So, I'm in the Philippines and I see this container of Tamarind candy. The container looked waterproof, so I bought it and I think I'm gonna throw a micro-box here in the Manila City Limits. Anyway, while eating the candy, I come across a packet of silica gel and annoyed, I throw it in the garbage.

Then, I dive for it thinking: "Hey, aren't these supposed to absorb moisture?"

So I read up about them on Wikipedia and heres what it has to say:

In many items from leather to pepperoni, moisture encourages the growth of mold and spoilage. Condensation may also damage other items like electronics and may speed the decomposition of chemicals, such as those in vitamin pills. By adding sachets of silica gel, these items can be preserved longer.

Silica gel may also be used to keep the relative humidity inside a waveguide as low as possible. Excessive moisture buildup within a waveguide can cause decreased TX/RX gain by increasing Voltage Standing Wave Ratio (VSWR). The beads of water that form and condense inside the waveguide change the characteristic impedance and frequency.

So my question is this: Could silica gel help preserve a letterbox in the event of a little moisture or condensation?

any thoughts?

Others before you must've had this thought, also. I have seen letterboxes with silica gel in them. I will be glad to see some responses to this.

't'
dtandfambly

I save the little packets as I get them (shoe boxes, etc.) I have put a few in with my logbooks when i know the plant location is pretty damp (This is Washington, after all!). Though none have been out long enough for me to have a definitive answer... but I'll let you know this spring :-)

HP

If I remember correctly, the general consensus is that they will work in humid conditions, but not an outright soaking.

HOWEVER, there was some real concern about their danger to animals who might get into the box--and accidentally consume the silica gel.

dewberry

Quote

Anyway, while eating the candy, I come across a packet of silica gel and annoyed, I throw it in the garbage. ... So my question is this: Could silica gel help preserve a letterbox in the event of a little moisture or condensation?

I would think so, but have no definitive evidence. (Texas is not so moist!)

My concern is, did you find the silica packet IN your candy container!??!? ;-)

(My daughter broke a mercury thermometer today. I guess I just have safety on the brain! ha ha!)
S of "the PEAS"

Unfortunately, I have experience with children who consumed silica gel. I won't say any names, BUT I did call Poison Control. Their response was that it is not poisonous (to children, anyways) just a choking hazard. It can swell up in the espohagus, if consumed in high amounts. Mine were just "tasting" it, so they were OK.

't'
dtandfambly

Wiki also has some info about the safety of it:

Alone, silica gel is non-toxic, non-flammable and chemically unreactive. However, some of the beads may be doped with a moisture indicator, such as cobalt (II) chloride, which is toxic and may be carcinogenic. Cobalt (II) chloride is deep blue when dry (anhydrous) and pink when moist (hydrated). This is the reason most silica gel packets are labeled as dangerous or poisonous when eaten.

So apparently, if you have none of the dyed beads, they are not harmful.

so it is a bit of a pain to determine if you
have toxic silica gel one has to open to
see if the beads are colored or not.
groan.
I had never thougth before of possible toxicity to animals.

The gel packet I have is clear. I don't think a small amount of carcinogens will really affect anything anyway, seeing as we've polluted almost all available natural water sources.

Did any of you catch the story of the bay in CA whose cinnamon and vanilla content skyrocketed around christmas because of the "Treated" runoff from waste treatment plants?

Scary stuff.

usually they have di not eat stamped all over them. I have seen them in abunch of geocaches around here.

Red Soup

Quote

Could silica gel help preserve a letterbox in the event of a little moisture or condensation?

I don't believe the effect is significant. If the container is leaking, the amount of moisture involved will quickly overwhelm the silica gel. If the container isn't leaking, it'll help for a while, but the humidity introduced by each finder opening the container will eventually overwhelm the silica gel.

I think the only way to make silica gel accomplish anything long term is to dry it out every now and then, like toss it in the oven or something. It simply cannot absorb moisture indefinitely.

It might be interesting to know if packets of silica gel might be used for box service. Like, you could carry a couple with you while checking on your boxes. If a box seems a bit damp inside, maybe you could just toss a packet or two in there and let it help dry things out over the next few days. Next time you visit, take that packet out and maybe throw in another. Take the used ones home and dry them out.

-- Kirbert

I've tested these silica packs in the field over a year ago....and they only work to absorb general moisture within a box. If they become totally soaked, they actually HELP keep the box moist...NOT a good thing. After trying them out in 10 different boxes with virtually the same results....I tossed them all.

LW PhD
"Nice Counts"

It's so nice to benefit from your experience.
You don't write about what you imagine will work or not work.
You share what you have seen work or not work.
"That" counts, too.

We'll not try to re-invent the wheel with these little packets.

Thanks,
Mama Cache

And yet, my experience is only for my area of the country. I'm telling you what works HERE. Other parts of the country may have different experiences....but I still think it's helpful hearing what works in as many places as possible.

LW PhD
"Nice Counts"

I don't use them down her in the *high humidity* south. What I had in mind was doing an underwater box and putting a couple in that just for the condensation from being in the cool water not to soak up any leaks. I know it doesn't work THAT good. :)

Shiloh

I think they work great! I use them in all my boxes. I put them in the baggie with the logbook. If you box gets really wet from rain or flood of course they won't work. Let's use common sense folks! If this is the case, it is the box you need to change. ;)

Common sense would dictate NOT puttting the gel pac in a baggie with the logbook. If it ever got soaked up a lot of moisturew it would be like packing a sponge with the logbook. Then again, if the gel pac were wet, chances are the logbook is already ruined.

LW PhD
"Nice Counts"

We recently found a letterbox down in Florida with a silica pack in it. Everything in the box was in good shape, but we still had to wipe down the inside of the box and the baggies to remove the moisture from condensation. We haven't found any here in NY so I have nothing to compare, but I am not convinced they really help much ... maybe the box just needed more than one pack, or maybe they just don't work well in areas of high humidity.

Happy boxing,
Padfoot Treehuggers :)