Before gluing this and sealing the threads for final assembly it would be a good idea to blow against the flashback preventer in the direction of the arrows to be sure air passes. This way you can be sure your spring isn't too tight against the marble or ball bearing. Also if you test blow against this for a test after gluing it with PVC cement you could accidentally poison yourself. Better to test for flow before doping it up with chemicals. I used Teflon tape to seal the threads and PVC cement to glue the slip joints. Now it's done and ready to install. Just be sure to mark arrows to show direction of flow so you don't get confused and install it backwards.

I constructed this from parts I purchased at the local hardware store and from parts around my workshop. You can improvise your own design. This is how I did this and much of this can be modified in many ways. Good luck!

Previous Picture

Back to Thumbs