Decals have an indefinite shelf life if kept properly.
In a perfect world, the ideal storage area has a controlled temperature of approximately 68° to 74°F and relative humidity of 50 to 65%. Warm climates usually necessitate air-conditioned storage as heat can soften the decal cover coat (and the wax paper that is often used to separate them) and causes the decals to stick together or the wax paper to stick to the decals. Paper curls can happen if the decals have been exposed to alternations of temperature and humidity. Keeping the decals stored “on edge” helps eliminate sticking together from pressure.
More Simply Put
Moisture - Alternating extremes of humidity and dryness (makes ‘em curl)
Pressure - Storing them flat in heavy piles
More Expansively Put
Most of that decals on the market are European (about 90%) and are of very high quality. ‘Bad’ decals are a rarity. In 33 years of decaling, I’ve only encountered a handful of ‘bad’ decals, and most of these were only incompatible with certain glazes (a phenomena known as ‘combatant colors’).
Good Storage Methods
• Packaging in plastic bags
and hanging on a pegboard
This Is especially good for resale (use a header card)
• Photo Albums
• A ‘Hanging File’ System
This Is better than a regular filing system because the folders don’t get bunched up at the back of the filing cabinet drawer.
•1” deep, rectangular
These are shallow, air tight, and can be book-shelved on edge.
Possibly use cardboard separators inside.
• Decal Display Box (good for
A box with free flipping cardboard folders AND a piece of carpet cut to fit the bottom of the box.
(This keeps the sheets from sliding underneath the cardboard.) The more cardboard, the better.
Don’t make the box too deep (12’ Maximum, front to back)
A good size for the cardboard Is 14’ x 17¾’
• The best display and storage system I’ve seen used 8½ x 11 clear plastic sheet protectors with a piece of 8½ x 11 card stock inserted. A sample decal and sizing information was on one side and cut up decals (pre-priced) were on the other side. These were then put into a 3 ring album for customer use. Decals were seldom misfiled, and when not in use, the albums were book-shelved (which means the decals were stored on edge). An affordable, effective, and efficient system.