Service desiccant when its indicator calls for attention or the storage enclosure no longer maintains its humidity target. The interval depends on how much moisture reaches the material. A closed, dry safe puts a different demand on it from one opened frequently in a damp room.
We recommend a monthly reminder to review the humidity history and check the indicator. Service the desiccant sooner if readings stay above target.
Watch the storage conditions
For a stable mixed collection at ordinary indoor temperatures, 40–50% relative humidity is a useful working target, unless a firearm requires different conditions. [1]
Use a temperature-and-humidity monitor with saved readings near the firearms, away from direct heat from a heating rod. Our gun-safe humidity guide explains choosing a monitor and reading its history.
A brief rise after opening the safe may settle once it closes. Humidity that remains above target while the door is closed calls for a closer look. Check the desiccant’s indicator and inspect for moisture introduced with the contents.
After drying or replacing the material, compare the following days’ readings with the earlier record. A sustained return to target shows that servicing helped.
Read the indicator for the product you have
Some accessories use indicating beads, while others rely on a separate humidity card. Follow the colors shown on that specific indicator; color systems differ between products.
The separate Desco 13853 card supplied with XeroMag reports relative humidity around the card. Its spots move from brown toward yellow as conditions become more humid; read them against the printed reference. Desco allows up to eight hours for a response to a humidity change. [3]
The colors are reversible. A card that looks dry during an inspection may have changed back after an overnight rise, so use a logger when you need the history. Replace a Desco card exposed to 60% RH or higher, when its instructions no longer consider it accurate. [3]
The card reports local humidity rather than remaining desiccant capacity. Check for incoming moisture as well as servicing the material when humidity rises.
Drying and replacement are different service options
Reusable desiccant can be dried to remove accumulated water, then returned to service. The required process depends on the particular material and its container. Silica-gel conservation guidance and activated-alumina supplier instructions specify different drying arrangements; use the procedure for the material being serviced. [4, 5]
For a removable fill, fresh dry replacement material is another option. Refill the accessory and return it to the storage enclosure without leaving the material exposed to room air unnecessarily.
Don’t heat an assembled XeroMag. Remove its consumables for servicing. The housing has a lower temperature limit than the temperatures used to dry loose activated alumina, so putting the complete insert through a bead-drying procedure can damage it.
After servicing, keep the unused material sealed until needed. Desiccant left open on a shelf can take up moisture from the room before it reaches the safe.
If servicing becomes more frequent
A shorter interval can indicate more incoming moisture. Check whether the safe is being opened more often or the room has become more humid. Dry case padding separately and check that the safe’s door closes fully. A sound enclosure seal reduces the moisture entering between uses. [2]
If the room stays damp, compare inside and outside readings. Our garage and basement storage guide explains keeping a drier safe within wetter surroundings, including when room drying can help.
Keep the VCI element on a separate replacement record if the accessory includes one. Humidity readings show moisture conditions, while inhibitor replacement follows its own instructions. Cortec calls for replacing VpCI-170 more often than every two years in leaky enclosures or where doors open frequently. [6]
XeroMag makes the consumables accessible
XeroMag is designed to take the place of a compatible firearm’s magazine during unloaded storage. Its removable baseplate gives access to the activated alumina desiccant and separate Cortec VpCI-170 inhibitor element. You can replace either consumable while keeping the insert.
The separate Desco card makes a visual humidity check part of the same inspection. Record desiccant servicing dates alongside your humidity history to see how its service interval changes. Keep the inhibitor replacement date separately. XeroMag works without electricity or batteries; choose the listed configuration for your pistol or AR-15-pattern firearm.
Sources
1. Canadian Conservation Institute: Storage of Metals, CCI Notes 9/2, stable mixed collections.
2. Canadian Conservation Institute: Silica Gel—Passive Control of Relative Humidity, enclosure leakage and moisture demand.
3. Desco: Humidity Indicator Cards, TB-3087, indication and response instructions.
4. Canadian Conservation Institute: Preparing silica gel for contained storage of metal objects, drying and servicing.
5. Wisesorb: Activated alumina desiccant beads, supplier drying instructions for loose material.
6. Cortec: VpCI-150 and VpCI-170 Foam Tape, inhibitor replacement instructions.