Silica Gel Reuse

Discussion in 'Casual Photo Conversations' started by Sanford, Sep 18, 2017.

  1. Anyone see any reason not to take the silica gel packet from an empty pill bottle or shoe box etc, and toss it into your camera bag?
  2. Bake them about twice a year (while preheating for your pizza) to keep them functional.
    If you carry a bag of rice around instead you'll have a meal when you'll need one.
  3. Yes you can reactivate them by baking till the color indicators go clear, usually 135 or so. Remember they will start absorbing right away & they won't be an a sealed environment so replace or recharge regularly.
  4. Do it Sanford, if it makes you feel good. As to keeping your camera and lenses drier, I doubt if there will be any measurable help there. At least that is my experience and that of people I have worked with. Large commercial silica is a different story. But no, nothing wrong with doing that. Costs nothing. Hurts nothing.
  5. William Michael

    William Michael Moderator Staff Member

    One reason is, specifically those gel packets which are in "pill bottles" are (in some jurisdictions) subject to laws: in broad summary that is for them to be contained in what amounts to a "child proof container" or "upon opening said container to be discarded carefully".

    One's camera bag represents neither of those situations. I can envisage easily the possibility of litigation if a kid picked up and swallowed a "pill packet silica gel" that was laying in my camera bag.

    Additionally, little (i.e. small) gel packets such as those in pill bottles would not serve much purpose in what amounts to be a relatively much larger volume camera bag. Those gels sachets found in shoe boxes vary in size, at least here they do. The bigger ones would (obviously) have more clout in a camera bag, provided that you dried them out regularly.

    Note that when any gels get filled up with moisture then basically you have a lot of little bags of moisture, in your camera bag - I have no idea if the gels can get weary and subsequently that moisture can leak out - but it is a reasonable question to ponder.

    On the broader topic, I have found that "air flow" is the general key to keeping lenses and cameras in a 'dry' condition - so leaving your camera bag open (anecdotally, most people leave their gear in a closed bag) and in a room (not a cupboard) and against an internal wall which is away from the kitchen and the bathroom is my general practice rather than dumping silica gels into it. My camera 'cupboards' have always had good airflow (holes are purpose made for that airflow) and are situated as per the above description.

    That's my successful formula and generally I have always lived and worked near the ocean (walking distance or a tad farther) and whilst not tropical but certainly in relatively humid environs.

    Last edited: Sep 18, 2017
  6. PapaTango

    PapaTango Itinerant Philosopher

    I may catch flack for this, but if someone's kid chokes on something that they extracted from my camera bag--I call it karma.

    Maybe I should take the change out of my pockets lest some little tyke reach in and end up asphyxiating on a quarter or a pipe lighter...
  7. Silica gel degrades into fine, highly abrasive dust. Repeated regeneration will cause degradation. Silica gel adsorbs water to a very low level, but has very little capacity. It's main use is to scavenge moisture from sealed containers. Recall that you find them in gear wrapped tightly in plastic bags, not wrapped around cameras. If your camera bag is opened as often as mine, forget about using silica gel pouches. Sporting goods shops sell strip or tubular heaters for gun cases.

    If you live in an extremely humid environment, consider buying or constructing a dry box. It doesn't need a desiccant, just a source of heat to keep it 15 degrees or so above ambient. That lowers the relative humidity and drives moisture out of absorbent materials.

    Get a life! There must be a dozen things in a camera bag for a toddler to choke on. Coins nave an enduring fascination for them. Keep the bag zipped and put away. Once kids are over two, they lose that oral fixation.
  8. William Michael

    William Michael Moderator Staff Member

    ... no serious flak from me. (pretty sure its "flak" - maybe that's just the English spelling and the American spelling is 'flack' for both meanings - that's not a criticism, but a question)


    I am not keen on any kid choking for whatever reason.
    But I am also not keen on me being legally responsible to stop kids delving into my kit of gear and extracting stuff from it when I should have disposed of those little gel buggers "responsibly".

