Desiccation crystals

[dm_td5]

I need to get some more crystals to store with equipment. I'll have to order them in if I buy the "correct" photo equipment type and this got me thinking - which is always fraught with danger.

Why not just use that "Crystal Silica" cat litter that they sell in Woolies?

I'm assuming it's the same and is obviously designed to absorb moisture. I can buy it in town and so it's available easily.

Has anyone tried this option?


And before anyone asks... no I'm not going to recycle the cat box into the camera gear

[Raskill]

Given the weather you've got in the top end just, I'd buy a boat.

You can buy the 'proper' ones on ebay, for storing in with your gear in pelican cases. I have a couple and they seem to work.

With your humidity up there I would be inclined to not take short cuts, otherwise you'llhave mushrooms in your elements. That being said, I'll be interested in what those in the know say.

[Big Red]

will it give off any fumes from other chemicals in it ??

[losfp]

It's not too expensive to just bulk buy some indicating silica gel (I like the indicating type so I know just how much moisture they've already soaked up!!!)... I bought 500g from this mob - http://www.proscitech.com.au/catalogue/c8.asp#C820

about 3/4 way down... $12 for 500g, not bad

[radar]

Des,

what do you put the silica gel in once you have it? I assume you put it in some kind of bag.

thanks,

André

[losfp]

Film canisters, with little tiny holes drilled in them

I've got a stack of them that live in my pelican case, and sometimes if I'm going away for the weekend or holidays or whatever... grab a couple and chuck them in the bag. They are not as effective that way obviously because it has to deal with the moisture in the air everytime you open and close it.. but can't hurt.

[dm_td5]

It's not too expensive to just bulk buy some indicating silica gel (I like the indicating type so I know just how much moisture they've already soaked up!!!)... I bought 500g from this mob - http://www.proscitech.com.au/catalogue/c8.asp#C820

about 3/4 way down... $12 for 500g, not bad

Thanks for the link but I just checked the order cost and they want $12 freight too
I don't like being overcharged on freight! I notice they seem to charge that for the 2kg as well, so probably their minimum charge.

I've notice the cat litter has a 1800 customer enquiry line. I think I'll be really painful and give them a call and ask if the product is simply Silica Gel, Ok to use with camera gear and if they have an MSDS. That should mess up their call centre stats for 2008

[colin_12]

The beuty of silica gel is that you can reuse it over and over again.
You just dry it out in the oven on a low heat.
Regards Colin

[BullcreekBob]

Here in Perth, we don't have much of an issue with humidity. What little we have is cheaply and easily dealt with by throwing in a few grains of rice. I find Arborrio works best.

[dm_td5]

Well my problems all resolved, thanks to a few enquiries with some of my work collegues. It's amazing how much of this stuff get's shipped around or used and discarded. So I now have some very pink stuff slowly turning blue in the oven.

Few things I found out. Best to use the pellets or granules and they come in different sizes, so to maximize surface area you want a smaller one (a smaller granual has a larger surface area exposed to a larger one relative to their respective volumes). They can hold about 40% of their volume in moisture. The blue/pink cobolt chloride dye is now being phased out and replaced with a less toxic dye that turns orange.

And I guess if there was no other option and you were really stuck, you could use the cat litter crystals, but it's not recommended... my wife also pointed out that I'd best keep the camera cases closed or that cat might

Thanks for the assistance

[Dargan]

So dm did you end up using the 'that "Crystal Silica" cat litter that they sell in Woolies' or source something else from your workmates. I'm not clear on what exactly you ended up. I'm on the badly named Sunshine Coast and it has been raining here for it seems like forever and I am starting to think I need some dessicating agents.

[dm_td5]

No I ended up sourcing some second hand silca gel pellets from work.

[gooseberry]

Not sure if you can get them in Oz, but if you're living in the tropics (Queensland, NT etc) I'd seriously consider getting an electronic dry cabinet (see here for an example - http://www.digihub.com.sg/SubCategoryLi ... egoryID=18) rather than using silica gel.

They're great for storing your camera gear, you can set the relative humidity and the cabinet will keep it constant and uses very little power (5W) (with silica gel, you have no real control over how dry the air gets and being too dry can also cause problems to your gear)

[Dargan]

European Camera Specialists have drying cabinets from $225@29 litres to $570 @105 litres. Pricy solution, but probably worth it if you have some of the expensive lenses one sees being used on the forum.

[gooseberry]

European Camera Specialists have drying cabinets from $225@29 litres to $570 @105 litres. Pricy solution, but probably worth it if you have some of the expensive lenses one sees being used on the forum.

Ouch... that is pricey. Just by way of comparison I bought an 80 litre cabinet for around S$130 - which is currently just over PP100. Guess the low demand and shipping costs ramp up the price in Oz.

