Your product
What is being protected, and what does moisture actually do to it?
Moisture risk
The journey, the climate, the duration and the cargo's own water.
Desiccant selection
Four materials, not interchangeable. Capacity and temperature decide.
Customised packaging
Dose, pack size, pouch material and format matched to your line.
Moisture protection
A sealed enclosure held below 50% RH, verified rather than assumed.
Safe arrival
Storage and transport without corrosion, mould or claims.
Step 01
Start with the damage, not the product.
“Keep it dry” is not a specification. Different damage mechanisms start at different humidities, and the one you are fighting sets your target.
| Mechanism | Starts around | Typical victims |
|---|---|---|
| Steel corrosion | 60% RH | Machined parts, fasteners, tooling |
| Mould & fungus | 65% ERH | Leather, textiles, timber, food |
| Caking | Varies | Powders, salt, spices, food colours |
| Hydrolysis | No visible sign | Moisture-sensitive APIs |
| Popcorning | At reflow | Plastic-packaged semiconductors |
| Condensation | At dew point | Anything under a container roof |
Step 02
Work out how much water there actually is.
Three sources fill an enclosure: the air trapped when it was sealed, the packaging materials, and the goods themselves. The third is the one people forget.
Textiles, leather, timber, coir, paper and agricultural commodities are hygroscopic — they hold water and release it as conditions change. A container of cotton goods generates its own condensation even in temperate weather.
This step decides everything downstream. A carton is a silica gel problem. A container is a calcium chloride problem. Treating the second as the first is the most expensive mistake in the field, because the charge saturates in the first week and the cargo is unprotected for the rest of the voyage.
Rough water inventory
What fills a sealed enclosure
- Air sealed in at packing — worse in monsoon
- Moisture in corrugated, timber and dunnage
- Water held inside hygroscopic cargo
- Vapour permeating in over the storage period
Step 03
Four materials, four different jobs.
They are not substitutes for each other. Capacity, working humidity range and temperature decide which one is correct.
| Material | Capacity | Best between | Use it for |
|---|---|---|---|
| Silica gel | up to 40% | 30 – 90% RH | In-pack protection, cartons, barrier bags, general use |
| Clay (montmorillonite) | up to 50% | Lower temperatures | Cost-sensitive volume, cold storage, defence packaging |
| Calcium chloride | over 200% | High humidity | Shipping containers, high-moisture cargo, long voyages |
| Molecular sieve | around 21% | Below 30% RH | Dew-point specifications, refrigerants, gas drying, aerospace |
Steps 04 – 06
Seal it, dose it, then prove it worked.
The last three steps are where most specifications quietly fail — usually at the first one.
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Seal the enclosure first
Desiccant in an unsealed crate equilibrates with the whole atmosphere and saturates. A barrier liner is what makes the dose meaningful — it is not an optional refinement.
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Dose the net air volume
About 170 g of silica gel per cubic metre of space left after the product is in place. Dosing on external crate dimensions over-specifies, often several times over.
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Place it in the air, not under the load
A hung bag intercepts moving humid air. The same bag buried beneath the product does very little. Our bags are available with a hanging hook for exactly this reason.
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Handle the container separately
On an ocean route the box needs its own calcium chloride charge — four to eight Absorpoles for a 20 ft container. Without it the sachets inside are overwhelmed.
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Verify once, then dose on evidence
Indicator cards in a sample of packs on the first shipment. What comes back tells you whether you are comfortable, marginal or wasting money. Almost nobody does this.
Talk to our experts
Tell us what you are protecting — we will specify the rest.
Send us the product, the enclosure, the route and the storage period. You will get a desiccant type, a dose and a format back — not just a price list.