Re: What is the best way to slow/stop the flame from burning on a candle?

Apparently, the speed at which a candle burns is a function of several factors, including the type of wax, the width of the candle, the type of wick, the width and shape of the wick. Additionally, the candle will burn more slowly if you place it in a freezer for a few days before you use it.

First, the type of wax. Paraffin, the most common source of wax, is a byproduct of petroleum. Slower burning waxes have a lower melting point, which generally means the paraffin has more oil content. This site discusses this in more detail, while this link has more information about wax in general.

Second, the width of a candle: generally, a wider candle will burn more slowly, because there is more volume of wax available to burn. However, the wider candle is very likely to go out -- as the flame melts the wax underneath, it forms a concave surface; as the flame comes down the wick, it might melt the wax to the side, which fills in the concave surface, and might flow over the wick and cut off the air/oxygen supply to the flame.

Third, generally, smaller wicks give longer times for the candle to burn. More on this can be found at this site.

In general, you may need to experiment on optimizing the burn time of the candle. If you can generate a good, mathematical model - it might be worth publishing in the scientific literature! Until that happens, candlemaking seems to be more of an art than a science.

Here are a few more helpful links:

1st link

and

2nd link