O Rings and General Gear Care

There seem to be a few not particularly sure of what they should do when handling O Rings and so I've developed a "bit of a paper" on this, and associated, stuff.

MISCONCEPTIONS:

* Just because you screw something protected by an O Ring into something else, it doesn't follow that the harder you screw it in the better. In fact far from it, a gentle nip will suffice, just to stop it from being unthreaded by fingers. It's the O Ring and only that which provides the integrity of the seal, not the screw, clamp, whatever.
* Cheap O Rings are just as good as expensive ones. Hello? Just how valuable is your life to you? How often do you want to replace that expensive camera/strobe/torch? Moreover, O Rings are about the cheapest thing that you can buy for the u/w diving environment, especially when compared to the cost of the device drowning.
* Never, as in never ever, use those blowers that you can get for Scuba tanks as an attachment to the BC feed hose, they're way too powerful and are just as likely to blow stuff exactly where you don't want it. They're often available at the camera cleaning stations on liveaboards. Please people, they're the work of the devil, you just don't need something that powerful.

NON STANDARD TECHNICAL EQUIPMENT:

* a magnifying glass, preferably a powerful loupe such as jewellers use. Printer's Supplies companies have lots and that is probably the cheapest way of getting them. Be polite, they usually only supply printers but I'm sure they can be persuaded occasionally to make an exception. 8x is quite acceptable; I have (because I can) up to 40x, which is somewhat over-the-top.
* a blower, available from any half way decent camera store. Forget the itty bitty brush thingie that might be an attachment for it - use it nude. Cheap, in this case, is just as good as expensive.

WHAT IS AN O RING? WHAT IS GREASE?

It's a round (well, mostly), rubberlike, ring which (in our case) keeps air in and water out. In some instances it also keeps air in and air out, as in the hoses mounted to first stages. It usually sits in a groove and is squished against an adjacent wall when under pressure. O rings can be sedentary (on hoses mounted to the first stage for example) or they can guard the integrity of something that actively moves, such as a shutter button on a camera or a switch on a torch. As a general rule sedentary O Rings can be left severely alone until the next time you need to disassemble that particular bit of kit.

The above applies to most O Rings however "captured" O Rings, the O Ring at the end of your DIN 1st stage is such a captured O Ring, work much better because they have almost zero chance of escaping. Not so, in particular, the O Ring on an A Clamp 1st Stage.

They can be made from a number of materials, the important one of which, for our purposes, is silicone. You can get silicone O Rings as well as silicone grease and the two do not get on. You can use silicone grease on anything other than a silicone O Ring because silicone O Rings will ingest that grease and swell, usually with catastrophic consequences. Silicone O Rings can be found in cameras (Nikonos, Motormarine, Sea & Sea) but I doubt that you'd ever find them in 1st and 2nd stages for example. Of the other materials I am a fan of viton - will take any grease thrown at it and is as bullet proof as it gets. Thank you very much Mr du Pont for this material.

As for grease, I personally only use it on O Rings which need to move (non-sedentary ones as described above) because grease does not affect the integrity of the seal, it merely allows the O Ring to move freely; it's the O Ring and that alone which provides the seal. Others might beg to differ but in many years of caring for torches, cameras and strobes I have found this to be sensible. Grease, of itself, attracts dirt whereas a clean O Ring will repel dirt and that's no bad thing in the u/w environment.

O Rings can and do have different hardnesses (technically called shore). Again as a general rule the harder the O Ring the better (for our purposes) because the less squished it will get under compression/pressure but the tradeoff is that it will also be that much harder to get into place. The camera back O Ring on my late Nikonos RS AF was silicone based and I hated it with a passion because such O Rings also get seriously electro magnetically charged - I would wipe it down, put it into a sunbeam and watch every piece of dust on the planet zap towards it at light speed. Then my favourite u/w housing manufacturer (SeaCam since you asked - their housings are not only exotic and superbly designed but also very expensive) decided to manufacture this O Ring in viton, because they could, but apologised that the shore was significantly harder. Never had a problem with it, loved it to little bits. I am still faintly astonished that SeaCam should have made these special O Rings for a direct competitor's system but I will always be grateful to them for it.

Where do you get them? If you only want one, go to your local Dive Store. If you're putting a repair kit together, go to your local trade store (usually) with samples and they will ever so carefully measure them (they have the appropriate equipment) and give you exact replicas for considerably less sums than your LDS or, for that matter, the provider of that particular bit of kit.

MAINTENANCE:

I'd be a millionaire if I'd got a dollar for every time I've read, seen or heard of a particularly stupid way to care for an O Ring. Amongst these are:

* Use an O Ring pick. Sooner or later you will kill it, quite possibly also the thing it's designed to protect and perhaps also the O Ring channel. Sharp objects and O rings and their grooves do not get on. At all! This particularly applies to O Ring channels which have been treated with teflon, something that manufacturers are (quite rightly) tending to do increasingly often. A teflon treated O Ring channel does not require O Ring grease.
* Replace O Rings every time you service them. That's just silly. There are O Rings which have been doing their job for decades without care or maintenance. Think plumbing. Having said that, if in doubt change it for a new one. U/w cheap insurance will never be cheaper than that.
* More grease is better than less grease. Absolutely not! Grease allows an O Ring to move without jagging, it also attracts dirt which sticks to it. If you have globules of grease sticking out of the O Ring channel chances are that significantly more dirt will attract to that O Ring. You should not be able to see ANY globules of grease on an O Ring under the loupe. If you do, you've used too much, way too much, go back and start again.
* Sea salt is not a problem. Wrong! Dried sea salt translates into salt crystals which are sharp and, moreover, don't dissolve easily. You should, especially in a hot environment, take an old sopping wet, well washed (the lint factor), towel to cover your camera system, especially so on the way back. Doesn't matter which type as long as it's water. Remember to "refresh" the towel frequently during the trip if it is a long one. As well it tends to keep your system cooler. Do it whether your system is in the shade, or not.

