Over the years the overwhelming approach to keeping valuables safe from humidity has been desiccants; Primarily due to the fact, of its wide spread availability in hardware and craft stores. Despite its availability, desiccants offer only a short term solution to humidity control, contrasted with the average sportsmanís lifelong need, of keeping sporting arms free of rust. For the average sportsman this translates into an expensive as well as ineffective solution.
How does desiccant work
For the most part, desiccants (Calcium Chloride and Silica Gel; leading desiccants on the market) capture and retain moisture via adsorption. Adsorption uses weak molecular bonds (surface tension), to trap wandering moisture molecules, on its porous surfaces. This type adsorption is called Passive Adsorption, due to the fact; the desiccant does not actually proactively remove moisture from the air, but rather waits around for moisture molecules to be attracted to its surface.
For desiccants, the overriding factor in its effectiveness is its limit of adsorption (the point at which moisture is no longer collected); once this limit is reached, an enclosure is no longer protected, leaving it vulnerable to corrosion from encroaching moisture-rich air. This limit can be reached in hours, days, weeks or even months, depending on the below factors.
- Type of desiccant
- Amount of humidity
- Amount of desiccant
- Adsorption limit for type
- Access of new, moisture rich air
As you can see knowing exactly when the desiccantís adsorption limit has been reached, is truly a guessing game, all the meanwhile your valuables are left unprotected.
Re-chargeable and Indicating Desiccant:
In the last 10 years, various products have been introduced, which try to improve upon desiccants; Mostly trying to address its two greatest shortcomings: Accumulated cost and knowing when the desiccant has reached its adsorption limit.
Re-chargeable desiccant products try to address the repurchasing of desiccant, by encasing it in a container which can be placed, either in an oven or plugged into a wall socket, in order to evaporate the accumulated moisture. While the addition Indicating Desiccant (mainly Silica Gel washed Cobalt Chloride) changes color to indicate when it has reached its adsorption limit.
While Re-chargeability and Indicating Desiccant offer convenience, it really does nothing to address effectiveness. The effectiveness of the desiccant is still dependent on the above 5 factors and regeneration of the desiccant involves leaving the enclosure unprotected for up to a day (leading brand) while the moisture is evaporated out. Regeneration of the unit would be to be repeated as needed, on the average twice a week, leaving valuables unprotected. As you can see using desiccant, requires a constant vigil over your valuables