Humidity expert needed!

Saam · January 3, 2007 12:45PM

Please help! I live in east Texas and my coins are kept in a fireproof safe. The humidity is always over 30% and I can't get it down although I have two dry rods going! I also tried silica, but it does not work either. Surely there is someone out there that has found a solution to this problem. The big coin companies have to have this figured out by now. What is the secret?

PrivateCoinCollector · January 3, 2007 12:50PM

Option A = Put a dehumidifier in the room the safe is in.
Option B = Move to California!

Bruceswar · January 3, 2007 12:51PM

You deal with alot of the same problems as many of us. Welcome to the forums. As a side where in East Texas? Now to your question you might try keeping your house at a different tempature. Humidity might be high in places, but if you keep your house at the right levels it will help inside.

fcloud · January 3, 2007 12:52PM

Welcome. Storing it in a room with AC may help.

Coxe · January 3, 2007 12:53PM

<< <i>Please help! I live in east Texas and my coins are kept in a fireproof safe. >>

Get them out of that safe. Fire safes are not for storing coins. They are destructive as they naturally, as you are learning, build up humidity inside them. They are also useless against burglars. Many can be simply taken away and any of them can be trivially penetrated with simple tools and things around your house.

I almost don't believe this post is serious. The fact that the safe was qualified as fireproof kind of hints at just a trolling of the forum. If not, just get them out of that box. Even East Texas isn't as bad as a fire safe. In more normal storage, an open cottage cheese cotainer (or similar cup) half full of Damp Rid (Home Depot and many stores sell that dessicant) and changed when it is saturated with water should help out a lot.

clackamas · January 3, 2007 12:54PM

Baby diapers absord quite a bit of water.

Saam · January 3, 2007 1:25PM

Thanks for your help. Since I can't move to California and I already have "AC" in my house, I will try putting a dehumidifier in the room for now. If I should not be using a fireproof safe for storage, what type of safe should I use?

PrivateCoinCollector · January 3, 2007 1:33PM

I don't agree about not using a Fireproof safe. That part about trapping in the moisture? The moisture is coming from the outside remember? Anyway, go to Fort Knox Safes they are the best.

cladking · January 3, 2007 1:35PM

Welcome aboard.

AUandAG · January 3, 2007 1:45PM

Heck of a problem...Are you keeping the coins for the long haul? If so then
I suggest you send them to me here in Las Vegas.....I'll keep them safe and
dry.....I promise.
bob

JapanJohn · January 3, 2007 1:59PM

I once worked in a Government Materials Science program for over 10 years. Much of my time was spent in the Navy Aircraft Corrosion Control Program and I, to this day, consider myself very much an expert in corrosion control.

IDEAL conditions for the storage of almost any item is between 25% and 40% relative humidity. Keeping metals in a vacuum would be ideal but not usually practical.

As long as you don't exceed 40% RH I wouldn't worry a lot however as a custodian of aircraft we did frequent inspections on them to check for corrosion. I'd recommend the same with your coins. Even putting coins under PERFECT storage conditions and not inspecting them frequently is pretty much just asking for trouble.
.
Some RH is good. A lot isn't necessarily bad. Much has to happen for corrosion to occur and the simple act of keeping coins in decent storage conditions should do it.

Buy some humidity indicators which cost about a buck apiece. They generally have 4 circles on them indicating 20.40,60 and 80% RH. They'll change colors when exposed to the amount of humidity present.

Next time you go to the museum look in the corner of the display box and many times you'll see a glass of water. What's the water for? To bring the humidity up.

Some humidity good.

John

Coxe · January 3, 2007 2:21PM

Yes, welcome too. AC is naturally dehumidifying. (I know that in the construction of my wine cellar as the cooling unit vendors harp on it.)

If you must have coins in your home and they are not low valued, you might consider a well hidden anti-burglary safe. Fire safes and gun safes are very limited in their protections against theft. It really depends on the value of the coins. A TL-rated vault is a high value one. I'd ask your lock and safe guy for recomendations as well as a good location for it. Kepe the fire safe around and fill it with rolls of pennies and nickels. The thieves can waste time with that.

edit>>
Didn't see the last reply. Next time you go to the museum look in the corner of the display box and many times you'll see a glass of water. What's the water for? To bring the humidity up. Humidity is essential for documents and things like that. An environment that promotes oxidation is not great for coins. Any impurities on the coin's surface, not necessaily salts but lots of things, when in the presence of water can corrode the metal.

