Enclosure Seal Design foam vs rubber

[ErnestB88]

Greetings all,
This will seem somewhat trivial to some but this is my first attempt at designing a sealed enclosure and it seems so simple yet very easy to make mistakes.

I am designing a sealed, extruded aluminum enclosure. The ends will be sealed with metal end plates which will clamp down on a gasket (Gaskets will be Nitrile/Buna-N). The extrusion profile is square and the gaskets/endcaps will be square to match then bolted in place at the four corners. It also has to be UL approved if that makes a difference.

My dilemma is in whether or not to use foam or rubber gasket material. The ends of the extrusion may not be cut perfectly so I was thinking a foam would be more apt to conforming to the imperfect surface but a more typical rubber seal seems like it would be more robust.

Can anyone explain the difference/advantages/disadvantages to foam versus hard rubber gaskets? As I said, this is somewhat new territory for me.

 

[Compositepro]

Foam is more compliant so it is useful for conforming to to irregular surfaces. But, compliant means it deforms with little pressure. That means it can only be used for low pressure seals. dripping rain is low pressure. Water blast from a hose is high pressure. High pressure solid rubber seals use small contact areas. Examples are o-rings, or metal lips pressed into a wider rubber strip (like ammo boxes).