Tips from the Curator No. 1: Moisture and Temperature

Tips from the Curator No 1: How to get started conserving your artifacts: Moisture and Temperature

Conserving a firearms collection is more than just slapping some oil on guns and hoping for the best.

The goal of preserving is to retain all the best attributes of a collectible without damaging the piece and to protect the piece from the ravages of time. It also encompasses improving a piece in order to stop decay (commonly known as removing corrosion / rust).

Before starting with the guns, it is a must to analyze the environment of where the guns are being stored. Guns in display cases require a different approach than those stored in a gun safe.

Preservation is not expensive or intimidating and can be done by anyone: from a beginning collector to the most inexperienced museum curator.

Humidity and temperature are the two most critical aspects of preservation and yet few collectors pay attention to these factors. Anytime you enclose an artifact (safe or display case), you enclose the atmosphere around it, this becomes problematic when opening the enclosement and exposing the artifacts to sudden humidity changes. It can be compared to stepping out from a cool and comfortable air-conditioned house on a humid and muggy hot day…

It is difficult for us to feel subtle humidity changes. So here is what is required for you to monitor the environment.

Hygrometer and thermometer: This can be inexpensive and I recommend buying an older German made unit (Ebay). These range from $10 to $100, and it is important to buy a unit where the hygrometer gauge is rather large with well defined gradations. It is important to clearly see the difference in the readout, 1% humidity increments are best (these are often advertised as barometers, weather stations, etc.).

I do not recommend any of the modern digital thermometers / hygrometers. These Chinese made units have huge fluctuations and are not known for accuracy. A 5% humidity deviation in readout is common and not acceptable for this application.

The ideal humidity level is 50 to 55%. While many curators will tell you that less is better - they often overlook one critical aspect; guns are not just made from steel and they often have accessories. The 50% margin is an ideal compromise for steel, wood, leather, animal horn (grips and buttplates) and even paper (if you display or keep paper items like manuals or catalogs in your safe or display case). Humidity levels like 40% and below are detrimental to wood, horn, paper, and leather.

You may have bought a rifle in a desert state like Arizona, Nevada, or other and when receiving it, you may have felt that the rifle or stock was lighter… also the texture of the stock may have felt different. If you know how balsa wood feels like, you may understand what I am referring to. Those stocks have lost their moisture content and in low humidity states it is important to nurture the wood in order to keep an adequate moisture level.

An important tip: If you receive a rifle from a low moisture state and the stock/wood feels dry… allow at least two weeks of acclimation for the wood to absorb some moisture before firing it. Dried out stocks / wood have a tendency to break or split when exposed to recoil. These rifles are also much more prone to breakage in transit as the wood does not tolerate any drops, even if shipped in a well protected container.

Any humidity level above 54% requires corrective action, this will be discussed in Tips from the Curator No 5 on desiccants and moisture control.

Temperature is also a factor but more for leather and paper. Keeping your collection under 76 degrees is recommended. Winter temperatures should be at a minimum of 55 degrees. The less fluctuations – the better (see more about paper in our future numbered series).

Hygrometers and thermometers take time to adjust, so it is best to do a reading each time you open the case/safe. A second hygrometer and thermometer in the room where the case/safe is located is a must, keep in mind that these units are inexpensive, this helps you compare the humidity in the safe/display with the room. If the room has a better or identical humidity level, you can leave the case/safe door open for an extended period of time in order for it to acclimate to a lower humidity level. If the opposite is true, where the cabinet/safe has a lower/better humidity level. Open and close the case/safe swiftly.

Example: You open your safe and see that the humidity level is 52%, the humidity level in the room is 58%... in this case you should not leave the door open for any period of time.

You can correct the humidity level in the room with your home’s AC system. Running a conventional AC system (not a swamp cooler) will reduce humidity as part of lowering the temperature. Some modern AC units also have a separate dehumidifier feature which is great, especially in the spring and fall where temperatures can be pleasant but humidity levels can be high.

The use of a separate dehumidifier can be helpful but the unit should be far removed from the case/safe, ideally at the opposite side of the room. Venting and exhaust are a must as some of these units put out a lot of heat. You do not want this heat near the artifacts.

The goal is to come up with a very neutral environment with as little fluctuations in temperature and humidity as possible.

Tips from the Curator and their content are copyrighted by Anthony Vanderlinden (author) and may not be reproduced without the written authorization of the author.