Why don't they drip?
When making candles several types of wax are used. Each has its own characteristics. The wax used in most dripless candles contains Styrene acid. This acid produces a harder wax, which naturally has a higher melting point. The heat from the candle wick is not enough to melt the wax around the outer edge of the candle. So a solid wax rim holds in a pool of liquid wax. The thicker the candle, the less likely it is the heat from the wick will be able to melt the edges of the candle.
Why is my Dripless Candle Dripping?
Even dripless candles will drip if there is a draft or breeze. Heat normally rises but if a draft blows the hot air from the wick to one side, the hard edge of the dripless candle will begin to melt, allowing the liquid wax to drip.
It also possible the placing of the candle can affect its non-drip ability. If the candle is placed somewhere it could be unevenly heated up, it would be softer on one side and could drip. Prime examples of this are, near other heat sources, and in direct sunlight.
To help prevent these problems you can:
Featured Non Drip Candles