Wax shrinking away from wicks

[Clarebear]

Hi everyone,

 

Can someone please help me with my wick issue. After pouring I've noticed the wax cracking around the wicks. 

 

Thanks in advance :)

[TallTayl]

Hi!

hot wax expands. The molecules swell and create pockets between the crystal grains to accept additives, like fragrance. As the liquified wax/additives cool the wax molecules shrink.
 

Some waxes (most soys) are rather brittle and will crack as the wax crystals reach their final size. Customers want good glass adhesion, so the soy wax additives stick strongly to the glass, causing internal stress as the wax shrinks to its final size. Often if poured too warm the cracks are a symptom of sink holes/cavities of air under the surface and internal cracks. The wax has no choice but to draw air down the wick as the wick is the path of least resistance.
 

Some wax blends, like IGI 4786, are rubbery and create deep wells on top that need a second pour. 
 

For all waxes, you need to find the balance between the pouring temp and your containers/room temp/humidity to prevent too much touch up to complete a safe candle.