What i suggest you do if you do is to go to a hardware store (like ace or macs) and bring a sample of 1" pvc with you to find the right O ring.
a method i found to work nicely is to turn down 1/8 polycarbonate circles mounted on the drill press. I clamped a piece of wood down on the table and then just turned it down with a chisel like it was a wood lathe. then just fine tune it until everything fits perfectly sandwich the 3 pieces together and put ur O ring in between.
i used this for a seal in 3/4 schedule 40 pvc and it sealed up really well.
Best of luck