MrSpud · January 3, 2007 8:42PM

I had a friend who stored some Dansco albums and proof sets in a fireproof safe. The Dansco albums grew muildew on them and the coins became a combination of toned/hazed and spotted. The proof sets became severely spotted with the clad coins developing deep pitted spots. I have read that some of the fireproof safes have something in their walls that promotes a temperature difference on the inner and outer surface of the metal walls of the safe which makes them prone to condensation. You can either stop using such a safe or put the coins into sealed containers with dessicant inside of them. Here is a cut and paste of some info I have posted before.

If any of the coins are really valuable you may want to consider the following information from the book Coin Preservation Handbook by Charles Frank.

And familiarity with the info from the paragraph titled other degratative materials from the same book might not hurt. If possible, avoid using those materials and avoid storing those materials in the same container you are storing the coins in. I've taken to storing my better coins in heatsealed Safety Flips or airtites in jars of metal cans with dessicant.

Tbar · January 3, 2007 9:03PM

I guess I will have to re-evaluate my plans for storing my coins. I too was planning on buying a fireproof safe for my house. Now I will explore other options. I do need a safe though. Good info here...thanks.

kranky · January 3, 2007 9:15PM

My understanding is that fireproof safes contain insulation which is intentionally loaded with moisture. The idea is that in a fire, the moisture in the insulation will help keep down the temp inside the safe by converting to steam. So your efforts may be lowering the effectiveness of the fireproof feature. I believe there is a type called a media safe which uses a different type of insulation but is more costly.

But anyway, 30% humidity doesn't sound like a problem.

morgansforever · January 3, 2007 10:25PM

All my silver coins are vaccum sealed. These Buff's have been sealed for years, no leaks, and no spots. A good idea for ASE's which are prone to milk spotting.

ttown · January 3, 2007 10:32PM

This is a function of your house not the gun safe. I don’t put my high value guns in a safe to rust. I’d suggest putting your coins in Tupperware to keep any moisture out that could be in your safe. Your guns should be rusting if you have that issue.

Saam · January 4, 2007 12:27PM

Thanks everyone for your suggestions! I have a couple of calls in to some safe companies, but no "for sure" answer yet. If I get this figured out I will let everyone know. I really thought some of the big companies would know the answer to this, but I guess they don't want to share! lol

RichieURich · January 9, 2007 4:28AM

to the Forums, Saam!

ttown · January 9, 2007 4:34AM

FWIW: I've kept coins both graded and raw in my safe for 20 years it should be no big deal.

MadMonk · January 9, 2007 4:39AM

As most have said, a fire"proof" safe requires a lot of special considerations. You can try to leave the door open as much as possible.
This will help keep the moisture absorbing elements from becoming too moist. You lose fire resistence though.

notwilight · January 9, 2007 4:58AM

I didn't respond to this at first because it asked for an expert and I'm not an expert. Now that I see that hasn't stopped the dissemination of misinformation I'll jump in and add my own two cents.

Relative humidity is the amount of water in the air divided by the amount of water that will be in the air at the dewpoint. The denominator of this fraction goes up with temperature. Thus, if the amount of water in the air is constant, heating the air lowers the humidity and cooling it raises the humidity. In the winter, outside air is low moisture so heating it will cause the inside heated air to be very low humidity.

Cooling air raises the humidity so how does an air conditioner lower humidity? As the air goes through the cooling coils if it goes below the dew point water is taken out of the air (thus you see water running out of air conditioning units) and so when it heats back up to room temperature, the humidity goes down. It may or may not go down below the outside air so air conditioning doesn't always lower the relative humidity.

Putting a dehumidifiier in the vicinity is a good suggestion but heating the inside of the safe is an option often used in gunsafes. If you can keep the temperature inside the safe higher than the temperature outside the safe you're almost guaranteed to lower the humidity. Unfortunately, I'm not sure you could get a wire through the door of a firesafe. These heaters are commeercially available. Some people have used lightbulbs successfully for years but there are many warning of the hazards of using a hot lightbulb and I don't feel qualified to recommend them against the warnings of others.

A depletable moisture absorber should be a great help too. They generally change color letting you know when they are full.

I don't understand the comment that firesafes have a worse humidity problem than other safes. They are generally better sealed so the humidity problem I could postulate would be to close a bunch of warm, humid air up in there and then cool it down. That would be a problem in any safe.

Lastly, some fire safes are also designed as security safes. I believe that fire protection is as important as theft protection so i recommend a combi safe that provides both. I don't recommend keeping extremely expensive coins in the house. If you do, then you become a target of professional theives and they can defeat almost anything. Keep the valuable stuff in a safe deposit box and use the home safe for cheap stuff.

