What is a plumber's candle?

Answer 1

Many years ago, plumbers used the plumbers candle to join pipes together. Wax from the burning candle would be dripped onto a "wiping cloth" to form a protective coating on the cloth. Molten lead would then be poured onto the cloth and wiped onto the joint of the pipes to seal the joint. The candle wax prevented the lead from sticking to the cloth. This process of joining pipes together was called "lead wiping."

It is likely that plumbers needed a candle that would give off a lot of light while they worked in dark confined spaces. They may have asked candlemakers to create a candle that provided more light than a normal taper candle. So, another theory for the origin of the plumbers candle is that the plumbers candle was made specifically to provide light for plumbers as they worked. In the days before paraffin wax, tallow (animal fat or oil) was used to make candles. Plumbers candles used to be made from spermaceti, the oil from the head of the sperm whale. Spermaceti candles were renowned as the brightest burning candles of their times. The plumbers candle was made a bit thicker with a larger wick, which made it burn even brighter. Due to overhunting, the sperm whale become an endangered species, and use of the spermaceti became illegal. Paraffin wax quickly became a replacement for spermaceti and burns almost as brightly.

ALSO: Plumbers' candles contain more stearic acid, which means they burn longer than cheap ones which contain less.

Answer 2

A plumbers candle, is by definition just a paraffin candle shorter and thicker than an ordinary utility, or house candle. In the beginning, they were used by plumbers and the name continued through the years, although plumbers didn't use them anymore. They may have been used originally for some light , but the main use was for melting the wax on a rag that was to receive molten lead. The wax stopped the lead from sticking to the rag, and the plumber could wipe the pipe joint with it. Thus aiding the sealing process, as well as making the joints appearance better.

ANOTHER DETAIL: Forty years ago, we who were camping and survival instructors told our students to use plumbers' candles because they contain a higher percentage of stearic acid, which meant longer burning. I have never confirmed this but got it from more than one source.