[Dargan]

I started to think about making my own here is a site discussion http://photo.net/bboard/q-and-a-fetch-msg?msg_id=000MsG

[Andyt]

I have similar issues here in Port Hedland, at this time of year the humidity on the coast is quite high, at times when taking the camera outside for a quick pic I have gone to shoot and couldn't see a thing because of the instant "white out"

To date I have kept my gear in Pelican cases with the Pelican silica gel cartridges, every few months I replace them or cook them in the oven for an hour or so as recommended to dry them out. I went this way in preference to a drying cabinet as when travelling the case(s) come to and it was the best value. However I believe the SGel crystals are only suitable for short term protection and for travelling, the d/cabinet is the way to go for long term protection and peace of mind.

I would love a drying cabinet, and will probably end up getting one, but the cost + freight to here, starts you off in Lens Lust mode Still, as we insure our gear, don't put $20 filters on a $3K lens, and have suitable cases & bags etc, for some of us its just another expense to preserve our investment and make sure our gear remains reliable and fungus free

My 2c...........

[dm_td5]

Andy, you've got it in one there. I was going to ring ECS about there drying cabinets, but I expect the freight cost to be a killer. Could be as much as the cabinet! I'm going to see if I can source one out of Darwin as then it's only the barge freight to worry about.

I suppose there's always the wine cabinet, it keeps things at constant temp/humidity... just have to get rid of the wine

[Manta]

I suppose there's always the wine cabinet, it keeps things at constant temp/humidity... just have to get rid of the wine

There always seems to be room in mine.... the wine somehow doesn't stay there that long. Can't work out why.

[Viz]

...otherwise you'llhave mushrooms in your elements.

...by throwing in a few grains of rice. I find Arborrio works best.

Hahaha!
We are halfway to a decent risotto!!

[dm_td5]

I suppose there's always the wine cabinet, it keeps things at constant temp/humidity... just have to get rid of the wine

There always seems to be room in mine.... the wine somehow doesn't stay there that long. Can't work out why.

Two week holiday in the Margerat River filled mine back up.


Back on topic: Does anyone know a link to making you're own drying cabinet?

[Raskill]

Back on topic: Does anyone know a link to making you're own drying cabinet?

.

There was a thread about this recently, basically any wooden cabinet with a 25 watt lightbulb always burning in it. Produces a nice warmish enviroment to store your gear.

Shall try to find it.

[dm_td5]

Thanks found the thread: Dry cabinets - whats good and where to get em......

[Viz]

This has got me thinking about making one that incorporates the already warm/dry air from the computer that most of us have switched on quite often. Though you would want to filter it comprehensively for dust.

There are plenty of things that we have switched on as a matter of fact that also generate plenty of heat. I think I could even use my adsl router for this, as it is always warm, and always on.

The irony is that so much effor goes into dissipating this heat, but I have never seen it recycled.

[MarkW]

What makes you think that by sticking a bare bulb in a sealed area and elevating the temperature your going to reduce the humidity of that area. From even a rudimentry understanding of physics and gardening I'd suggest your only going to grow more mushrooms. High humidity and a warm environment is what mushrooms like.

The removal of moisture is not achieved by heating, it actually done by cooling the air and allowing the moisture within to condensate and fall out of solution.

[Benny2707]

I've got the It guy at work trained to keep the ones that he gets whenever he gets something shipped here.

Other than that did anyone end up finding somewhere is Sydney that you can buy the new and improved stuff?

[MarkW]

I stock a large supply of the stuff at A E Bakers at Blacktown for my company. Its used in high voltage zone power transformers and comes in a 12.5kg tin, Its a course grade blue sillica gel desicant, Bakers (Blackwoods) part number 00004216 and will set you back about $300 per tin. Maybe if you get a few of you together - dunno I just specify the stuff.

[Matt. K]

In an emergency a small quantity of uncooked rice will do the same job.

[AndyL]

A while back I helped build a dehumidifier. It consisted of a refrigeration plant scavenged from an old bar fridge that just needed regassing. Both the condenser and evaporator were mounted inside the bottom of a cabinet. The cabinet in this case was a nice looking glass case with seals, but a fridge shell is more than up to the task with minor modification. Air is blown over the evaporator (by a 3" fan scavenged from some electronic gear) where the moisture condenses and drains, then over the evaporator where it was reheated to a couple of degrees above ambient. There is excess heat from the condenser so it was necessary to externally ventilate part of the condenser plate using an adjustable divider and another 3" fan on a thermostat (which worked on a 2-4 degree difference with ambient).
A lot depends on how often the cabinet is opened and closed as to how much water it extracts, but it was generally between 4 and 8 litres per day with normal use at the time that it was built.

