Dehumidifiers For Gun And Ammo Storage
BY Herschel Smith
11 months ago
This reddit/Firearms thread discusses dehumidifiers and the process of trying to keep your guns from rusting.
There is some confusion in that thread and I know this comes up sometimes so I thought I would clarify this issue for readers.
Customary dehumidifiers are nothing more than strip heaters. What happens is that when sensible heat is added to air, it moves horizontally across the psychrometric chart and (a) increases the dry bulb temperature while also (b) decreasing relative humidity.
Relative humidity is not absolute humidity. The number of grains of moisture per pound of dry air doesn’t change when sensible heat is added (or even removed, as long as we stipulate not condensing moisture out of the air). Changing the relative humidity changes the amount of moisture the air can contain. At a higher temperature, the air can contain more moisture, and lower temperature lower amount of moisture.
The air contains more energy at higher temperatures and thus it’s more difficult for the moisture to condense out of the air. Try moisture removal only occurs when the air is passed across a cooling coil down to the condensation line, passing that condensate to a drain pipe (usually with a running trap that needs to be inspected at least yearly to ensure no clogging and filled with Clorox). Then when the air must be sensibly heated again, with a true reduction in absolute humidity for use in the designated space. This is what happens when you air condition your home.
It isn’t usually practical to pass the air in your gun cabinet or gun safe through a cooling coil to remove moisture. The only other option for conditioning the air is to pass it over a strip heater thus changing the relative humidity, not absolute humidity.
As long as the space where your guns are located is already conditioned, i.e., your home, that’s usually not necessary. However, I do a little extra by putting desiccant in my gun safe to ensure the driest possible environment.
I don’t like the idea of a strip heat causing an increase in dry bulb temperature in my gun safe, mainly because of possible malfunctions.
If your gun safe is located in an unconditioned space like a basement, you may have to consider strip heating. The better option would be to remove your safe and put it in your home. I don’t have a safe in my garage for that very reason (and also because of possible theft).
On December 18, 2023 at 6:31 am, Bill Buppert said:
I haven’t used strip heaters for the reasons you posited, Herschel; I use wicking bags now.
I still have a safe in the garage because of space constraints and a fair number of tools in the house.
I store rechargeable “wicking” bags in the safe and run an active dehumidifier in the garage and the house in my library (I live in FL now) and monitor via hygrometers. I recommend that you use a 10x formula if you get a dehumidifier (if the ad copy reads 4500sqft = 450sqft) to maximize efficacy.
On December 18, 2023 at 8:57 am, Herschel Smith said:
Bill for the benefit of me and the readers can you drop a link for your devices?
On December 18, 2023 at 2:34 pm, Bill Buppert said:
Herschel,
Amazon:
Dehumidifier:
4500 Sq. Ft 70 Pint Dehumidifier for Basement, COLAZE Dehumidifiers with Drain Hose for Home Bedroom Bathroom Large Room, Auto Defrost & Full Water Alarm & 24H Timer with 1.59 Gallon Water Tank
Wicking Bags:
Wisedry 2 x 500 Gram [2.2 lbs] Rechargeable Silica Gel Car Dehumidifier, Microwave Fast Reactivated Desiccant Packets Large for Gun Safe Closet Basement Garage Storage Moisture Absorber Bag Reusable
Hygrometer:
ThermoPro TP53 Digital Hygrometer Indoor Thermometer for Home, Temperature Humidity Sensor with Comfort Indicator & Max Min Records, Backlight Display Room Thermometer Humidity Meter, LCD
On December 18, 2023 at 5:59 pm, ZERO[F2G] said:
36 year HVAC contractor chiming in. If your basement is not condition then I recommend resolving that issue. assuming your forced air system and duct system is in the basement its an easy do it yourself fix. Go to your local hardware of farm and house store; purchase 2 or 3 4×10 wall/ceiling registers and 1 6×12 or 6×14 return air grille 2 is usually enough but on larger homes we often use 3.
Cut the return central if possible, and cut in the supply registers more perimeter. Avoid cutting them in next to a long branch run, of if you have several branch runs clustered. Most of the time if you have a well designed duct system that won’t matter, but if your duct system is sub par it could.
