NIKONOS O-RINGS AIN'T JUST BLACK RUBBER BANDS (PART 3)
Text and Photos by Bob Warkentin
There a Difference Between Frequency of Replacement for User and Internal,
Nonuser Serviceable O-Rings?
Even though both groups of O-rings are made of exactly the same rubber materials, I must say "YES". While reading through the following explanations, you must constantly keep in mind these combined factors: (1) time vs. the normal memory compression that always takes place to all O-rings (please see the previous two articles for details), (2) time vs. use and typical salt water residue buildup, and the differences between how residues interfere with each group of O-rings, and (3) time vs. effects from corrosive and abrasive residue buildup to O-rings sealed metal and plastic areas (especially the ones you can't see, nor even think of, nor can get to yourself!)
New, clean internal nonuser serviceable O-rings originally fit tightly between clean casing walls and clean movable parts (camera's trigger, strobe's on/off knob, lens' knobs) to seal out water, ÿ and only water!
Since these areas were never intended to be exposed or removed by you as part of your maintenance or your normal routine of film, lens, battery or cable changing, the actual sealing surfaces of both internal O-rings and their parts were never exposed to immediate and direct contamination during your "normal" routines. Don't be mislead by this comment; reread it again with emphasis on "immediate and direct" exposures!
But, over time, as water (salt or fresh) evaporates after every dive, permanent (can't be rinsed off, and NEVER with vinegar!) residues build up around O-rings and their sealed parts. These damaging residues are abrasive to rubber O-rings and plastic parts and corrosive to metal parts (see photo 5 below). And, through your normal repeated movement of the trigger, knobs and other O-ring sealed parts, over time you cause your neglected buildup of contaminates to wiggle and migrate themselves further down in between the water sealing surfaces of the O-ring and its part causing leakage (photo 4).
Add to this equation the effects of continuous memory compression (loss of O-ring elasticity) over time, further reducing the O-ring's resistance against wiggling of built up contaminates into that "danger zone" of flooding.
On the other hand, every time you open or remove a greasy user O-ring sealed item (camera's back door, lens, cable, battery cap), all those greasy actual sealing surfaces are without question directly and immediately exposed to contamination, be it your first or 51st dive and roll of film (there ain't no "over time" here as with internal seals; it's immediate!) Add to this the facts that (1) people generally don't know the correct ways to clean and inspect O-rings and their environments (next article), (2) tiny particles usually go unnoticed to your eye, especially when imbedded in the grease which is everywhere (but not Murphy's eye!), (3) that your user O-rings have lost some of their elasticity from memory compression and therefore do not have the strength to overcome these tiny particles nearly as well as new user O-rings MIGHT (nothing is guaranteed).
Therefore, for you "2 one week trip'ers per year" who average 10 to 15 dives per trip, the answer is "YES"! I would recommend replacing your flattened, frequently opened and exposed user O-rings every six months (before each trip), and have those internal O-ring containing parts professionally cleaned and inspected for corrosion as well as the O-rings professionally replaced and pressure tested in water every twelve months (certainly not longer than 24 months!).
But "YES" approaches "NO" if you make more diving use than closet use in the same amount of time as a "sport diver". Not only are more contaminates building up from dive after dive (see photo 3), you are also shooting more rolls and making more movements to those contaminated parts and O-rings allowing the contaminates to wiggle faster (in terms of the calendar) to the point of "leakage" (see photo 4). At the end of six months, don't just replace the user O-rings and think you've done something noble for your equipment; have professional servicing done as well. Remember, the professional must not only remove corrosive deposits from movable O-ring bearing parts and ports to prevent permanent pitting and replace these abraded internal O-rings, but also replace your user rings as well since everything must be equally water tight before it leaves the service center.
A $10 user set frequently replaced and professional servicing periodically is a wiser choice before the trip than hours spent in your room in "overkill" cleaning just to try to cheat Murphy's laws of flooding and saving a few bucks! It's a fact: over time, O-rings get flat and corrosion occurs.
I knew this question was coming, so remember this common dive trip experience! Before flying home, we give our equipment time to dry. Although the regulator's surfaces appear dry to the eye, as we turn over the second stage we notice all that water pouring out of the "dry" mouth piece and into our "dry" suitcase.
Your Nikonos equipment is no different. Although surfaces appear dry, many areas of the camera, lens, strobe and arm and cable you can't see collect and pool water requiring at least 7-10 days s to FULLY air-dry. So, when you place your still wet equipment into your camera case filled with that super-duper foam (I call it expensive kitchen sink sponge-it will "sponge up" and hold water also) and close its O-ring sealed lid, what you now have is an impact resistant "humidor".
Nikonos equipment require very large clearances between parts for safe O-ring compression (unlike land cameras which have extremely closely machined metal parts). So, if you had taken off all user O-rings and left the lens off to prevent user seal compression, without ALL holes "corked" up, what you have done is in essence no different than if you had left $1,000 worth of wine uncorked and exposed to the humidity in the air; just as good wine turns to vinegar, don't be surprised that there is rust on the shutter blades, the strobe won't power or you find fungus growing in the lens.
