Silica gel

[paul owen]

This may sound a bit strange!! The other day I wondered whether storing lenses ( long term) together with a sachet of silica gel (as supplied in the boxes of mos t new lenses to absorb moisture) would have an adverse effect in as much as it m ay "dry out" the lubrication of the shutter mechanism. I thought I'd pose the qu estion to you lot!!!!! Many thanks Paul

[Richard S. Ross]

Silica gel adsorbs water vapor and is used to keep the environment dry and hence keep moisture out of the lens and shutter. If lubricated at all, shutters contain oil that will vaporize to some extent (especially at higher temperatures) and condense mostly on the inner surfaces of the lens and shutter. Silica gel would not play any role in preventing this.

[Pete Andrews]

The above is correct, Silica Gel won't absorb the lighter oils and parrafins in lubricating materials.In any case, a well designed shutter actually runs 'dry', and doesn't need lubrication. Hardened steel against brass has a naturally low friction, and it's only when a shutter has become worn that a tiny amount of light 'watchmaker's' oil or graphite needs to be used.

You should also know that Silica Gel doesn't work forever. After a few weeks at normal humidity, it becomes saturated and needs to be regenerated, otherwise it's likely to start putting moisture back into the air when the ambient humidity drops. You can regenerate it by sustained heating to over 50 Celsius, or 2 to 3 minutes on quick defrost in a microwave oven does the trick.

[paul owen]

Thanks for the replies, its amazing the info available at this site!!!! Regards Paul

[Jari Louhelainen]

I recall that Franz Lanting mentioned using frying pan for cooking and regenerating silica gel in rain forest. Microwave oven cal also be used with caution. However, keep in mind that some self-indicating varieties of silica gel may contain toxic cobalt chloride.