    But (as I think that you know), my general point was laws are laws - and law can be a funny thing that can bite one in the bum.

    Also these little points, I think, continue to provide a realization that it is not the same situation across all the places in the world where PN members live: as a few other examples I have previously used: Copyright is not necessarily automatically acquired by the Professional Wedding Photographer when the shutter is released; Return of a purchase because of change of mind, is not necessarily a Consumer's right; In some locations there is not the right of Photographers to make images of people in public places, etc.

    In any case, my view is that the little silica gels in a camera bag will do three-eighths, of two-fifths, of bugger-all. (that's Strine for "not much bloody use at all")

  9. PapaTango

    PapaTango Itinerant Philosopher

    Ed, you have it right. The capacity of these bags is limited, and does not stand the test of repeated dehydration.

    By the way, I HAVE A LIFE, thank you. I am spending much of it in here with you, darling...

    Last edited: Sep 18, 2017
  10. It is kind of baroque, the concerns about swallowing. But the wee packets does no good in open bags exposed to human breath and dog breath and what you have in your garden growing...I have seen the results of even large silica in sealed containers....beautiful mint Alpa destroyed for instance... Be smart, San, keep air circulation if it is microbials and fungi you have in mind. There are camera bugs that speciaize in gear They find lens cement tastyw a side of silica and the adhesive on leatherette absolutely scrumptuous. UV A is a great anti microbial. Bake the lenses for 20 minutes a month. It will give you more Vitamin D as well. Alooha
    Last edited: Sep 18, 2017
    William Michael likes this.
  11. Too small, wrong type and the camera bag isn't sealed well enough. I keep my stuff in a dehumidified room when not in use. My older collectible stuff (probably worth $1.98 these days) lives in a plastic storage bin in the same room with a big towel that gets dried in the dryer periodically. Seems to have worked well over the years.
  12. Thanks, LOL

    Life is too short to invent things to worry about. Leave that to the product liability and personal injury lawyers. It's not limited to children. My wife put some of those brightly colored gel-packs of dishwashing detergent in a candy jar. Almost got me ;)
  13. Truth be told, I've always wondered about why it has even fallen into common use as a dessicant.

    In the lab, we have a large choice of dessicants and many labs will even have bulk quantities of silica gel on hand. I rarely-if ever-recall anyone using it as a dessicant and that's even in an environment that's sealed pretty tightly. I'll go out on a limb and say that at least in my world, calcium sulfate is by far and away the most common dessicant and I've even gone so far as to use it to keep silica gel dry.
  14. Hello everyone. Growing up in Hawaii with it's various critters & growths, keeping cameras protected was a job. First it was white rice in a sock in the camera bag when not used, and when silica gel packets & freezer bags came upon the scene, they where welcomed. For the last 6 years or so with my "snow birding" back n forth to my Ohana in Hawaii, or here in Puget Sound, I have used the following procedure with great luck. . no fungi or corrosion of anything. Large freezer bag (1 gal), 2oz packet of silica gel, 1 cotton ball with 70% alcohol (semi dry). Into this place a camera, without lens, or a lens. Close freezer bag & put into another freezer bag. Seal's on this bag are covered with black electrical tape.
    Why is this "procedure" done on both sides of the Pacific? Puget Sound is another death trap for unused camera equipment. Cold & Wet = critters of all types !!
    When I fly back to either abode, I unwrap the cameras, fire up the oven for a pizza and re-generate the silica gel packs while warming the oven, and the next day I am back to photography. All films are popped into the freezer during any absence. Enjoy, Bill
  15. You mean calcium chloride, which has high capacity but leaves a relatively high vapor pressure. It is cheap, easily reconstituted, and amenable for use with a dye which changes from blue to pink as the desiccant is exhausted. It also sheds a lot of dust and is highly corrosive.

