Verdict: Very low RH 0% to 10% will NOT dry grease or oil.
-The grease blocks on the right; one from the silica gel container and another from standard container.
-The one at the bottom is also from silica gel container but spread thinly to test if thinner coat will dry but result is the same, no drying noticed.
- The left top is engine oil, again no change.
but i still think if we want to relate ur findings to the camera oil and grease, u gotta use the real camera oil and grease to test. becoz i have the impression that their components are pretty different... but the problem is, i don't know where to get them!
cameras are not made of tofu
There is no need to drill into this low RH issue further as the oil and grease spreads across a good range of densities. From the behaviour and observation, I would say that regardless what type of grease (light or heavy) the camera manufacturers use, the outcome will be the same.
You should now be figuring out why there are some people experiencing or claiming grease drying in the mechanism? Was there camera stored in differently or buried in silica gel?
Were they referring to grinding sound they heard from plastic mount lens, if yes that's normal bec of plastic abrasion with prolong use, not the grease.
I think the problem with really low humidity levels has more to do with the rubber (grips, etc) than the grease. I personally killed a vectis weathermatic by storing it in low humidity. The rubber cracked and there was some oily residue on the rubber parts. I left it in a dry box w/o a hygrometer for >6 months so I am not sure about the specific conditions needed to dry up rubber.
I have heard few who had such encounters and I have a reason for this. Rubber that has been used for long time are degrading (regardless dry or wet),lost tension and breaking down. Like paper, rubber will also absorb and loose moisture as you use and store. When moved from a moist to dry environment for extended period, the high loose of moisture causes compaction of the rubber and hasten the crack eventually. However with mid RH, the rubber will also breakdown but turn sticky instead.
Why new rubber do not encounter this is due to the oil protection but will gradually lose with cleaning, expose to sun and perspiration. Which is why, apply wax on new rubber prolongs the livespan significantly. *BUT what is basically true about natural rubber, paper and leather is that too dry and environment will cause crack or brittle.
As previously written, when rubber, plastic touches silica gel, it will turn white, this is bec the silica absorb the surface wax on contact, resulting in permanent discoloration. This reason is why all items must be separated from touching silica gel.
Why plastic mount including interior of the lens will never outlast steel in heavy use is bec plastic is soft and flakes with abrasion even in presence of grease. The more it flakes the more the particles cause abrasion.
Those who swims in pool with watches may have encounter silicon straps turning white fast and crack. This is caused by chlorine.
Last edited by spheredome; 28th November 2009 at 11:34 AM.