Water-proofing - Advice needed

I am currently searching for ways to make the bezel of my ARC grey watertight, and have come across different materials for O-Rings and Sealants.
There are 3 different materials i can get the o-rings in :
Nitrile
Silicone
Viton
Does anyone have any experience with these, and which one would be the best for water-proofing, used in conjunction with a sealant. On a related note, what would be the best type of sealant to use? will the regular stuff used to seal baths and windows etc be good enough? or should i buy some "RTV" sealant designed for automotive/radiator applications?
Any advice would be much appreciated, this newbie needs all the help he can get, having already destroyed an ARC board/slug (and i was only taking it apart to have a look inside)
Thanks in advance everyone /ubbthreads/images/graemlins/smile.gif

Note : just in case you were wondering, im trying to make an ARC grey waterproof, and am starting on the bezel end first.

I use G-S Hypo Cement (Pinpoint Precision for Crafts, Hobbies, Watch Crystals, Optics, Industial Applications). It has a needle tip, it's water clear, doesn't fog optics, and is repairable if the need arises to remove something. You can find is at most craft and hobbie stores, watchmakers usually have it.

If you use the bath tub, and some of that other stuff, you probably won't be able to get your bezel off again. I think the idea is just to lube it with something like silicone GREASE, NOT sealer.

I would use the silicon O-ring, but NO sealant of any kind...

My experinces have taught me that using some kind of sealant will make the o-ring more likely to leak, so I just let the O-ring do its job.

CAUTION: If you use silicone o-rings do not use silicone greases at any point where they may be in continuous contact with the o-rings: Silicone grease (and many other silicone lubes) can dissolve silicone o-rings ...

I would go with the viton O ring becouse they are the most chemical resistant and you never know what you may drop your light in.

I think he means the old style Arc heads, where the bezel itself can be unscrewed into two parts.

I have two of those, and have waterproofed both. Waterproofing for these old styles are basically using a sealant of some kind (I used some sort of bathroom/tile sealant) squirted it around the optics before puting the white plastic thingie and screwing the retaining nut back on. Apply a lot so that it oozes out in the front, you can just wipe off the excess after you finish tighting the retaining nut.

The second part that I have done is put a second o-ring on the battery body, just between where the threads end and the original o-ring. This is not nessecary but I feel that it completes it.

Screwing the two piece bezel back together I didn't use anything, but just screwed them together really really tight.

So far this method has had no failures, I have put it in a sink full of water and turned the head with no water in.

Just last night and the night before I took the Arc LS, Arc LE, CMG Ultra-G into the shower with me, and all of them did not lead at all even blasting water from the shower head directly at the gap between the head/body.

Just my $0.02, hope it helps.

-YC