    Calcium sulphate sans water is called "plaster of paris," which I have never seen used as a desiccant. Calcium carbonate is used, but has both low capacity and low efficiency.

    Silica gel would remove water from Ca based desiccants, not the other way around.
  16. Norman 202

    Norman 202 i am the light

    Silica gel reuse means becoming more like the French (8)
  17. Nope, we rarely use calcium chloride. It's deliquescent, so it just tends to make a mess. Even if it doesn't absorb enough water to completely liquify, it still clumps badly. The only common application I'm aware of for it is to maintain a dry atmosphere in reaction vessel by way of a drying tube. Even doing it that way is MOSTLY for pedagogical applications(i.e. the Grignard reaction in organic teaching labs) as most research labs would prefer to use dry nitrogen or argon.

    Anhydrous calcium sulfate is sold commercially under the trade name DrieRite. It's available both in indicating form(with cobalt chloride) and non-indicating form. Again, I'll go out on a limb and say that in my corner of the world(several different institutions) it's the most common dessicant in use. It has a high dessicating capacity and can be regenerated at around 230ยบC. Usually, when I'm doing something like filling a dessicator with new Drierite, I'll mostly use the non-indicating version and sprinkle some indicating Drierite on top. Stuff that's been regenerated tends to be more evenly mixed.

    Next to that, we also use molecular sieves, although they tend to work better to dry liquids than air. They are easier to handle as their regeneration temperature is lower and are also not dusty. One notable exception I'll mention is the in-line scrubbers I use on my gas chromatographs, which use a combination of mol sieves and indicating Drierite.

    I've also been known to use more unconventional dessicants depending on the application. As an example, I've been known to use sodium metal to dry ethyl ether, although we eliminate the need to do that now by buying guaranteed anhydrous ether in Aldrich Sure-Seal bottles or equivalent.

    On the whole, though, we just don't use silica gel is a dessicant despite-as I mentioned-buying it by the kilogram. It gets used almost exclusively for chromatography applications.
  18. I've used molecular sieves to dry compressed air systems for manufacturing. They absorb water from air under pressure, and are then regenerated by discharging low pressure air through them, almost like perpetual motion, except for entropy.

    I guess I never read the label on Drierite. It's pelletized so that it has a high surface area and remains relatively dust-free. I've been away from a lab for so many years it all seems like a dream. I passed up a job on uranium enrichment to make pills and liquids for 30 years.
  19. A temperature and moisture controlled room would be ideal. Air conditioning is the ultimate anti microbial environment in Hawaii. it may be I got bum dope but I do the "baking" so to speak of lenses and some prism gadgets every so often. Funny that some never show contamination and others get fungal spots, mostly small ones. Spots on a 20 yr old lens ,I do not sweat. Fibers or tentacled spread between elements indicate a spreading of the fungi and then it might, (not must,) affect the images. A pen light examination will likely ruin your day==golly there is DUST in there-help etc etc.. I have had one lens professionally disassembled by Canon repair and cleaned and lo it now has some fuzz again in five years. To say this is a generic problem is not exaggeration. But not inevitable Some lenses remain free after 30 years. Go figure. Following a lot of years with a lot of gear, I still have not advice that I can stand firmly behind. Except, in Hawaii, it is not smart to store optics in leather or even vinyl anything. Air circulation and take the critters out for a brief direct sun bath cannot hurt.
    Last edited: Sep 21, 2017
  20. In the long term, air conditioning (humidity control) is beneficial. After an overnight soak in a cool room, it can take a long time to warm up enough to avoid condensation when you go out into the humid outdoors. When possible, I left my camera bag zipped overnight, which helped retain the heat of the previous day. My greatest fear was if condensation were to occur inside the lens, it could take a really long time to dissipate. It hasn't happened, but it could.

    I worked a couple of years in Puerto Rico, where the dew point would reach 93 degrees (6 degrees above skin temperature). I can't imagine what Hawaii would be like.

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