I PM one of the members here, with out his permission I pasted his reply below. I didn't omit his name (I hope he doesn't mind). I'm in the process of buying new O-rings to take the dimentions so next year I will know what kind and size of O-rings to buy.
Here it is:
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Thank you for trusting me with your question. I have to start off by saying that I still do not have a computer. Actually I had one of the first computers way back in the 70ties, (a Farallon) but it was recalled. So the info here is just generic. I am guessing you would like to replace the o-ring that goes on the transmitter and battery kit.
One important thing to do is to find out what size you will need. If I were a betting man, then I would guess the transmitter o-ring that fit on the threads where the transmitter screws into the fist stage will be AS568B-011 most people just use the dash number i.e. -011 when ordering an o-ring. Now, the other o-rings you need will have to be matched up, and I have no idea what size they will be so you will either have to find a chart or take them to a hardware store that sells o-rings and match them up.
For material, I prefer Viton (actually Viton is a brand name for Dupont's FKM) or EPDM. The reason I like FKM and EPDM is because they have in indefinite shelf life, so I never have to worry if I keep them too long or if someone has sent me "old stock" that is nearing it's self life date. When I order o-rings in bulk, I usually order from Orings, Inc.
oringsUSA
Go to that link and put in the dash number you want in the search box. If you just need a few o-ring, you may as well get them from a place like
Oxygen Compatible O-Rings, Lubricant and Tools - Dive Gear Express (you can also read some good info about o-rings there) and you can get oxygen compatible lube while you're at it which brings us to the next question.
Lube: You can get away using spit if you have to but if you insist on using lubricant, any kind will do unless you will be using higher concentrations of oxygen. I like to use an oxygen compatible lubricant just in case that ever becomes an issue. That way I never have to worry about cross contaminating my tools, fitting, parts etc. The most popular are O2 compatible lubes are Christolube and Tribolube71. You can find both at the Dive Gear Express site link above.
Now, for sizing. The best thing to do is actually find out the exact size or bring them in somewhere to match them up. In fact, sometimes matching up or bringing in an old o-ring can cause problems is they have stretched so bring in the component you want to fit the o-ring on to.
I hope this helps, let me know how you made out.
Couv
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Thanks again Couv!
