Simply Put

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

               3 Things Decals Don’t Like

 Heat - Eg., Storing next to a kiln or by a window in direct sunlight

Moisture - Alternating extremes of humidity and dryness (makes ‘em curl)

Pressure - Storing them flat in heavy  piles

                                                   More Expansively Put

 Re: Indefinite Shelf Life – Ceramic Decals are made from China Paints (aka. Overglaze Colors). China Paints are made from ground up rocks and minerals and metals and glass (aka. Inorganic Colors). [That’s why they don’t fire away in the kiln. They’re fire-proof.] Rocks don’t really go bad. Sometimes the mixing agent for the colors can become adulterated during the printing. Sometimes the covercoat can brittle with age. But the colors themselves are VERY stable. Typically, if a decal is bad, it was bad when it was printed.

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’).

 Basically, if you can get a decal to mount properly, let it dry 24 hours, use a slow firing cycle in a well ventilated kiln, you may never have a problem as long as you live.

 Re: Heat - Constant temperature is a good thing. Typically storing decals at room temperature is usually sufficient. Higher or lower temperatures are not a problem, however too many fluctuations of heat and cold will cause the covercoat to age prematurely. This is what has happened when you have a decal is brittle and wants to crack and break-up when mounting. Also, extremes of temperature are to be avoided - below freezing or above 90 F (the wax on the wax paper starts to soften).

 Re: Moisture - A constant humidity should also be maintained. High humidity tends to make the decals lay flat. Low humidity tends to make them curl. By alternating arid and humid room conditions, you eventually get nice, little tightly rolled tubes which are very inconvenient to work with and damage easily (once you crease a decal, it will blister along the crease lines when fired). And, of course, never get water on your decal unless you intend to mount it. [And don’t think that a little water spot won’t hurt. A wet place that has been allowed to dry equals a bad decal because when you go to use it, it won’t release from the paper were the wet spot was.]

 Re: Pressure - Storing decals flat in small piles (½” or less) is not a problem. Storing decals flat In thick piles (2 or 3’) will usually cause the decals to stick together and often become damaged when pulled apart. It also mashes the wax paper (that can come on top of the decals) into the decal and makes it hard to peel off before soaking the decal in water. (And you HAVE TO peel off any and all wax paper before soaking a decal in water. If any wax paper is left on the decal, it causes mounting and firing problems.)(Tip: If in peeling off some tight wax paper, you leave a bit of paper on the decal, just wet your fingertip, and scratch oft the remaining wax paper with your fingernail.)

 
                                               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 Tupperware containers
  These are shallow, air tight, and can be book-shelved on edge.
  Possibly use cardboard separators inside.

• Decal Display Box (good for un-cut sheets)
  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.