With
candle molds it is best if the mold is warm when wax is poured into
it. Metal
molds are rarely a problem in this manner, the wax heats
up the
metal very well and quickly as it is poured in.
Milk cartons
work very well too, but paper never really gets
warm or
cold - it just
doesn't hold heat well. Sand is another classic candle mold. The real problem occurs with
glass.
When pouring wax into glass, the glass is the final container - it
is rare to ever take the wax out of the glass after it has been
poured. Wine glasses can make excellent candles, a nice rose colored
wax with a hint of strawberry, or a deep burgundy. These candles
become the wine.
If the glass is cold as the wax is poured in, the wax will harden
right where it is poured in and leave a thin layer on the glass.
To avoid this, the easiest thing to do is to take the glass and
place it in warm water for awhile. Glass takes awhile to heat up
and to cool down. Make sure to dry out the inside of the glass before
pouring any wax in - water can become sealed in the wax and leave holes
in the candle.