluing 1/4" OD vinyl on either side. A tight fit against the spring and bearing is not needed.
- Goop the check valve within the end of your pump shaft, with the ball bearing side AWAY from where your pump head will be.
- Use a drill bit to put a hole in the middle of your copper cap.
- Use goop or other strong adhesive to cap your tubing with the copper cap.
- Slide one CPVC ring around the tube, up to the cap. Follow with two o-rings and the second CPVC ring.
- Test your fit in the pump tube; either SDR 13.5 1/2" PVC or 3/4" CPVC. Since the ID of plastic pipe can vary, you'll have to experiment a little.
- If the fit is too loose, push the second CPVC ring up slightly more - in effect, squeezing the orings.
- Roll he o-rings off, then spread a thin layer of goop on either side on the second CPVC ring to secure it in place. Replace o-rings after the adhesive cures.
I will update these instructions over the holiday weekend, but they should give a good idea of the process.
One last note: if you skip the steps involving the check valve and drilling the hole in the cap, you can use your pump for water instead. Just a side benefit for those who like making homemade Super Soakers!
Edited by Aeromech, 23 November 2015 - 07:45 AM.