--jerry

MrSpud · January 9, 2007 9:28AM

Since we aren't officially experts, here are a couple of copy and pastes from Conservation experts regarding the topic

Link
"According to Susan Maltby, vulnerable metal coins will
start to corrode when the relative humidity in the
surrounding air rises above 35 percent. Obviously, then, the
risk of corrosion is higher in a damp, humid place such as
Florida than it is in a drier climate -- the kind found in
Arizona, for example. "

From Link

"Fireproof safes and filing cabinets

Often valuable collections and records are stored in fireproof safes and filing cabinets. These thick-walled storage containers have insulation in their walls to prevent fire from damaging the items housed within.

Two types of insulation are used for these kinds of storage cabinets. One is a dry insulation which gives superior protection, but is higher in cost. The second type of insulation is termed a wet insulation and is generally found in lower priced, consumer safes and filing cabinets.

The most common type of wet insulation is a mixture of Portland cement, Vermiculite, diatomaceous earth, and glass fibers. During manufacture this mixture is poured between the walls of the cabinet and allowed to cure. In the curing process moisture is retained by the Vermiculite particles and the diatomaceous earth. During a fire the heat of the fire turns this moisture into steam, which is generated into the interior space of the filing cabinet or safe.

Unfortunately, often moisture is continually generated by the wet insulation and creates a very high humidity inside the safe or filing cabinet, even without a fire. These types of fireproof safes and filing cabinets continue to cure over long periods of time. In the meantime they may create severe mold problems on the goods stored within the cabinet.

Many people have found that they must leave the drawers open almost continually to prevent excessive moisture buildup inside the cabinet. This practice makes the cabinet useless as a fireproof cabinet and requires continual attention on the part of the staff. The solution to the problem is to purchase fireproof safes and cabinetry that have dry insulation and therefore do not have these problems with moisture release and high humidity."

--------------------------------------------------------------------------------

From Link
"In concordance with Jeanne Eichelberger's experience, a few years
ago I conducted a CAP survey for a museum which stored records and
film in fire-proof filing cabinets.

I put my data logger into one of the drawers and went to lunch. When
the data were downloaded it was clear that the %RH inside those
particular filing cabinets was approximately 15% higher than the
ambient conditions.

My recommendation to the museum were substantially the same as Ms.
Eichelberger's. Open the drawers weekly and leave them open all
day.

Thompson Conservation Lab.
7549 N. Fenwick
Portland, Oregon USA
503-735-3942 (phone/fax)"

">Does anyone have any experience with the use of fireproof safes for
>the storage of books? We are working with a collector who keeps
>most of the valuable items from his 18th century book collection in
>fireproof safes in his home. The size is about 3 1/2 feet. The
>concern is about the relative humidity in the safes. Instructions
>explain that there is water in the walls as part of the fire
>prevention design. This also causes vaporization. The manufacturer
>sends desiccant tablets that need to be regularly replaced and
>advises that books and other valuables be kept in Ziploc bags. We
>always advise that people not keep books in baggies because of the
>moisture. Does anyone have information, insights or references
>that might help us with this question?

My only encounter with this practice strongly indicates that it's
not a good idea. I once did an onsite preservation survey for a
historical society in our area, and they kept their most valuable
leather-bound books in a small fireproof safe. The interior smelled
distinctly musty when the safe was opened, and there were traces of
what I assume was mildew on the books. The historical society was
on the horns of a dilemma in that their collection was housed in a
lovely Victorian firetrap of a house, with very poor security
against break-ins and theft, so under the circumstances I could
understand their justification for using the safe.

I pointed out the environmental problems with the safe and
recommended that, in the absence of any likelihood that they could
move the collections to a safer building, they should open the safe
whenever staff was there to allow the air to circulate. I also
suggested that they might want to periodically take the books out
and open them to let them air out for a few hours.

That was the best answer I could come up with for that particular
situation. Under no circumstances would I suggest that books,
especially leather-bound books, be sealed in plastic storage bags.
Like the person who submitted this question, I'd be interested to
hear others' thoughts on the subject.

