I own an (externally) almost-like-new 1977 USD Aquarius that has a slow leak from the 1st stage drain ports. I have overhauled the reg replacing all o-rings with 70 durometer in-spec parts. Currently, at 1500 psi (according to my trusty SeaVue gauge), I have the IP set at around 130. Still leaking.
The regulator came to me from someone who used it on an argon bottle. It had a moderate amount of verdigris on the interior (nothing on the exterior) that I initially blamed for the slow leak. This corrosion mostly came off pretty easily with a vinegar bath and ultrasonic cleaning. Ironically, the leak was slower BEFORE the cleaning and overhaul.
However, I did have to use a plastic toothbrush to really get the crusties out of the piston chamber. Even before cleaning, the chamber showed signs of both circumferential and longitudinal scratches -- although all rather light. In fact, there is only one longitudinal scratch and it is fairly close to the end cap. The chamber otherwise looks and feels completely smooth. Is it likely that these scratches are to blame, or more likely that either the piston or piston chamber is out of spec?
That's about all I know. Can anyone make suggestions as to what I might do to solve this problem? Polish chamber? Use 90 durometer o-rings? Goop up the chamber with so much silicone you could drown in it? Drive a bulldozer over it and buy an Atomic T3 Titanium Regulator?
I love this little reg, and want to use it on my pony bottle when I'm diving vintage. I suppose if it just leaks this much and no more for an hour long dive, I can cope. I'm guessing it would amount to a few full breaths of lost gas. The original piston o-ring showed no obvious signs of wear, so I'm not really concerned about the faint scratches causing a catastrophic o-ring failure.
But it is really tough on my OCD self to look down and see that constant stream of bubbles when the reg on my back is 20 years older and still leak free.
I also own a younger Aquarius (three LP ports rather than two) that I could use to troubleshoot this one, but that seems like a lot of trouble and might not tell me -- in my ignorance -- a cotton-pickin' thing.
Any takers?