NIKONOS O-RINGS AIN'T JUST BLACK RUBBER BANDS (PART 4)
Text and Photos by Bob Warkentin
From previous articles you should remember that (1) It's the nature of O-rings to become "tired" and flattened from doing work for you (being compressed between parts to seal out water) just like you get tired from a day of working, and (2) Greasing a "tired," flat O-ring is like greasing a bald tire; although it looks new and shiny, you still don't have any rubber left for traction on a wet road! Now, let's complete this four-part series with part four to see what O-ring grease really does.
When it comes to using your O-ring grease, have you ever said to yourself: "If a little works well, a whole lot will work even better"? If you think that, just because your grease comes in a tube like glue does, putting big gobs of grease onto your O-rings will prevent flooding (like you put on gobs of glue to be sure it holds broken parts together), you're in for a very big shock!
Well then, if grease doesn't prevent flooding, what does it really do? A simple question, to be sure. But it's difficult to answer, fully and correctly!
Surfaces of rubber have a high coefficient of friction and like to grab onto other surfaces. Therefore, your grease is scientifically formulated to be solely a surface lubricant to reduce the coefficient of friction (twisting, uneven seating, wear and abrasion) between the surfaces of rubber O-rings and the surfaces of the metal or plastic parts. For user-compressed O-rings, this surface-to-surface lubrication is required not only for opening and closing O-ring-sealed parts, but also for allowing the O-ring to uniformly equilibrate itself lengthwise when under compression. For internal movable parts like the trigger, switch knobs, film advance levers, etc., which are also O-ring-sealed, add to the above lubrication requirements operational movement (wear).
A lubricating-type grease is a viscous "gelled" material in which a liquid (oil) is usually suspended. Both the gel and its liquid are specially formulated to meet certain use requirements: temperature, separation, type of oil (the liquid), chemistry and compatibility with other substances (plastic, metal, and rubber), degradation (breakdown) products if used in the presence of substances such as salt water, etc.
But why a gel versus a liquid and on some method to transfer the liquid to where it is needed when it is needed. Think of your car's lubrication requirements: the crankcase (reservoir) filled with a liquid lubricant (oil) and a pump to transfer this liquid internally to all required locations, versus the external ball joints (no liquid reservoir), which must hold and retain lubricants using a viscous gel.
And once the O-ring's surfaces are uniformly lubricated, any more grease you apply will neither improve the O-ring's sealability nor further reduce the coefficient of friction!
Grease must be "sticky" to hold the lubricant in its required place. But this stickiness causes other problems as well, just like the underside of your car-when sand and other particles come into contact with anything greasy, they stick. In your Nikonos equipment, the sticky nature of the O-ring grease causes particles of sand, salt crystals, the lint from your towel and cotton swabs and tissues, and particles of camera case foam to become stuck to the grease and cause flooding on the next dive. It is important, therefore,for you to understand stickiness in order for you to receive its benefits without any problems.
Since the gel (grease) also has the ability to hide stuck particles and fibers from your typical "eyeballing" examination, don't get into the position of saying to yourself: "That looks good enough; let's go diving!" There's only one way to remove those particles that are stuck to the grease, hidden from your eyeball" and waiting to flood your equipment: remove the grease entirely from the O-ring, the O-ring channel, and the "fourth" wall (see previous articles) of O-ring contact.
Grease Removal for User-Serviceable O-Rings
How do you remove grease from your hands and face: by wiping them on a towel, or with soap and water and then the towel. Wiping grease off O-rings by hand (then off hands and onto a towel, repeated frequently!) may work for a while, but soap and water is the most effective way to remove all built-up grease from your O-rings (of course, you remembered to remove them from the equipment first!). Since I use a good-quality, unscented liquid soap as a mask defog, I always have a small bottle of it with me. So some for my mask, some for my O-rings! Don't wad up the O-ring or stretch it during your "washing technique." Just carefully follow the shape, going around and around the O-ring time and again with soap and water, then rinse thoroughly with water and pat dry with a light-colored towel. Just don't use something like "grandma's lye soap" or chemicals on O-rings!
Obviously, you can't use liquids or water to totally clean all those O-ring channels and their fourth walls; as the liquid flows, you lose total control of your cleaning activities, and the liquid gets into the equipment to cause damage!
The whole process of totally controlled cleaning of your equipment becomes nothing more than removal of grease by actually transferring (not smearing!) the grease, little by little, from your equipment's O-ring channels and fourth walls to your cleaning materials until the transfer (removal) is complete. Simply put, it's "mopping up"!
For "mops," light-colored, soft, nonabrasive materials like cotton swabs, tissues, even corners of towels will do. Just remember, mopping means the sticky grease must transfer to and build up on the "mop." So mop a little, go to another clean part or end of your "mop," and mop a little more, or else all you'll be doing is smearing the dirty grease everywhere!
"Mopping" requires a clean mop at all times. This means that if you use something like a cotton swab on a large surface area like the back door of a Nikonos V, use both ends of five to ten swabs or more to be sure the "transfer" is complete. Don't fall into that flood trap of using only one swab (or the same comer of a towel, etc.) round and round the O-ring channel. You only wind up smearing the old, contaminated grease back into the channel and on the fourth wall. You haven't cleaned anything, only wasted time!
