Bulkhead gasket question

Setting up a cube I picked up used and when I tested the bulkheads, one was leaking. Removed both and they have gaskets with ridges on one side. Haven't seen these before, mine were always smooth on both, but I can't find a definitive answer as to what side goes to glass. Dan, with Avast Marine says smooth to glass, which I would think but it's about 50/50 and that post was made when Bush II was president

Second question: is there any advantage to that type of gasket, vs the double smooth sided ones I've always used in the past? Been on a 6 year tank hiatus and lots to relearn


Active member
All my bulkheads I received, the gasket was originally placed with the ribbed side going towards glass.
Smooth side on glass so it does not bind while tightening.

I would think the ridges account for any inconsistency in the surface of the molded plastic. There is sometimes a line of flash where the 2 halves of the mold meet. I always remove the mold flash with sandpaper before installing.

Glass is pretty flat. Molded plastic not so much.
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