Quote: (Originally Posted by Scuba_Vixen)
Delrin came from McMaster Carr, it's half of a 2" thick, 4" X 12" block. All the leak points are right along the half thickness line.
Very interesting behaviour. If you were in the UK we could send you material to try out. I definitely have not seen this problem with our designs and testing recently has been to much higher pressures. This suggests it is either a design issue with your case, such as the seal or a micro crack opening under pressure, or there is some defective material around.
The points alone the thin line are very suspicious. Is there a hairline crack?
Edit: In terms of material, one of our mech guys starting early and working this weekend, has just pointed out to me there are different types of copolymer and some do leak. So if it is Delrin, then I still have the view it is very unlikely to leak, but acetyl copolymer does look and feel identical as Rob points out, and if used could be the problem.
If you try paint the inside of the casing, to see if that affects the time before you see the problem? Using paint, you put in a moisture barrier behind the KK, and can see if the water is really coming from the back and not from a spray from somewhere else.
Cheers,
Alex