The best thing to use to handle O Rings is your hands. You will be able to remove most O Rings simply with your thumb and forefinger. Grasp the O Ring on each side at its broadest point and now push forward. Provided your fingers don't slip (think grease) the O Ring will create a loop forward, now peel it off. If your fingers slip, use a cloth (see below) between fingers and O Ring.

Some O Rings are in a position where the above method doesn't work. In those cases the careful use of the corner of a credit card, or similar, just make sure that it cannot cut/damage, will get it off. Have regard also to the channel, something that might be benign for the O Ring could well damage its channel. If you've just cut your fingernails, beware, unless you've also sanded them down.

Lint and similar (eg hair) is sudden death to any O Ring, so can be foreign matter floating in the air. Given that there is no such thing as "lint free" you can buy "lint free" cloths in such places as chemists, but why bother when you can get exactly the same thing (although it doesn't look so pretty) at your local printer? All printers buy "lint free" cloths by the sackfulls and in their case they're used to wash down the presses. They happen to be old sheets, shirts etc which have been well washed. So go and ask nicely and they'll probably give you some for nix. Nix is lots better than pretty.

So here you are, about to service your first O Ring. It doesn't matter, BTW, whether that is an O Ring on your hugely expensive camera housing or your equally hugely expensive first stage. Get it wrong in either instance and the device can drown. In the first case it can drown your hugely expensive camera lurking in that housing. In the second case it can drown you. So pay attention!

It's simple really, O Rings are deceptively simple devices. Firstly carefully wash your hands, up to and including the wrist (I go to the elbow, particularly in sweaty conditions). Bear in mind that your sweat glands, all located other than on the backs of your hands/fingers, could interfere with the transfer of oils, grease is oil, it's no big deal but keep it in mind. Given that you have a very clean surface to place things on, a non absorbent one such as stainless steel or kitchen benches, carefully wiped down, is good, remove the O Ring as previously described and lay it down in what will become your "dirty" area.

If I am now entirely or partially disassembling a particular piece of equipment I would disassemble in "exploded" form such that every piece follows, geographically, every other piece, also onto that "dirty" area. That sure saves scratching your head and scrabbling around for the manual that you are unlikely to have when you don't know where a particular bit goes. Now, of course, you start at the beginning to clean these bits and continue until you reach the other end. Each bit goes onto a previously designated "clean" space, in the same order as you disassembled it.

CLEANING:

Lint free cloth is good, but it doesn't necessarily do the job very well in O Ring channels. There I tend to do the initial cleaning using cotton buds, available at any chemist. Careful: cotton buds leave nasty bits of cotton behind, they're good for removing layers of grease but something is required to remove the bits of cotton. Do make sure that you use (and discard) them lavishly to get as much out as possible, they're cheap - compared to a flood. Enter the makeup applicator (double ended, the tips are made of fine neoprene and it looks and is sized just like a cotton bud except that the cotton has been replaced by neoprene) that the girls know and love, also available at the chemist. Use this to channel out any remaining bits in the groove, then inspect it carefully through your loupe.

I've received the odd look when going to get the odd packet of makeup applicators.

O Rings: wipe it down with your trusty "lint free" cloth, very carefully. Having looked at it through the loupe (every which way), turn it "inside out" so that it does not develop a memory, grease it very lightly (if you must - see above) and return it to its (previously carefully cleaned) channel. O Rings are the last thing to be cleaned, the recipient device the first.

If you have now collected some freefloating dust on that O Ring, you can get rid of it with a camera blower. Do not use your mouth, it's guarranteed that the O Ring will then collect spittle.

Other surfaces: "lint free" cloth rules, OK! Well, most of the time. Use it lavishly and lavishly discard it - there's nothing worse than applying previously cleaned off dirt onto whatever you're now trying to clean. Be generous in the use of the Loupe, that Loupe is, but absolutely, your best friend.

All of the above may sound complicated to some - it really isn't, it's just common sense. If you follow these steps you will largely avoid O Ring problems. Having said that, have I had a drowned camera? Of course I have - and not just once, moreover it was my fault all but one time.

GENERALISATIONS:

Whatever it is that you are attending to, it is either a life saving device (1st/2nd stages) or an attendant life saving device (such as a torch) or a piece of rather expensive equipment that you'd rather not see drown (such as a camera/strobe). Giving them the care and attention that they deserve will minimise, but certainly not eliminate, equipment problems.

Always remember that the only time that you are positively, absolutely, guaranteed a 100% waterproof seal of your system is when all the planets are in alignment at exactly the same time that there is a wholly visible blue moon in your particular part of your hemisphere of this small planet.