Question about humidity/coin holders
comma
Posts: 1,510 ✭✭✭
I keep all of my coins in a fireproof/waterproof safe. I have silica desiccants in there, but recently put in a hygrometer and realized the humidity was very high (70%+). I open the safe every 1-2 months at least.
This got to me to thinking. How much of a problem is humidity with coins, especially with those in cases or slabs?
And when a coin is slabbed, isn't that coin air tight, meaning it is trapping in moisture?
Just curious how paranoid I should be since my whole collection was stored in this safe and I was shocked to see how high the humidity was.
Thanks for any input.
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I can’t answer about humidity as it’s not an issue where I store my coins. However, I can say that none of the slabs are air tight. The seal is very good but it won’t keep liquids or gases from coming in.
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that seems to be high for an enclosed space, where do you live?? maybe it'd be a good idea to remove everything from the safe and place in zip-lock bags with silica packs. then make sure the inside surfaces of the safe are dry, followed by placing silica packs inside with periodic checks with that hydro-doohickey till it's a more manageable 40-50% or whatever you feel is safe. then place the coins, etc. back inside and keep them in zip-lock bags.
most importantly, figure out why the humidity in the safe is so high.
"The problem is, no coin holder yet devised is absolutely airtight. Even coins that have been encapsulated in sonically sealed, tamper-resistant holders by the major grading services are not 100 percent impervious. These holders are somewhat airtight, and the plastic of which they're made is chemically inert -- but they're not completely airtight, and air does come in contact with the coins inside, though admittedly at a greatly inhibited rate."
Source: https://www.pcgs.com/news/coin-preservation
Look up Intercept Shield and similar products.
Humidity doesn't mean much without knowing the temperature.
You could raise the temp 10 degrees and the relative humidity would go way down.
Same amount of moisture in the air though.
I live in Ga. We invented humidity.
I have some pretty humidity sensitive material and haven't noticed any problems.
As someone else stated 70% seems awfully high.
What does your local weather say the humidity is outside??
No way the humidity in your house should be higher. Unless you have an indoor pool or water
standing in the crawlspace.
Beware of cheap hygrometers from the drug store. They are much better than they used to be but...
To clarify, the humidity in my house is always kept below 50% (I live in the south).
The same gage was measuring 46% humidity when outside the safe.
I opened the safe, put the hygrometer in, left it in for a couple of hours, and when I opened the safe it was reading like 72%.
Any clues there? All that it is in the safe is coins, a few photographs and about 5 larger desiccant packets that were put in there a month or two ago.
I am paranoid about humidity and have a dehumidifier in the house. However, I just never even though about it being an issue in the safe with the silica packs in there.
Could it just be that it was evening out after being opened, and then closed? Should I have waited longer?
At this point, I took everything out of the safe until I figure out what's going on.
Yes, but it's the relative that matters because that dictates condensation
the archives here, if you dig enough, has many threads/posts on this subject being one it's of the most important and iirc have very good information.
You can put your coins in Tupperware containers or large zip-lock plastic bags and put a silica gel capsule in each container. Silica gel capsules will absorb moisture but need to be recharged by drying them out in an oven. They usually have an indicator showing when they are fully saturated and need to be dried out.
Worry is the interest you pay on a debt you may not owe.
Thanks for clearing that up.
I don't have an answer.
The humidity in the safe shouldn't
be higher than the rest of the house. Is it sitting on an outside wall?
It actually does usually sit near an outside wall, but when I did this test with the hygrometer it was sitting in the middle of the room.
That’s why I’m confused since the humidity in the house is never above 50%
Fluffy?
I guess the bottom line is should
I be concerned that I had coins in there for quite a while? I never saw mold or visible signs of water damage etc. it’s just the hygrometer that clued me in. The photos and paper that were in there aren’t warped or anything. I did have some photos in plastic sleeves where I could see my fingerprints though
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It is somewhat unknown and also somewhat dependent on what generation slabs/coins you have.
Local guy had a fantastic collection of RED Indian Head cents. He kept them in a safety deposit box for about 10 years. When he took them out around 2005, he had a decent collection of Red-Brown Indian Cents.
Now, those were older generations of slabs and we don't really know what the humidity was like in the SDB, BUT those early generation holders were definitely not airtight and not moisture impervious.
Also, all opinions you get on this forum are worth $0 at a MAXIMUM. We provide no insurance or guarantees with our advice. Soooo....even if it isn't necessary, it can't hurt to use a secondary containment system like an Intercept Shield box or a plastic tub like @PerryHall mentioned. It may not help, but it isn't likely to hurt.
