There just wasn't enough room to open up the IC to 1.25" without more fab\machining.
The external groove you see in the image of the expanded IC would not contain an oring as it would spill over the top and under the IC face.
The ring internal to that machined groove is actually a raised face that mates to the inner case. We removed the secondary raised ring while expanding the IC opening. Both rings effectively created the o ring enclosure as it was meant to be OEM. the rings are raised close to 1/4".
The inner case was OEM machined to create a sealable surface, but it is limited in it's width, I could not get that machined with the machinery around here.
So the plan is NPT will seal the water in the IC
A layer of RTV will be globbed on the IC's outer face, sealing against pressure leaking through the pressure side, and preventing any water leakage into the case itself.
Essentially I am making one ugly oring\gasket.between the IC face and Machined surface of the case.
There is still a oring on the fitting aswell.
But it is a not a store bought item, I had a machinist turn something I had into a fitting you see in the other image from earlier.
Plus I asssumed DOB used straight thread, but now that I know he has been using NPT I have gained more confidence in this experiment.
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