Poor adhesion also looks like wet spots. You must note this is a very common problem with candles made in glassware. The research will show that even expensive soy wax candles of large manufacturers often have the same results. Container adhesion will not cause the candle to burn differently and is certainly not something you should be doing wrong.
It occurs because of the slight shrinkage that occurs as the wax cools and the small imperfections on any glassware interior. The wax can pull away from certain areas of the glass but remain stuck in others.
Solutions
Container adhesion should not be considered a product defect, as I have already stated. It is true that candles can look imperfect and that customers might prefer to not have them. So what are the alternatives? Clear glasses are more noticeable than clear ones. The best option is to use Frosted Glass. But, many people like transparent glasses. Clear glasses can add an element to a candle’s class and elegance. Clear glass sales exceed our frosted sales almost by 2 to 1. Let’s explore other methods to prevent adhesion problems in clear glasses used for candle making with soy wax.
This particular method of heating your glasses before pouring has proven to be very successful for many customers. Different requirements are depending on how much you manufacture. This can be done easily by using a heat gun or hairdryer to give the glass some heat. Your glasses could be preheated in the oven on a tray or plate before you start pouring. Glasses do not need to be heated, so there is no need to heat them. Some larger companies will put their glasses through a heating chamber on conveyor belts before pouring. It is said that this reduces container adhesion.
Container adhesion may be a hit-and-miss phenomenon. One batch yields great results and another produces inconsistent results. However, just like any testing, it’s important to document your pouring temperatures. It may help to slow down the cooling rate by placing your candles in a warmer area.
One other method customers use is to mix in some tart wax. This wax is meant to shrink. Customers may use a small amount to blend in the wax. This is possible for glasses where the glass shape of the candle goes out, and then comes back in at its top. Every shape of the glass is unique and will require different amounts. If you want to try this method, it will take some testing.
Other companies use an advanced technique that involves pouring the candles almost entirely Tart wax into a set of glasses, which then become the moulds. In this way, you can pour the candles first into these glass moulds. The candles will shrink when you take them off. A rod or pin would be used during pouring. Once the wax has been removed from the glass and the rod is pulled out, it’s possible to feed in the candlewick. Once the candle has been poured, you will not have any container adhesion. Glasses are often imperfect so the wax will not pop out easily because the glass will not have the same shape as the mould. To make your pin system work in glasses, you must allow for the wicks to be added to them later. This will only work in glasses with straight walls or glass that have a higher top than the bottom. This would apply to an experienced manufacturer who is looking for a long-term solution to ensure perfect candles concerning container adhesion.
We hope this helps you to see the common results of making candles with clear glasses. Also, it gives you an idea of the complexity of pursuing the goal of perfect candles.