What causes a candle to be hollow?

[BrySC]

I melted down a candle today, and was surprised to see that it had a hollow chamber inside. I always poke relief holes. Any ideas?

[Janette]

Perhaps your relief hole was narrow and your re-pour temp a little on the low side. The relief hole could have become plugged before the bottom was filled.

Janette

[topofmurrayhill]

I melted down a candle today, and was surprised to see that it had a hollow chamber inside. I always poke relief holes. Any ideas?

There are relief holes and there are relief holes. They work better I think if you use something like a chopstick that isn't too skinny. Actually I use the blunt end of the chopstick to make the hole even wider.

As you know, the wax shrinks a lot as it cools. If you did nothing, you'd either have a very deep sink hole in the center, or air would get sucked in around the wick and cause cavities in the center of the candle, or the outside wall of the candle would get dented in, or some combination of the above. Air is just taking up the space where the shrinking wax was.

The purpose of relief holes is to make sure that air gets sucked in as the wax shrinks, but the cavities are right up there where we can see them and fill them in with wax. You just have to make sure the sucking happens properly by making good holes and ensuring they're open at the time the wax is really shrinking a lot.

HTH.

[BrySC]

Well, from what y'all said, I think I know what my problem is. I was using a skewer, which is very thin. I guess the hole was becoming clogged because it was so small. I knew I could count on this board to figure it out. Thanks!

[mizbizzyb]

I use a toothpick and drag it a little to make sure there is enough room to have wax go down in the tunnel - if needed.