I can't find this type where they already packet it in small plastic pack. Anyone knows where to get them in Singapore?
Please don't tell me to get the big tub from camera shops and packet it myself. I already tried that, but for all the trouble of packing it all the time, I rather get the ready made ones.
Molecular sieve have a uniform pore structure (pore sizes can vary under a manufacturing process but it is normally 4 angstroms). This enables molecular sieve to separate molecules by size. It is also non-hazardous and derived from naturally occurring materials. Usually, sieve would be used for highly demanding or critical applications. The structure of sieve provides a higher capacity for water adsorption than silica gel. It is also able to retain water capacity at higher temperatures. Because of its water retaining capacity, it is normal for it to achieve 10% relative humidity levels. Do note that sieve is the most aggressive of major dessicants in terms of adsorption rate as compared to clay and silica gel.
For example, my CCD camera sealed chamber is currently utilising molecular sieve to keep the chamber dry, and no moisture problems has surfaced ever since.
Just to mention that at such low humidity, dust will basically get struck on the lens surface due to electrostatic charges and it'll be very difficult to remove the dust and if you are not careful, it may scratch the lens surface.
For example, my CCD camera sealed chamber is currently utilising molecular sieve to keep the chamber dry, and no moisture problems has surfaced ever since.
Just wonder will it be dangerous for your CCD camera at such low humidity?? Since electrostatic charges will built up at low humidity and may "fried" your CCD camera if accidentally discharge to your CCD camera.
Have a nice day.
Yang Weixing "The universe is composed mainly of hydrogen and ignorance."
hi weixing,
am aware of electrostatic charges but do note that it is in the best scenario. to maintain 10% levels, you got to have a pretty good sealed chamber, and good sieve grades.
And will 10% relative humidity dry out the oil-spaced lenses? I know that it is generally acknowledged that the oil does not dry out for decades... but that's assuming normal storage, no?
When I got my electric dry box I set it to the minimum of 15% rel humidity. A month later, I found out that some of the stickers on my equipment started to peel off - perhaps due to drying? Now it's back to 30% rel humidity and all's well.
Cheers!
[80% Steve, 20% Alfred] ------- Probability of Clear Skies = (Age of newest equipment in days) / [(Number of observers) * (Total Aperture of all telescopes present in mm)]
btw, just in case everybody is rushing out to get sieve instead, i am not implying in my previous post that SIEVE IS THE BEST for optical applications when it comes to keeping fungus free optics. "better still" was meant in terms of water retaining capacity and I should make it clear here and now. One should go for the "normal" selica gel that everybody is using, instead of industrial grade molecular sieve if you feel that sieve is "too strong". As to why CCD chambers utilise molecular sieve instead of selica gel, it is for a different purpose - to ensure dryness in the chamber. DO take note too that nothing is perfect is the world, even if the chamber is said to be sealed by O-rings and what-nots, moisture will still creep in, perhaps in months or years, and the dessicannt has to be replaced. Sealed chambers for CCDs are probably in the region of 30-40% RH.
"The universe is composed mainly of hydrogen and ignorance." 
