Candle Wick Size Chart

In short THIS IS A STARTING POINT FOR A BURN TEST AND IT IS NOT AN ANSWER, which is worth saying at the top rather than in a footnote. Wick sizing is the one part of candle making that arithmetic genuinely does not reach. The right wick depends on the wax, the fragrance load, the dye, the container glass and the wick series itself, and every supplier's numbering runs a little differently. What a chart can do is narrow the first test from a dozen candidates to two or three. It cannot replace the test. With that said, the standard starting points by melt-pool diameter are: up to 5 cm, CD 3 or ECO 1; to 6.5 cm, CD 6 or ECO 4; to 7.5 cm, CD 8 or ECO 6; to 8.5 cm, CD 10 or ECO 8; to 9.5 cm, CD 12 or ECO 10; and to 11 cm, CD 14 or ECO 12. Above about 10 cm a single wick has to drag a melt pool right across the jar and generally cannot without running far too hot, so two wicks each serving roughly half the diameter is the usual arrangement, and three above about 15 cm. BOTH WAYS OF BEING WRONG COST YOU, AND ONE OF THEM MATTERS MORE THAN THE OTHER. Too small and the melt pool never reaches the edge: the candle tunnels, most of the wax never burns, and the scent stays in the jar. Too large and the flame runs high, the candle soots, the wax burns off quickly, and the container gets hotter than it should — which in glass is the failure that actually matters rather than merely disappointing. When you are between two sizes, test the smaller one first. HOW TO RUN THE TEST. Pour identical candles with two or three candidate sizes, cure them for the same length of time, and burn each for four hours in a draught-free room. You are looking for a melt pool that reaches the edge at around two hours and is no more than about twelve millimetres deep, a flame that is steady rather than tall or flickering, and no soot on the glass. Weigh each candle before and after and you have its burn rate as well, which is worth more than any published figure. Nothing on this page computes flame height, glass temperature or a flash point, and no chart anywhere can certify that a combination is safe.