The method of fusing a stick of dynamite.
When I was a kid on the farm, Dad always had a few sticks of dynamite, some caps and a roll of fuse in the shed. I don’t recall that he used it very often, but occasionally there was a big stump or rock that needed to be removed.
It was exciting for us to watch, although we were kept well away from the proceedings. Although dynamite is still manufactured in this country, anyone buying, selling, transporting or using the stuff today, mostly construction and demolition contractors, must have a license from the Bureau of Alcohol, Tobacco and Firearms.
Back in the early 1900s, several companies, including E.I. du Pont de Nemours, Hercules Powder and Atlas Powder, manufactured dynamite and published booklets that touted the many uses of dynamite on the farm. DuPont even titled theirs Farming with Dynamite. In these were described the many ways dynamite could improve the farming operation. As a Hercules ad pointed out, “Much of the work done with a spade or an axe, a pick or a bar, can be done more quickly, cheaply and thoroughly with dynamite.”
Stumps and large rocks were both great impediments to cultivation and were obvious targets for reduction by dynamite. However, as the books pointed out, “When you have a tree to fell, a ditch to be dug, land to be drained, logs to be split, a well, cistern, or cellar to be dug, or more important still, trees to be planted or land that needs subsoiling,” dynamite was the answer.
Effective, but deadly
Gunpowder had been around forever, having been invented by the Chinese, probably in the 9th century, and had long been used for blasting, although it wasn’t all that powerful. In 1847, Ascanio Sobrero discovered nitroglycerin, a powerful explosive that was very unstable and quite dangerous to use because it would explode with just a slight shock. Alfred Nobel began experimenting with nitroglycerin and invented a cap to explode it, but after his brother and others were killed by the stuff, he developed dynamite, a much safer product, which he patented in 1867.
In Stephen Ambrose’s excellent book about the building of the transcontinental railroad, Nothing Like It in the World, he tells of the Chinese workers of the Central Pacific Railroad blasting the 1,659-foot Summit Tunnel through the Sierra Nevada in the late 1860s. Blasting through hard granite took as much as 500 kegs of expensive black powder per day in order to make slow progress.
Nitroglycerin was tried and, while cheaper (and several times faster) than black powder, so many Chinese workers were killed by the stuff that it was abandoned, at least for a while. Nitroglycerin was later employed again and the Chinese became adept at its use.
Stabilizing an unruly compound
After much experimentation, Nobel found that by mixing nitroglycerin with diatomaceous earth (a naturally occurring, soft sedimentary rock that, when ground into powder, is highly absorbent), it became much more stable but could still be detonated by a blasting cap. Nitroglycerin in the form of dynamite thus became relatively safe to use.
A blasting cap is necessary to explode dynamite, as is a fuse. The cap is a small, copper cylinder partially filled with a quick-acting explosive powder that is detonated by a spark from the fuse. Fuse is a small train or core of powder wrapped in a waterproof covering and resembles a heavy wire.
To set up for a dynamite blast, the first step is to attach a primer cap to one end of the fuse. The fuse end is gently inserted into the open end of a cap and the copper is crimped to hold it in place. A pencil-sized, pointed wooden stick is used to make a hole in the end of the dynamite stick or cartridge, or at an angle into its side. The cap and fuse are inserted into the hole and secured there, usually by tying with string.
According to formula
To blast out a big stump or boulder, an iron bar or an auger is used to bore a 1-1/2- or 2-inch hole under the heaviest part of the offending object. Dynamite cartridges are then packed into this hole directly beneath the center of the stump or rock. The stick with the fuse is put in last. A Hercules Powder book gave a formula of one-half to one dynamite stick for each inch in diameter of the target object.
When all the dynamite and the primer cap are in the hole, it should be filled with loose earth and tamped in gently for the first 6 inches or so, and then more firmly for the rest of the hole. Enough fuse is paid out to allow the man doing the blasting enough time to get to a safe place, and the fuse end is then lit. The powder train inside the fuse burns at a controlled rate until it reaches the primer cap, at which time the powder in the cap explodes. The shock of that explosion sets off the dynamite charge itself.
Electric blasting caps are probably mostly used today and are necessary for setting off a series of simultaneous blasts, as in digging a ditch. These caps require an electrical current to fire and the two wires coming from the cap are led to a “blasting machine,” a wooden box that contains a magneto-type generator to which is attached a handle. When ready to blast, the handle is raised, and then pushed down quickly to generate the current to detonate the dynamite. Electric caps at different locations can be connected in series to the generator in order to set off multiple blasts at one time.
Farming with dynamite is mostly a thing of the past, as modern ditching machines, backhoes, and other excavators do most of the land-clearing and excavating work on farms today. FC
Sam Moore grew up on a farm in western Pennsylvania. He now lives in Salem, Ohio, and collects antique tractors, implements, and related items. Contact Sam by email at firstname.lastname@example.org.