I need to make a piston seal a tube that has an inside diameter of 7/8. The piston will be taking on a pressure of around 150psi-250psi. I have an easy access to Lowe's. Is there anything I can pick up there that will allowing me to make such a piston seal? I think maybe a nylon cylinder would work the best but I believe. They only have Nylon spacers at Lowe's and the sizes are limited such as 3/4 o.d. nylon space and 1 Inch nylon spacer. Is there a hardware store that sells nylon cylinders(not spacers) with an outside diameter a little to what I need? What size would you recommend and what size # of o-ring?