What you MUST have - Mold sealer

Metal molds sometimes come with their own sealing device, either a screw or a rubber plug. As far as I'm concerned, I don't like either option: the screw tends to damage the wick and with my molds, rubber plugs are a pain to insert and usually don't stay where they're supposed to, which has led to a few accidents...

A chunk of mold sealer the size of your fingertip and no wax will get through!

Mold sealer is a putty-like substance, usually white, slightly sticky and completely waterproof. You can find it in stores that specialize in candlemaking supplies but that is not the place I suggest you buy it from: it is generally overpriced considering the alternative.

Instead, go to your nearest do-it-yourself superstore and buy a small pot of plumbers putty. Plumbers putty does not harden and keeps its elasticity, which is exactly what we want. A 14 ounce pot will set you back about 8 dollars and will last you for years.

Do not hesitate to use it in abundance when needed, it will save you a good deal of grief.

Whenever you use two-pieces molds, like those designed to create a sphere candle, I highly recommend you cover the whole joint with a generous amount of mold sealer. Failure to do so may result in a half-sphere candle and a messed up countertop.

Another advantage of mold sealer: it will prevent water from entering the mold and mixing with the wax when you need to dip the mold and its contents in a water bath.