...your silica packets are probably all soaked up with liquid like somebody already said here...dry them up weekly or get one that plugs into the wall...also, add some heat inside of the safe..they make little blowers that are silent...the key is having the temperature inside of the safe be slightly higher than the room it sits in
Fireproof safes have a concrete layer in them that contains moisture. This is part of why these safes work in a fire. You have to put in secondary airtight containers with desiccant before putting coins in this kind of safe. I had a friend that ruined many coins accidentally because he didn’t know this.
Mr_Spud
I’ve stored my coins in this kind of safe without secondary containers for most of my life with no issues until now. That’s why I’m so confused.
What is the sign of a “ruined” coin from being in a humid environment?
...the least you can do in the meantime until you figure it out is put a couple boxes of nice cigars in that baby
The moisture initially trapped in the safe concrete has evaporated. It's still a cold sink that can get funky. Peace Roy
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There is a lot of twists & turns with this. I suggest you speak with someone who is a professional in the safe business. With that said, I am not an expert by any means but some of the stuff that's out there is that many fire proof safes use a moisture impregnated material. Putting desiccants inside can draw that out of the material. Also, desiccants can draw moisture into an otherwise dry container if it's not air tight and deplete the usefulness of the desiccant rapidly.
If the humidity inside the safe is substantially higher than outside the safe then the source must be the safe or it's being drawn in by the desiccant.
Maybe you should give the hygrometer a try with no desiccant in there and see what happens.
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Short story: Lived 4 years on the beach in the Caribbean. Slabbed coins were store in the old notebook/eagle brand sleeves. Books were in my bedroom closet. NO ac in the condo. I use to have to Clorox the back of my dresser about ever 4-6 months due to mildew. Likewise, clothes in the closet needed rotating and washing to keep mold odor down. Long story - never had problem with moisture turn any copper. Stop worrying.
WS
I've bought collections of Lincolns stored in basements which all show evidence of verdigris.
My friends coins developed black corrosion spots all over from high humidity inside the safe. Not every safe does this, but many of the fireproof ones work for preventing fires by retaining water in a layer in the safe. It doesn’t matter if you dry it out, it absorbs more moisture. Like a desiccant pack, it’s designed to absorb moisture until it’s saturated. In a fire, it releases the moisture inside the safe and that’s what protects documents inside from getting burnt. If the humidity is as high as your hygrometer says it is, then it sounds like one of those safes that rely on the moisture to make them fireproof.
Mr_Spud
A couple thoughts: take them out of the safe, problem solved. If you want something safer then get a safe deposit box but test out the humidity there too. I also recommend intercept shields as jmlanzaf mentioned. Storing the coins in that system in a safe deposit box should solve your worries.
That is how my safe is constructed. I keep the slabbed coins and other small items within secondary containers, but have a bunch of other stuff that sits out 'raw'. I use one of those 'dehumidifiers' that are easily recharged by plugging into the wall - need to do this every 3-4 weeks, but I don't always watch it really closely. After 5 years or so, I have seen no change in anything stored in there.
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@comma.... As mentioned above, the humidity problem is due to the fire proofing material in the safe. This is a common problem encountered by people who store firearms in those type of safes. The firearms actually will rust if left long enough. The slabs are not air tight... though they do have good seals. Storing your coins/slabs in sealed vacuum bags will help... or get another safe without the fireproofing material. Then just keep desiccant bags with the coins. Cheers, RickO
Thanks for all the input guys. I get really anxious about this stuff and the irony is that I put all of my best stuff in that safe to keep it in the safest part of my home when realistically it was probably the worst place.
Quick followup question:
If slabs aren't air tight, why don't graded coins tone more? And if those aren't air tight, my cheap sentry safe probably isn't either so why does it contain moisture so well? (I understand the material has moisture but wouldn't that evaporate over the years?)
Move to an area with low humidity. The Mojave Desert would work. You'll sleep better and your coins will thank you.
Maybe you had sweaty hands when you put it in the safe!
The safe has a layer of material in it that retains water. Like if you had a desiccant pack that turns pink when it is saturated with moisture, it will retain that high moisture level unless you recharge it by heating in an oven at 350 degrees f for several hours. The silica in the desiccant pack, if saturated, won’t dry out an enclosed space, rather it would hold the humidity at a higher constant level.
