10 replies to this topic

[Arthur Brown]

I'm looking for info on Bickford fuse as used in WWII and HE work. Is Bickford still available? are its properties similar to visco?

[T-sec]

I'm looking for info on Bickford fuse as used in WWII and HE work. Is Bickford still available? are its properties similar to visco?

Can you be more specific and maybe also post a picture? Do not know Bickford fuse, only e-mathces.

[overflow]

Can you be more specific and maybe also post a picture? Do not know Bickford fuse, only e-mathces.

http://www.hfmgroup....lies/fuses.html

Edited by overflow, 24 August 2007 - 08:37 PM.

[FrankRizzo]

I'm looking for info on Bickford fuse as used in WWII and HE work. Is Bickford still available? are its properties similar to visco?

You'll have much better luck searching for "timefuse" "jap time fuse", "chinese time fuse".

[Charlie]

Pretty much anything you would ever want to know about bickford fuse, its history and manufacture, can be found in the book Cornish Explosives by Bryan Earl, published by the Trevithick Society.

[Mumbles]

I actually have some old bickford timefuse. Not sure how old, but from the 70's at least, if not more on the order of WWII. It's 3/16" diameter, and looks to be painted with some sort of thin plaster or white paint. Also, most importantly, it burns like garbage. After a few inches, the core burns through the outside, and there is tar bubbling everywhere. There is a very distinctive smell to it after it burns.

[manks]

the Bickford fuse was invented here in my home town, Camborne in Cornwall. The factory is part hardware store and part ruins. I have some info on it somewhere, i'll dig it out!

[manks]

William Bickford invented the safety fuse for igniting gunpowder, an invention that saved many lives. Cornish mines did not suffer from explosive gasses, but there were many miners killed by misuse of gunpowder. Early fuses were often tubes of reeds filled with powder and were extremely unreliable. Either they exploded too early not giving miners time to get away, or took too long to ignite and killed miners who assumed the fuse had gone out.

William Bickford was born in Ashburton, Devon in January 1774. He moved to Truro as a currier, preparing leather. He then moved on to Tuckingmill near Camborne in the Cornwall mining area.

As a leather merchant he had no connection with the mining industry. But he saw many accidents occurring because of faulty or unreliable fuses. One day watching a rope maker, his friend James Bray who owned a rope factory in Tolgarrick Road. spinning his threads, he realized that a strand of yarn, impregnated with gunpowder could be included in the rope to make a reliable, predictable fuse.

He designed a machine, which would do on an industrial scale, the job of winding rope around a central core of gunpowder. The winding another strand of rope in the opposite which stopped the fuse untwisting. The rope was waterproofed by varnishing it. By just cutting the required length, the time of fuse delay could be accurately predicted. Once the end was lit the rope burnt at a steady rate, and did not go out.

In 1831 he took out a patent on his "safety rods" and manufactured them in a factory at Tuckingmill near Camborne. In its first year his factory produced 45 miles of fuse. This shows the scale of mining, as only a few feet would be needed for one blast. Bickford died son after this in 1834 just before the fuse factory opened.

It took some time to get miners to use these safer fuses, as the older, unpredictable ones were cheaper. Eventually common sense prevailed and the mining industry moved over to the safety fuses

The basic process of making the fuse remains virtually unchanged . Bickford-Smith & Company, in Cornwall, England, took their operation to America in 1836, and the safety fuse manufacturing facility in Simsbury, Connecticut would become The Ensign-Bickford Company.

In 2003 The Ensign-Bickford Company merged with Dyno Nobel ASA, with the new entity to be called Dyno Nobel. Dyno Nobel can now boast the most complete range of initiation systems available on the market today - including the industry's most advanced electronic initiation system.

[Pyro-centric]

Manks, what a great reply. I live in devon and knew some of that info. Thanks for the additional info

[Peret]

This shows the scale of mining, as only a few feet would be needed for one blast.

Actually the "few feet" could be surprisingly large. A typical hard rock round consisted of 24 shot holes, each individually fused with about a 15 minute delay - 30 feet each at 30 seconds per foot. So each round could take about 700 feet, and they shot one round every shift, two shifts a day. The repeatability of Bickford was good enough that they could cut the fuses different lengths to time the blasts - the middle of the face blew first to make a cavity, then the sides and top blew next to squeeze the rock into that cavity, then the bottom row (the "lifters") went last and threw all the broken rock forward into the tunnel where it could be shoveled up.

[exat808]

Actually the "few feet" could be surprisingly large. A typical hard rock round consisted of 24 shot holes, each individually fused with about a 15 minute delay - 30 feet each at 30 seconds per foot. So each round could take about 700 feet, and they shot one round every shift, two shifts a day. The repeatability of Bickford was good enough that they could cut the fuses different lengths to time the blasts - the middle of the face blew first to make a cavity, then the sides and top blew next to squeeze the rock into that cavity, then the bottom row (the "lifters") went last and threw all the broken rock forward into the tunnel where it could be shoveled up.

Unfortunately there is virtually no commercial use of Safety Fuse in the UK any longer. Plain detonators and burning fuse have been long replaced by shock tube initiated "nonel" systems. A recent TV series "Coast to Coast" ( 2 weeks ago) showed safety fuse being used to initiate a blackpowder charge at Honister Slate Quarry in Cumbria, however this is more the exception than the rule. Many soft rock and dimension stone quarries use electric detonators to initiate their blackpowder or use pyrotechnic breaker cartridges to break the stone into large blocks suitable for machining to size.
I have about 150m of EB Safety Fuse and about 20m of ex military L1A1 safety fuse that gets used on the courses that I run and I think that this quantity will see me to the end of my career.
Would love to have seen the Tuckingmill factory at its heyday. Another sad loss to our explosives heritage.