Elastomer seals are unlike any other materials that design engineers confront. Metal or plastic parts, for instance, are probably failing if visibly distorted. Seals deform into leak paths to function properly. In most applications, o-rings are installed with preset squeeze and stretch as correct design intent.
Recently, one of our customers contacted us about a problem she was having with an O-Ring that sits on a siphon neck of a liquid nitrogen dewar. Here's what we did to help her.