O-Rings

- What o-rings will work with espresso machines?

- What materials are used and what are their respective pros and cons?

- What materials are food compatible?

- What sizes are used and are their standards?

- Where can 0-rings be purchased at a reasonable cost?

These are just some of the things I need to think about.

Some guides I came across on the Internet that I need to study:

Parker O-Ring Handbook

O-Ring Reference Guide

Dichtomatik O-Ring Handbook
(this looks very comprehensive)

Sealman's O-Ring Handbook
(another comprehensive guide)