I am not to sure of the value of a light bulb in a box when used in the tropics. Seems like a recipe to increase fungus growth. Warmth + moisture + dark place = mushrooms. It might be useful for driving moisture from paper stock but that moisture is still in the air. This method could be useful for driving moisture from desiccant.

Andrew

[Benny2707]

I think I'm just going to buy one of the ready made units from ECS.

Less hassle me thinks.

Now I just need to find somewhere to hide it from the missus.

[cyanide]

I know this convo has morphed into one more about drying cabinets, but I wondered if anyone has any other recommendations on where to order silica gel from?

I've looked at the ProSciTech site, and if I absolutely have to I guess I'll order from there, but at $12.00 for 500g plus 12.00 postage plus GST, it gets expensive!! So I wondered if there were any other options people knew of?

Actually, I'll be down in Brissie in another week or two so I might check with PhotoContinental, since I assume they'd stock it too. But online source info would still be welcome. Alternatively, do any other Cairns members want to join a group buy...?

Cheers

[AndyL]

Cyanide, you could try eBay, but I think that the proscitech price is reasonable. I would go for the 2kg pack, cop the freight and be done with it for what $60 incl gst. Not like it is an everyday purchase and it is cheap insurance for a few years.

Cheers

[cyanide]

AndyL, I agree with it being worth it, and I will definitely gets some... just trying to minimise the pain a little, if possible.

I hadn't really thought about getting more than a 500g packet, though - fair point. How much do people use? I just figured 500g would be enough (especially seeing as it can be dried out), but hadn't really put much thought into it. I'd be using it in a Pelican 1600 case, with some also in the Slingshot, I guess.

[AndyL]

500g could be enough, but I think that you cannot have too much of a good thing especially in the top end. I would easily use 2kg in the plastic tub that I store my gear in.

You could spread the cost with another person if there are members close to you.

[Mr Darcy]

What makes you think that by sticking a bare bulb in a sealed area and elevating the temperature your going to reduce the humidity of that area. From even a rudimentry understanding of physics and gardening I'd suggest your only going to grow more mushrooms. High humidity and a warm environment is what mushrooms like.

The removal of moisture is not achieved by heating, it actually done by cooling the air and allowing the moisture within to condensate and fall out of solution.

Not quite true. It depends on whether we are talking about Relative Humidity (RH Expressed as %) or absolute humidity (expressed as gh20/gAir or similar, but very rarely seen). Raising the temperature per se will NOT change the AH as this is the total moisture in the air. It will, however, lower the RH as the hotter the air, the more moisture it can contain. This is why clouds form at altitude. As air rises, it gets cooler & can support less moisture. At some point, RH will = 100% and the excess moisture will be forced out of solution and will condense as a cloud. if RH = 100% at ground level, it will be foggy!)

To get back to the issue at hand. By raising the air temperature, we will LOWER the RH. This means that the air can hold more moisture in solution. It will then take up moisture from any surface moisture, thus drying out anything in contact with the air. This is how clothes driers work, and how they dry timber.

What I don't know is whether Fungi respond to AH or RH, but I would suspect that they would prefer a damp substrate to damp air. Therefore i would expect that raising the temperature would actually help prevent fungal growth provided that the only source of moisture is the camera gear.

The best solution would be to cool the air locally in a separate chamber, remove the moisture that condenses out, then reheat the air and blow the dry air over the camera gear. This would achieve the lowering of both the RH and AH.

Oh and Silica Gel works because it has a greater affinity for moisture at low (room!) temperatures, so it will absorb moisture from the air, effectively lowering both RH and AH.
At higher temperatures, it has less affinity for moisture, so the process is reversed. That's why you can dry the crystals out in an oven and reuse them.

[Benny2707]

I bought a pair of shoes on the weekend and got a few packets of the silica thrown in.

Score.

Need to buy more shoes.

[Viz]

OK, so I need 50 pairs of Lacostes to get adequate absorbtion...
I think I can sell this to my GF as a sound investment.

[Benny2707]

OK, so I need 50 pairs of Lacostes to get adequate absorbtion...
I think I can sell this to my GF as a sound investment.

Once you have the argument and the delivery down can you let me know how it goes and what you said?

[cyanide]

Well, I dropped in to PhotoContinental when I was down in Brissie last week and the only product they had was a small-ish (about 40-50g, I think) Pelican brand one, for $38. Ouch.

So I am going to order 2kg from http://www.proscitech.com.au/catalogue/c8.asp#, which it appears will cost me $36 for the silica gel and $12 postage - a much better deal. The postage feels a *little* steep, but overall it's still cheaper than I could find elsewhere. Sadly, their stock waiting time for that product is currently 4 weeks! Yikes.

[seeto.centric]

only problem with rice is that it goes mouldy once it's damp (i imagine roasting it would have similar effects to roasting silica gel?)

-j