Next if your perimeter basement walls are not insulated, I would highly recommend doing so. It cuts down greatly on the heat loss in winter especially, but also has a reduction on heat gain in winter.
Unless you know what you are doing, I would recommend hiring an insulation of general purpose contractor for that.
Next whether next year 5 years 10 or 20 years from now, I cannot stress the importance of hiring an HVAC contractor that has the tools and training to evaluate your duct systems performance and that contractor should be performing a Manual J load/loss calculation to determine equipment size.
If the contractor asks what your square footage is, and based on that number tells you equipment size, send him packing. There simply is no reliable BTU to square footage model. Proper calculations are the only way to get it right.
Your duct work is the most important aspect, it is the veins and arteries for the heart (furnace/Air handler).
No matter how fancy and how efficient a salesman tells you their brand is, if the duct system has issues their equipment will have issues.
De-humidification, and ventilation are also a major factor, again half of us in the HVAC industry know what we are doing, and half of us just sell wonder machines, choose wisely on whom you select.
And those of us that do it right are not always the most expensive, it varies hugely from job to job.
Last year I went to a large 3 system home, after evaluating that the duct system was not ideal, but it was adequate. I gave a bid of 25,000 to replace all 3 systems. The current systems were single stage propane furnaces with single stage A/c only condensers. My bid war for Bosch IDS duel fuel systems. That means inverter driven compressor heat pumps, with back up propane furnaces.
The homeowners then asked why my price was lower than the first bid they got of 30k, which was for single stage propane furnaces, and strait cool condensers of a bit lower rated efficiency. I stated that our business model was to meet a profit margin, insure the customer is happy with the system, to build a long term relationship, and in doing so hopefully gain referrals, in other words not looking to make the highest profit per install.
Sorry I know this was long, just wanted to get it out there.
On December 19, 2023 at 7:52 am, xtphreak said:
1) Desiccant, with indicators to show when it needs “recharging” (actually a long slow bake in an oven to drive out the collected water).
More is better.
2) Silicon impregnated gun sox (synthetic material to avoid absorbing water).
3) SUPER SECRET WEAPON AGAINST RUST!!!
Regular cleaning and for weapons not often pulled for active duty….
RIG Grease by Birchwood Casey.
I have and use a RIG RAG, A sheepskin impregnated with RIG GREASE.
For detail wiping, I use cotton flannel with the RIG GREASE thinned slightly with gun oil.
It doesn’t need to be gobbed on, a very thin layer works quite well.
Provides a very protective coating, easily cleaned off for use, simple.
Cleaning, wiping down, whatever you call it, endures you are aware of changing conditions.
Monitor those dessicants!
I have extras (stored in airtight containers) so I can rotate out any needing to be dried out without delays
In the nuclear industry we call it Preventative Maintenance & Inspection.
On December 19, 2023 at 7:55 am, xtphreak said:
Oh.
I have no affiliation with Birchwood Casey or any vendor of their products other than being a satisfied user for literally decades.
On December 19, 2023 at 8:39 am, Bill Buppert said:
What xtphreak says, I service desiccant bags quarterly or more often if needed. If you live in a humid climate, good for your vehicles too.
Noted on RIG, thank you.
On December 19, 2023 at 2:13 pm, Adino said:
I like these:
https://www.amazon.com/Improved-Eva-dry-333-Renewable-Dehumidifier/dp/B000H0XFCS/ref=cm_cr_arp_d_product_top?ie=UTF8
I find the ‘indicator’ on the front to be useless, which if you read the reviews people get mad that it doesn’t ‘work’ because the ‘indicator’ doesn’t show it to be dry. It’s dry, the pellets chameleon routine just depletes – and/or gets ruined if you leave them plugged in too long.
I bought mine a long time ago when they were cheaper (they do sell 6 packs). I rotate them, I put 4 or 5 in the big safe and change them out 2 to 4 weeks depending on time of year and humidity levels. Recharge for 48 hours. Repeat.