Why light-colored mops and drying towels? Since all O-rings and the majority of your Nikonos equipment's O-ring channels and and walls are painted black, you can see more easily (and remove!) lint and contaminants against the black color of the O-ring channels. But for orange strobes and silver-colored cables, you'll have a problem seeing anything.
Regardless of black, orange, or silver-colored surfaces, always get yourself into the habit of using your 35mm Nikonos lens as a "microscope" to closely inspect your cleaning efforts for lint and particles after degreasing. Also inspect after regreasing and after reinstalling the O-ring into the O-ring channel. Don't just grease up and go: inspect first! Even inspect your hands and fingernails before greasing! Think about it!
Remember the 35mm `microscope" from previous articles? Look through the front of your lens one-half inch from your eye with the object one-half inch or so from the other side, and the f-stop at 2.5. It magnifies tiny particles like a jeweler's loupe!
Unfortunately, it happens over time. During your diving, washing, and rinsing of equipment, little by little you've been removing the lubricant around your internal O-rings at places like the trigger, film advance lever, switch knobs, etc. And no, you can't apply it externally from something like a spray can or grease on a tooth pick! The equipment must be taken apart, parts individually "mopped," and new O-rings installed; I suggest getting this maintenance done professionally.
Just because a grease says "contains silicone" or something like "O-ring grease" doesn't mean that the chemistry of this grease was specifically designed for use with the chemistries of your black nitrile (buna-n or NBR) rubber O-rings or the plastics and metals of your equipment! There are even some specialty grease formulations out there, designed for use only in waterfree environments, that break down in the presence of water to form acids which damage metal parts of your equipment. If you are using some grease found at your office or in your garage, you better contact the manufacturer and get the actual technical information about what the grease was formulated for and know for a fact that it is truly compatible with your rubber, metals, plastics, and use in water. If you can't find out for sure, don't use it! While you haven't experienced an "all of a sudden" flood yet, you may in time. Stick with your Nikonos O-ring Grease.
For those of you with spray cans of silicone, don't use them ever on Nikonos equipment. Read the warnings: don't use around plastics and some rubber products. And remember that the liquid spray is just that, a liquid, not a grease. It may thin or dissolve the remaining grease you have and wash it away from the O-ring! You aren't doing anything for your equipment and are running the risk of damaging it. Additionally, using a spray for some "sticky operation" problem only treats the symptom; it never corrects the problem!
True, alcohol will liquefy most gelled greases (note the words liquefy and gelled). The problem is that liquefying a gel allows it to flow easily into cracks of the equipment where mechanical and electrical parts are located, even when used on the tip of a swab. Remember total control and the discussion above of gels versus liquid lubricants. You want the lubricant not only to stay in one place to do its work, but also to stay in one place when you mop it up! So leave it gelled, and mop on!
Remember why Columbus didn't fall off the edge of the earth? He followed the contour of the planet and thus made it safely to the New World!
The majority of floods in all camera bodies occur at the main O-ring after the last cleaning! Reason: the main camera body channel is oval or sort of square with rounded comers, unlike other pieces of round equipment. In short, people forget to follow the contour of irregular channels and fourth walls during cleaning! Consequently, they "navigate" and mop the straight, flat areas effectively, but "fall off" when they reach the end of the earth and don't realize that they have pushed the dirty grease into a pile in the rounded areas of the O-ring's channel and fourth wall (causing a flood).
Ever hear someone say, "It must have leaked from the rewind O-ring" or "from the trigger or film advance O-ring"? Nope! The absolute majority of time (let's pick on Nikonos V's as an example), the leakage occurs from the upper left or upper right curves of the door O-ring. You forgot to follow the contour of both the channel and the fourth wall to remove the old, dirty grease! Simple as that, and it's your mistake and your flood.
I suggest getting the Spring '88 issue of Ocean Realm for the detailed, how-to-actually-train-yourself techniques of applying only a sufficient amount of grease to the surfaces of your O-rings. It's too long a process to repeat here.
One caution: over time, oil can separate from its gel (this is most noticeable in squeeze tubes). Therefore, the first squeeze out of either a new or an old tube should be used new lubricate your fingers (with the oil); all second and subsequent squeezes (actual oil/gel mix) are for the O-rings (a smart process even for tubs or pillbox containers).
Since grease is a surface lubricant, excessive greasing only wastes grease, cleaning supplies, and your time cleaning (mopping) up the sticky mess just to be sure you've gotten all those potential flooding particles removed while also trying to keep the grease out of areas of your equipment (shutters, electronics, optics, cables, even your film) which would result in loss of operation and expensive costs to correct.
Don't simply apply another fingerfull of grease to the surfaces of your greasy O-rings in between dives. You only force your already contaminated grease deeper into the channel and around the O-ring to cause an imperfect environment for the O-ring to try to seal against. Just apply grease to the O-ring itself, not to the channel and fourth wall! Grease on the O-ring will be transferred sufficiently to the other surface areas on closing!
Reprinted with permission from Bob Warkentin's Southern Nikonos Service Center, Inc.
9459 Kempwood, Houston, TX 77080 713/462-5436