Gun Safe Buying Guide Part 9: Moisture, the Constant Battle

Editor’s Note: This is the ninth and final installment in our series about home gun safes. The series dives into detail about safe technology, mounting/hardening you safe, increased fire protection, specialty safes and higher-rated safes, and buying used safes. There is a lot of information to consider when buying a safe. Follow along with us as we take a deep dive into this subject.

SERIES:

• Part 1: Introduction to Gun Safes
• Part 2: Electronic/Biometric/Manual Locks
• Part 3: Anchoring Your Safe
• Part 4: Fireproofing Your Gun Safe
• Part 5: Understanding The Threats
• Part 6: Specialty Safes & Remodels
• Part 7: Quick-Access Safes
• Part 8: Buying & Selling Used Safes
• Part 9: Moisture, the Constant Battle

relative humidity  noun

1. The amount of water vapor in the air, expressed as a percentage of the maximum amount that the air could hold at the given temperature; the ratio of the actual water vapor pressure to the saturation vapor pressure.

If you ask most gun owners about humidity they will say it is bad for your guns. Yes, humidity can be bad for your guns. Too much and, oh yes, too little can be bad for your guns as well. So, to define the parameters of the battle, let’s consider the correct level of humidity.

Just Right

The NRA Firearms Museum recommendation is 65-70 degrees Fahrenheit, and 45% to 50% humidity. This should be a year-round constant, not an average. You could have an average of 50% humidity with 180 days of 0% humidity followed by 180 days of 100% humidity and still destroy your guns. Too much humidity, things will rust; too little humidity, and the wood stock on your rifle can actually dry out, crack and split.

Measure Twice, Cut Once

Just like the carpenter’s rule, the first thing here is to know the correct numbers. To get this I recommend buying two humidistats to monitor the humidity levels inside your safe. This will allow you to see if you need any humidity control. Now, why do I recommend two humidistats? This will allow you to check the reading against one another. Most of the retail models tend to be accurate at showing changes, but not an exact reading.

Once, you have your two humidistats you need to calibrate them (or get the error from a known measurement). This is not particularly difficult. To start the calibration process, you first need some iodized salt, distilled water, and a container. The container can be almost anything, so long as it has a flat bottom and can hold the salt and water mixture. Now, you need to measure a level teaspoon of salt and place it in a small container. Add enough water to the salt that it forms a paste. Do not add too much water, as this will skew your readings. Once you have made the paste, place both the humdistat (turned on, if digital) and the salt solution into the airtight container and seal it.

Leave this alone for at least seven hours and do not disturb the container. After seven hours, check the reading on the humidistat. If it does not read 75%, then the difference between the reading and 75% is how much your device is out of calibration. Generally, your device should read between 73% and 77% humidity (+/- 2%). I then either turn the adjustment screw if the humidistat has one, or I write the error amount on the meter.

One other great product I recommend is the Safelert from Liberty. This connected device allows me to check the status of the door, battery life, temperature, humidity and Internet connectivity via my smart phone, email or text alert. You can read about it here and all the functions if offers.

Do I Have a Problem?

If you keep your house heated and cooled and control the humidity with an HVAC system you may not need to spend your money on humidity control. However, depending on where you live and where your safe is kept you may have a small issue to a full-scale war on your hands. The solution should be defined by the problem. It could be as simple as adding a humidifier or dehumidifier to your home and your whole house will be more comfortable as an added benefit.

Tools for the Battle

Dry rod dehumidifiers heat to a surface temperature of around 100-120 degrees Fahrenheit. The heat creates a natural convection that slowly circulates warm, dry air throughout the safe on a 24-hour basis. This increases the temperature of the air inside to several degrees above the ambient outside temperature. Expansion of the heated air forces the moist air outside through the small cracks on safe doors leaving the dry air inside. It works best when mounted horizontally at the bottom of the safe. Lowering the humidity is a slow process. If you do not see the reduction of humidity after a couple of weeks then you may want to consider a longer unit.

An EVA-dry dehumidifier is filled with Water Glass Technology crystals that have a much higher absorption rate than traditional, desiccants. It is non-toxic and child and pet safe. You place the unit in your safe, and the silica gel crystals absorb the moisture in your safe. When the unit is full of moisture, the indicator window will turn green. Take the unit out and plug it in 8-10 hrs. The unit will renew itself and dry out the moisture. When the indicator window turns yellow put it back in your safe.

PEET Air-Circulating dehumidifier dries moisture inside the safe by raising the temperature inside the safe and circulating warm air. The warm air rises pushing the cold moist air down through the unit.

Desiccant moisture absorber automatically absorbs humidity inside the safe. It is filled with silica, a material that actively absorbs moisture. Silica packs are often found in bags of beef jerky to keep the meat dry and free of moisture. You should place at least three silica packs in your gun case, but you need to ensure they are not touching any of your guns directly. Silica packs can cause the metal on your gun to rust if they come into direct contact. Simply heat in the oven to reactivate.

Light bulbs will warm the air and may get you the results you want. However, I have one caution for you to consider. Overexposure to light can be just as bad for some guns. Overexposure to excessive UV can cause fading of some materials like mother-of-pearl grips and case colors on metal components. You should keep light exposure below 25 foot-candles for sensitive materials. If you decide to use light I recommend modern LED bulbs as they don’t emit UV radiation. The correct amount of heat to control humidity will be a trial and error affair, but it can work.

Conclusion

So there you have it, some really good options for combating moisture in your gun safes. When we think of risks to our gun collections, most of us likely think of theft or fire. But the danger of moisture is real and should be taken seriously. The good news is that there are some relatively easy and low-cost ways to win this war.