Jeanne Eichelberger
Head of Special Collections and Preservation
University Libraries
Binghamton University
Binghamton, NY 13902-6012
607-777-4309"

pontiacinf · January 9, 2007 9:30AM

ask laura, she's full of hot air.

and welcome

MrSpud · January 9, 2007 9:37AM

As for whether or not air conditioning lowers humidity, here is my experience. We monitor the RH where I work (I'm a Pharmaceutical Scientist). We have products that are moisture sensitive and are easier to manufacture when the humidity is lower so we try to pay attention. The RH tends to be low in the winter and high in the summer here in the Carolinas. The RH tends to be around 50% in the summer indoors with the air conditioner on and goes up to around 60% if it is raining outside (when the RH outside is 100%, the air conditioner acts somewhet as a dehumidifier and can remove some of the moisture and keep it under 65% quite easily but nowhere close to under 35% RH like Susan Maltby recommends). In the winter the RH outside tends to be lower and the RH tends to run at <40% as long as the heat is on. On really cold days the RH can even go down to around 20% RH indoors with the heat on.

puritan9 · January 9, 2007 10:30AM

Thank you for this post. I just ordered a $1000 safe that was the wrong one, just a fireproof one. Tomorrow morning I am going back to the dealer with lots of questions. Maybe I should keep them in my safety deposit box.

beantownboy · January 9, 2007 10:48AM

tmot99 · January 9, 2007 11:19AM

I have a couple of gas-tight boxes that I purge with nitrogen a couple times a month. Takes all of a couple minutes to complete the job. Keeps humidity low, oxygen out, and they are lockable.

librtyhead · January 9, 2007 11:36AM

How about ammo containers,pickling jars or maybe tupperware, as I have heard on this forum what if your kids were held hostage? I think your coins should be in a save deposit box $ or at least spread them around so they are not in one place................good luck!

Saam · January 13, 2007 3:09AM

Thanks again to all of you for your input but the problems still exists. Putting the coins in a bank safe deposit box would be no better than having them at my home. The bank has no special equipment to keep the humidity down but they do offer a better security system than most homes. I tried putting large silica containers in the safe but according to the manuafacturer of the dry rod type dehumidifiers I have inside the safe the dehumidifiers can't get rid of moisture that is being retained in the silica inside the safe. Doesn't anybody know of someone with this problem that has figured it out? Saam

410a · January 13, 2007 3:13AM

30%, 30%??? Thirty percent!!!!!!!!!!!!!!
What is your problem?

Now Elisabergs coins had a problem. In my expert opinion caused by humidity changes, but 30% isn't going to
harm your coins. If there is a fire or it gets hot where your safe is then you got a problem as a fire proof safe some who how puts out
more humidity in the warmth.

30%, http://www.trane-dealer.com/dis_50/2905/home.htm

410a · January 13, 2007 3:14AM

Tried to link you to my website.

Saam · January 13, 2007 3:27AM

The humidity in my safe will get no lower than 35% and that is only in the winter months. In the summer it will get to 60% and that is a problem!

410a · January 13, 2007 3:35AM

OK in that case. Open the safe or purchase a NON FireProof Safe.
How is the house humidity in the summer?
Believe me those fire proof safes are designed to add moisture
the warmer it gets.
The swing 60% to 30% is the problem.
Even at 60% Dehumidify the area the safe is in.

pharmer · January 13, 2007 3:57AM

<< <i> didn't respond to this at first because it asked for an expert and I'm not an expert. Now that I see that hasn't stopped the dissemination of misinformation I'll jump in and add my own two cents. >>

love it

Out of the safe, dude. Bottom line, if humidity is major concern. If security is, then safe deposit box. If you insist on a safe, gonna have to accept the rest of it.

410a · January 13, 2007 4:10AM

I am kind of busyand not putting this together too well for you, but I will say this I know little of metalurgy and quite a bit about RH%. Do you have a Sling Psychometer? or a store bought hygrometer? Are you experiencing swings in the RH% ? The swings is what will cause the problem you are trying to avoid. Even at 60% consistant summer RH% you don't have a problem. You will acquire a bigger one in a bank vault. I have seen the effects of wide swings. 35% is NOT a problem neither is 60% stable. Check out that safe I mean it, just do it. IF YOU ARE THAT CONCERNED THEN PLACE THE SAFE SOMEWHERE THAT YOU CAN PLACE A DEHUMIDIFER NEARBY PREFERABLY NOT THE BASEMENT.
Otherwise give me the city and state you live in and the glazing of your house and the window exposures along with the square footage, roof color etc and I will do a load calc for you and fax it to you and you can get the proper HVAC system for the house and use an old time metal safe without fireproofing. I really don't think you have a problem unless the RH% swings rapidly. Which has many causes. Regards, Michael

MrSpud · January 13, 2007 4:24AM

<< <i>Doesn't anybody know of someone with this problem that has figured it out? >>

If you really want to keep using the safe, and control the humidity of the air surrounding the coins at the same time, you can just use airtight containers with silica dessicant in them and put the containers into the safe. See page 1 of this post for details on how to use inexpensive containers to control the humidity of the air surrounding the coins

Humidity expert needed!

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