Adhesion describes how well wax holds on to a container surface. Containers range from glass and aluminum to ceramic or cement. Candle makers generally require the ability for wax to remain in contact with the container surface to fill as much of the container volume as possible. The candle industry sometimes calls adhesion problems “wet spots” because it appears moist anywhere the wax pulls away from the surface.

 Wet spots are cosmetic, but extreme cases can cause the candle to fall out of the container when tilted without a lid. Candles created for decoration or without a container naturally don’t require strong adhesive properties to function.

Wet spots occur when wax pulls away from the container edge. The science is relatively simple: wax expands when it heats up and contracts as it cools. Candle making involves melting wax into a liquid (expansion) then pouring it into a container where it cools down (contraction). The most dramatic volume change happens right after pouring the candle. 

Candles usually go through “micro” temperature changes throughout their life. Anytime the temperature changes, candle wax risks pulling away from the jar sides. This can happen during curing, shipping, and storing the candle, and preventing it is nearly impossible.

Adhesion problems are completely unavoidable since their cause is primarily due to changes in the environment. Unless you have some sort of magical control, your best option is to prepare candles with strategies and materials resistant to wet spots. 

Customers usually don’t care about or even notice them – this is a candle makers torment.  Pick up most any common candle at a store and you’ll see wet spots prevail!  Don’t lose any sleep over adhesion problems on your candles – they are merely distractions to the rest of your process.  Even if you could control the environment, they usually find a way to appear during transportation, shelf-life, or in the customer’s care.  Focus on creating safe, high performance candles instead.

We hope this was a brief informative clip of information to the spots on the side of most transparent candle vessels.

Have a blessed day,

Flower Fairy Candle Shop