Why are candles molded upside down?

[StormySar]

I'm reading instructions for candles and they all mention that candles are molded upside down - so if I'm using a milk carton, the top of the candle will be at the bottom of the carton. Why?

I was going to try a new sort of candle, tie a wick to a metal washer, lay the washer at the bottom of the candle, pull the wick taunt (using the washer as a weight of sorts), then fill the mold and have the top of the mold be the top of the candle, and trim the wick to desired length on top of the candle.

Can I do this, or must it be molded upside down?

[notjustmamie]

I've never done molded candles, but the first thing that comes to mind is tapers--you couldn't mold them right side up!

Otherwise, no idea.

[Arduinna]

Well traditionally tapers were dipped not molded. When I've done those milk carton candles we never did them upside down.

[Think of Winter]

When you pour hot wax in a mold, it will shrink away from the top, making a funnel shape. I think the depression is less if the wax is not too hot when you pour.

You could make a candle in a milk carton, but if you want a really square top, it will be difficult to get. You'll probably have to top it up a few times as it cools to fill in the hole.