Bulkhead Fitting Gaskets Question

pchromis

pchromis

Member
I have Schedule 80 bulkhead fittings that came with my tank 1" and 1 1/2".
I have a question about the gaskets....They each have on one side of them slighty raised ridges and the opposite side is completely flat.
This is my first drilled tank and not sure which side faces the glass.
Thanks
 
posiden

posiden

Active Member

I have always put the ridges towards the sealing surface, ie.....glass, plastic what ever I am using them on.
 
bmkj02

bmkj02

Member
Same here. I have used the ridge side on the glass. Mix review on this but I havent seen SCSInet go wrong yet so I will guess Im wrong
 
scsinet

scsinet

Active Member
IMO, the glass is far more likely to be a true flat surface - hence a better sealing surface - than the lip of the bulkhead which is just a piece of injection molded plastic.
When you imagine a gasket compressing, the ridges would cause the pressure to be concentrated on a smaller area, causing the gasket to "mush" better against the surface. This, in my mind, would mean a better seal against a potentially less-than-perfect surface, like the bulkhead.
In the end though, we've got a couple people here who say one way and a couple others that say the other way. Nobody though is saying anything about any leaks, and most bulkheads I've seen don't have any ridges on their gaskets. So... it seems like it doesn't matter much.
If you are worried about it, spread a thin layer of silicon on both sides of the gasket and it'll never leak.
 
posiden

posiden

Active Member
Originally Posted by SCSInet
http:///forum/post/3138843
IMO, the glass is far more likely to be a true flat surface - hence a better sealing surface - than the lip of the bulkhead which is just a piece of injection molded plastic.
When you imagine a gasket compressing, the ridges would cause the pressure to be concentrated on a smaller area, causing the gasket to "mush" better against the surface. This, in my mind, would mean a better seal against a potentially less-than-perfect surface, like the bulkhead.

This is why I put the ridges against the glass. The glass,a better sealing surface for the thinner sealing parts of a gasket. The injection molded plastic will press into a flat piece of rubber creating its own pressure points without having to fight with ridges.
As you say though, No one has complained of leaks.
 
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