the.forumer Senior Member 415 posts Likes: 1 Joined Oct 2011 More info | Jul 13, 2013 21:20 | #1 i already have a electronic dry cabinet parked at home, but i'd love to keep things dry, even in my camera bag. was thinking of buying some silica gel when i saw a couple of options. one of it is called 'hydrosorbent' - is this any different from any other silica gel out there? or will it protect our equipment just as good?
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SkipD Cream of the Crop  20,476 posts Likes: 165 Joined Dec 2002 Location: Southeastern WI, USA More info | Jul 13, 2013 21:49 | #2 It's impossible for silica gel or any other similar product to keep the air dry in a typical camera bag. That's because water vapor in the air around the bag would replace that adsorbed by the silica gel inside the bag in very short order. The bag would have to be sealed airtight to prevent that. I have never seen an airtight camera bag. Skip Douglas
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Jul 14, 2013 08:23 | #3 SkipD wrote in post #16118034  It's impossible for silica gel or any other similar product to keep the air dry in a typical camera bag. That's because water vapor in the air around the bag would replace that adsorbed by the silica gel inside the bag in very short order. The bag would have to be sealed airtight to prevent that. I have never seen an airtight camera bag. Of course Pelican cases and their clones can be made airtight, but I don't classify them as camera "bags". If you want to use silica gel repeatedly (using it, drying it, using it again, etc.), make sure you buy the type that has a color indicator in it to show the moisture level in the product. Some products turn from blue to pink as they adsorb moisture. Others turn from orange to green. The product can typically be re-activated by heating it at 200°F for a couple of hours. that makes sense. i was reading one of the camera magazines where they recommended putting a tin can with silica gel and throwing it in the bag for good - looks like it wouldn't do very well in a non air-tight environment..
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KirkS518 Goldmember  3,983 posts Likes: 24 Joined Apr 2012 Location: Central Gulf Coast, Flori-duh More info | Jul 14, 2013 08:49 | #4 I'm not sure I totally agree with the above. Silica removes the moisture from the air, not the air. So in an airtight container, the moisture would be removed, and the air would be dry (or lower in humidity) and stay. In a non-airtight container, the initial volume of air would have the moisture removed, and as the air travels in and out of the container, the new air's moisture would be removed as well. If steroids are illegal for athletes, should PS be illegal for models?
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Jul 15, 2013 05:44 | #5 KirkS518 wrote in post #16118937 Mold/fungus need 3 things to grow: water, darkness, and air with minimal movement. Really? Frank Hollis - Retired mass spectroscopist
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Jon Cream of the Crop  69,628 posts Likes: 227 Joined Jun 2004 Location: Bethesda, MD USA More info | Jul 15, 2013 18:30 | #6 Yes, but you're in England, where the sun never sets . . . Oh, wait . . . Jon
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TeamSpeed 01010100 01010011  More info | To help with all the fungal discussions... Why does lens fungus grow? Fungal spores are everywhere and will grow whenever temperature, humidity, and nutrients exist. Ordinary house dust consists of carbohydrate (cellulose lint from fabrics) or protein (bits of you) that is fine food for fungus. Liquid water and light are not necessary. This dust typically gets pushed into the corners of a lens (ironically) from cleaning, where it collects, and these marginal heaps also tend to retain humidity. Humidity above 60 percent is reputed to be the threshold where fungal growth starts. All it takes is one spore to germinate on a single tiny lint fiber, and out go the fibrils across the glass, looking for more food. A fungal spore can feast on a tiny speck of dust for many days, covering many square millimeters of area with fibrils that will find other food present. Live fungus is basically a molecular machine that is powered by the minute chemical energy available in the dust, which dust is also digested into the substance of the fungal structure. This growth mechanism converts bits of energy-rich food into less energetic but more connected and purposed structures. The structures send forth runners (mycelium fibrils) to locate and tap more energy sources, in hopes of finding a food bonanza that will supply enough energy and material to launch baby funguses (spores) into the air, where they can travel to new, distant food sources. While the lens growth is typically not rich enough to fruit and launch spores, the resulting mycelium will degrade the lens. Besides the mechanical obstruction of the light rays the lens is designed to refract