PaulFlat gaskets are ok at lower pressures. For higher pressures or a higher safety factor, I'd lean toward O-rings.
Flat gaskets have to to be held in place by the friction of the surfaces their clamped between. A thick gasket has quite a bit of surface area in contact with the pressure and must resist being blown out, or in when used on a sub.
An O-ring installed in a groove may have a thick cross section, but the only area that has to resist a blow out is the gap created by imperfections in the flat mating surfaces since your actually bolting metal to metal with a O-ring in a groove. This gap area is almost nothing when you have a machined cap bolted to a machined flange. The thing with an O-ring is that it must be fit into the proper size groove size for the ring your using. If you have the ability to machine the groove, an O-ring is a better bet.
Information on the proper rings and the groove design can be obtained from most O-ring manufactures. If you try your local bearing dealer, they probably can get you some literature, or at least the name of the O-rings they sell and you can contact them for literature. It doesn't matter whose O-rings you use or whose literature you get, their standard.
Don't get carried away, but if you sound like you gonna use a bunch of rings, it's more likely they'll supply the literature.
Dan H.
Paul Carr wrote:
I need some advice about what type of gasket to use. I'm builing a small aluminum pressure housing made of 6 inch pipe with flat endcaps which bolt onto welded flanges. Should i use flat gaskets or o-rings? How do i determine what gauge and type of o-rings to use and how what size of ring groove to cut? Your help would be very appreciated. pc