It’s like a cigar humidor that holds the humidity at a certain rate so the cigars don’t get too dry or too wet. Lots of people understand that example. These work by having materials in them that just naturally equilibrate to a certain relative humidity.
Like sodium chloride, table salt, if saturated with moisture and stored in a closed container makes the air in the container equilibrate to 75.4%. It just does. Different things absorb and release moisture at different rates. So, the material in the walls of a fireproof safe absorb moisture until they are saturated to whatever level the material equilibrates to. Like a desiccant, but not to as low of a humidity as regular desiccants.
At my work I have large bell jars that have different saturated salt solutions that equilibrate the air in the jars to different humidities. I have one jar that equilibrates to 75.4%, one to 58.4%, one to 43.2%, one to 32.9%, one to 11.3%. The 75.4% one contains sodium chloride. The 11.3% one contains lithium chloride. The others contain different chemicals that equilibrate to their respective humidities.
They look like this
Mr_Spud
I think it was Morgan.
The fishbowl was sitting on Don Willis' desk in the video where he introduced the new holder back in July 2015.
The video is gone now but he was talking about how the holder was water tight.
Along with TrueViews, it was one of the reasons I gold shield re-holdered everything.
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Why is your clock melting? Or am I having a flashback.
It’s melting. The last time we had a lab cleanup people said that our gel color swatches looked sloppy. I couldn’t figure how to make them look neater so I put up a clock that matches their appearance. Now they look normal. Here’s a picture with the kind of gel color swatches I’m talking about
Mr_Spud
These coins have been stored in a Dansco since 1985, in a small inexpensive safe, with no dessicants, etc., the last 19 years near the coast in Florida.
To add, I’m not condoning carelessness, or disparaging prudence....just providing some data. If you have valuable coins that may be moisture sensitive, by all means take extra precautions.
Thanks for that info. Very interesting.
I'm a little confused though. If silica doesn't actually retain moisture and it holds/adds humidity, how does it ever work? Wouldn't it be holding/releasing any moisture it absorbs as soon as it absorbs it? Why would it only release that moisture once it is fully saturated?
I'm not great with science so maybe that's a stupid question.
I feel like I learned a hard lesson. All these years I thought I was helping by throwing silica packs into bins/boxes/safes etc. I knew you had to recharge them but never thought they could do harm if I forgot to.
You have to heat a saturated silica desiccant pack in order for the silica to let go of its water. Until it gets saturated it loves absorbing water from its surroundings. After it gets saturated it stops drying out its surroundings and can even give off a little bit of moisture, but if you heat it in an oven at $350 the water comes steaming out of it. Same concept for the fireproof safe, only with a material not as drying as silica desiccants but that holds moisture and reabsorbs and gives off some moisture to its surroundings, but if a fire happens it gives up its water and it steams out inside the safe protecting documents from burning because inside the safe gets real humid. It sorta works like that.
Mr_Spud
Thanks, that makes sense. How much should I worry about old silica packs giving off moisture? I have a lot of bins and boxes (not air tight, but enclosed with tight lids) with older stuff that I have silica packs in. Some are there for up to a year before I am able to change them. I always figured once they were used up it was fine to leave them there until I recharged or placed new ones.
I understand that the safe was doing this on an even larger scale.
I just looked up silica gel desiccants and from what I just read, they can start giving up moisture when saturated if the temp goes over 77 F, so some temperature fluctuations can cause them to make humidity go up in an enclosed area.
Mr_Spud
@Walkerguy21D Was your small inexpensive safe a fire safe?
Worry is the interest you pay on a debt you may not owe.
I use an Eva-Dry brand dehumidifier in the safe. There are probably similar products. Basically it is silica pellets encased in a plastic vented box that has a color gauge on it. When the gauge turns pink, the unit is saturated. You plug it in to ‘re-charge’ it (i.e., dry it out) until the gauge turns blue. I like these units versus guessing the saturation level of the packs and fooling with the oven. For me, generally it keeps the RH in the safe about 6 to 10 percentage points lower than the overall household humidity.
I'm guessing even if it wasn't the humidity on the coast is near 100% for a lot of the year, which would be higher than a firesafe would most likely get
It's a Sentry safe, that was already installed in the house when we bought it.
Actually as far as outdoors, the humidity level is generally around 75%, +/-, for 7 months
out of the year. This time of year more like 50-60%.
Indoors of course it's better, but in the dead of summer I set the thermostat at 78 deg during the
dau and 77 at night, and we use ceiling fans.