and transmit, the mycelium growth produces chemical byproducts which deter overdense growth, digest its food, and also happen to etch glass. Glass is inert and used to store strongly corrosive acids; how can fungus etch it? Glass can have a widely varied composition. The ordinary type of glass used for bottles to store acids and other corrosive chemicals is not at all the type of glass that optical lenses are made from. Microbiologists have been assuming that fungus cannot feed on glass itself, but given the variety of exotic glass recipes used in optical engineering, it may be that some types of glass provide some elements of fungal nutrition. Perhaps the etched surface is a better physical substrate which anchors or promotes growth. The highly detailed structure of the etching (as seen in the photomicrographs above) suggests that whatever metabolic product is disintegrating glass is concentrated and bound to the organism, and not some liquid that spreads indiscriminately. What can I do to avoid or stop lens fungus? Take away warmth, humidity, or the food source. Since this is not typically possible with perfect continuity, so lens fungus is simply a constant, progressive, accumulating threat. Sterilization is not typically practical and doesn't remove existing growth or prevent new growth on re-exposure. Past Equipment | My Personal Gallery
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KirkS518 Goldmember 3,983 posts Likes: 24 Joined Apr 2012 Location: Central Gulf Coast, Flori-duh More info | Jul 15, 2013 20:25 | #8 hollis_f wrote in post #16121349 Really? That would explain why a slice of bread, placed in my garden on a dry metal table, in direct sunlight, in the open (moving) air won't go mouldy. Oh, wait a moment - yes it does. What I should have said, is that light is not necessary (see post directly above this). Water is in the air, so your table may be comparatively 'dry', but the air isn't. Stagnant air is relative (mold would probably be able to grow in hurricane force winds if it could grab hold of something). And besides, bread has ingredients that contribute to, and speed up mold growth. If steroids are illegal for athletes, should PS be illegal for models?
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Jul 16, 2013 08:24 | #9 I have one of these in the main compartment of each of my bags... [6D]
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bps Cream of the Crop 7,607 posts Likes: 406 Joined Mar 2007 Location: California More info | Jul 17, 2013 15:50 | #10 w0m wrote in post #16124730 I have one of these in the main compartment of each of my bags... http://www.amazon.com …ohs_product?ie=UTF8&psc=1 Just a small tin filled with gel you can toss in the oven for an hour and dry out for reuse. It won't prevent all moisture from entering bag; but it's small, cheap and easy enough that I consider it worth doing for peace of mind if nothing else. I own these too and was fortunate enough to buy them for $3 or $4 each, but I can't remember where. I love them -- they work well and practically last forever.
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pdrober2 Goldmember  2,318 posts Joined Nov 2010 Location: Durham, NC More info | Jul 17, 2013 21:43 | #11 bps wrote in post #16129110 I own these too and was fortunate enough to buy them for $3 or $4 each, but I can't remember where. I love them -- they work well and practically last forever. For the sake of the ongoing discussion, they really aren't meant for bags that do not seal. Say for example, that you place one in a Crumpler 7 Million Dollar Home. It helps to a minor degree, but isn't really effective because air travels freely in and out of the bag as it sits there. Essentially, over the course of several days of the bag sitting there, the internal air in the bag will balance out with the humidity level of the air outside of the bag. The desiccant will too and the humidity level will simply match, inside and out. Or if the air outside the bag is really, really humid, then the desiccant will simply absorb humidity until it can't absorb any more, and then the humidity level inside the bag will continue to climb until it equalizes (and matches) with the air outside the bag. In summary, desiccant pouches or containers aren't very effective in a bag or container that doesn't seal. However, desiccant does work very well on a bag or container that does seal, such as a Pelican case. In this case, it does an excellent job at absorbing moisture and keeping the air inside dry until it fills up, or the container is opened and air that is more humid is let inside. (And then the process repeats itself.) I always keep desiccant containers in my Pelican cases. In regular bags that don't seal, I do not use them as it is mostly a waste of time. Bryan I use the same in my case, but its so damn humid here I had to start using 2 at time because they were turning so fast Fujifilm X-T1 | 23 | 27 | 56 | 90 | 55-200
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