In the candle-making process, sinkholes are a common problem that almost every candle maker has encountered. The surface may look perfectly smooth, but after cooling, a depression forms in the center; some candles look fine right after demolding, but gradually sink after a couple of days. Ultimately, these problems are closely related to the shrinkage characteristics of the wax itself, the cooling method, and production details.

Why do sinkholes appear? Is white paraffin wax an advantage or a potential problem in this regard? And how can sinkholes be truly controlled?

Pouring temperature is crucial

Many candle factories understand pouring temperature only as "hot enough to pour," but for fully refined paraffin wax, this is far from sufficient.

If the pouring temperature is too low, the wax liquid lacks sufficient fluidity, easily trapping air inside, and the crystallization process will be uneven; however, if the temperature is too high, although it flows smoothly, it will lead to more significant volume shrinkage and is more prone to collapse later.

Empirically, fully refined paraffin wax is best poured at a temperature slightly above its melting point, but without excessive heating, allowing the wax liquid sufficient fluidity while avoiding unnecessary thermal shrinkage. This just right temperature control is a hidden key to reducing sinkholes.

Leaving a pouring hole for refilling

In actual production, leaving a pouring hole for refilling is almost standard practice. It's normal for the top of the candle to show slight sinking after the first cooling.  Refilling the wax at this point effectively fills the cavity formed by internal shrinkage.

When using white paraffin wax, the refilling effect is even better because of its high crystallization consistency. The refilling layer and the original wax body integrate better, preventing noticeable layering. This is why many high-end candle brands prefer white paraffin wax as their base wax material.

Appropriate wax blending is more stable than pure paraffin wax

Although fully refined white paraffin wax itself is very stable, in actual commercial production, many manufacturers will add microcrystalline wax, stearic acid, or special wax additives depending on the type of candle, to optimize shrinkage behavior and surface appearance.

The key here is not how much to add, but having a clear purpose. If your goal is to reduce sinkholes in your candles, your wax formulation strategy should focus on reducing shrinkage concentration and improving the continuity of the internal structure, rather than blindly pursuing hardness or gloss.

One-stop candle raw material supply has a greater impact on stability than you might think.

In the process of serving our customers, Junda Wax has discovered a very real problem:

Many sinkhole problems are not just due to the white paraffin wax itself, but rather to incompatibilities between different raw materials.

For example, the white paraffin wax comes from one supplier, the wicks from another, the dyes from a third, and the candle-making equipment is also different. Each component may seem fine individually, but when combined, various instability issues begin to appear.

This is why more and more export-oriented customers prefer to choose a one-stop supplier of candle production materials. From fully refined paraffin wax to wicks, dyes, and candle production equipment, the materials have been tested and used together for a long time, resulting in significantly improved stability. As a professional one-stop candle raw material supplier, Junda Wax can provide white paraffin wax, dyes, fragrances, wicks, and large-scale candle production equipment, maximizing the consistency of your candle production.

Junda Wax's practical experience

Our fully refined paraffin wax products have been exported to multiple countries and regions and are widely used in various applications such as pillar candles, container candles, and decorative candles. Many of our long-term customers were initially troubled by sinkhole problems, but by adjusting the cooling rate and pouring temperature, and combining this with the matching wicks and equipment solutions we provided, the problems were systematically solved.

This is why Junda Wax doesn't just provide white paraffin wax raw materials, but aims to help customers truly stabilize and mature their products from the perspective of the complete candle production chain.

If you are looking for a stable supply of fully refined paraffin wax, or want a one-stop solution for your candle production raw materials and equipment, please feel free to discuss production details with us. Many lessons are only learned after actually doing the work and encountering problems.