People, please don't try to disprove this above concept, you will ultimately lose the gamble! Each year I have to repair the damages from the same repeatedly made dumb mistakes for the same dumb reasons; this is just one of them! Profit from another's mistakes...and learn!
True, leaving user O-rings in your equipment for 6 months between dive trips means your O-rings now have a loss of O-ring elasticity, but removing them means 26 weeks worth of dampness exposure and corrosion. So, keep your equipment installed with user O-rings and a lens during "humid storage" just like "humid diving" (or see alternatives below)!
The plastic lens cap's design has camera-like cam locks to lock and stay on the lens, and an O-ring bearing surface diameter identical to the silver colored lens mount on the front of your camera for humidity control! Therefore, both result in giving exactly the same amount of compression to the lens' user O-ring. Since removing the lens from the camera and storing it with its lens cap on serves no added benefit to the lens' O-ring, yet leaves the camera exposed to humidity directly through the large lens port hole, better leave that lens on the camera. It's a fabulous O-ring sealed "cork" for your $500 bottle of camera "wine".
Oh, you've been using that thin clear plastic cap? That "cap" ain't even a cap; it's nothing more than packaging material used for shipping purposes to keep out styrofoam. Using it for humidity control is a joke! So, use ONLY your smaller 35mm or 28mm lens, NEVER one of the bigger lenses (long story why); or, see the alternatives below.
People who save used O-rings for a "rainy day" or use them for storage figuring they can remember what they did six months ago usually got them mixed up with their new O-rings. Reason: round black USED O-rings looked just like round black NEW O-rings to most people.
So, in the Spring 1989 Ocean Realm, I wrote a Workshop article entitled "CPR" (Compression Prevention to Rubber). In the article, I gave what I thought were simple steps for decreasing and banding old user O-rings LIGHTLY with a bright colored vinyl dye so you could more easily identify "storage only" O-rings and prevent confusion. Well, you wouldn't believe the problems people had and the calls I answered because I refuse to use specific product names in these articles. If you don't want to use the dye method, there are others.
Degrease thoroughly your old user O-rings, and using at least 80 grit (very coarse) sand paper, on the bigger O-rings sand heavy marks about 1/2 inch in length at 1 inch intervals on only the outside shinny edge of the O-ring (the edge you see when the O-ring is installed into its channel); correspondingly smaller marks and intervals on the smaller seals. Then, grease the O-ring as usual and try recognizing it; if not deep enough sanding marks to easily recognize through the grease, degrease and start over again. If you still can't easily tell through the grease which are which, there is now a specialty kit available containing bright orange, fully color impregnated rubber "Nikonos storage only" user O-rings for all types of your Nikonos equipment. The kit can also eliminate other storage confusion problems as well.
If you really don't want to use your lens, there are available solid plastic camera body caps designed with their own O-ring to be effective alternatives for humidity control. Be sure that the "cork" you select provides a cam-lock capability (similar to that of your own lens) to positively lock onto the camera and not fall off from bumping or changes in aircraft pressures.
DO NOT USE PACKETS OF SILICA GEL PLACED INSIDE OR AROUND PARTS OF YOUR EQUIPMENT OR CASE AS PROTECTION AGAINST HUMIDITY!
These packets are usually used when you get them from various sources, and the packet itself can tear allowing its granulated contents to spill and scratch optics, damage shutter operations, etc. Besides, to remain effective, they must be baked at a very low heat in an oven frequently just to get rid of the moisture they contain!
Remember that as your internal O-rings get contaminated dive after dive, your equipment's water proof outer casing is also being exposed to the build up of very corrosive materials. And, your camera's outer metal casing, when damaged, costs far more to replace than that of the all the shutters, electronics, etc. combined! So, don't just limit your casing inspection to the hopes of finding "that sign" that you must now spend additional money to have those internal O-rings and parts you can' t see professionally serviced; remember that, over time and use, all can not remain clean in "Nikonos Land".
Give equal mental consideration to the need for removal of hidden corrosive and abrasive salt water residues. Pitting is permanent loss of case metal; abrasion is permanent loss of case plastic. And, no service facility can drain the ocean to recover your lost metal ions or pieces of plastic nor replace them! Since the internal O-ring ports and their operational parts of the equipment's casing must also be cleaned and inspected along with O-ring replacement, your professional Nikonos service facility should provide you some guidance as it pertains specifically to its condition and your usage to help you extend its useful life.
Above all, quit thinking of your Nikonos equipment as "camera gear" in the land-camera sense. It is underwater photographic equipment in the same sense as your underwater "May West" (B.C.) and your underwater air supply system (regulator); in short, it is just another part of your "dive gear" and you MUST give it the same understanding and maintenance as EVERY other part of your DIVE equipment. It must be professionally serviced for exactly the same reasons: to stop corrosion of parts and replace O-rings to maintain good working condition for continued use in the harsh salt water environment. True, it won't kill you like other dive gear problems will, but you'll feel like it has! So, when it's time to service your regulator (yearly!), it's time to service your Nikonos!
Reprinted with permission from Bob Warkentin's Southern Nikonos Service Center, Inc.
9459 Kempwood, Houston, TX 77080 713/462-5436