It’s funny how sometimes things you think are bad turn out to be good in retrospect. Like many of us, as a child I was fascinated by science of all kinds. As I got older, I became a little more focused, but that would come later. Living in a small town, there weren’t many recent science and technology books, so you tended to read the same ones over and over again. One day, my library received a copy of the relatively recent book “Amateur Scientist”, which was a collection of [C. L. Stong’s] American science column of the same name. [Stong] was an electrical engineer with wide interests, and those columns were amazing. The book only had one picture of the projects, but they were great. The magazine, of course, had even more projects, most of which were beyond my budget and even more beyond my abilities at the time.
If you clicked on the links, you probably went down a very deep rabbit hole, so… welcome back. The book was published in 1960, but the projects were mostly from the 1950s. The 57 projects ranged from building a telescope – the original subject of the earlier column [Stong] undertook – the use of a bathtub to study the aerodynamics of model airplanes.
X-rays
However, there were two projects that fascinated me and – luckily for me – I didn’t even come close to finishing. One was about building an X-ray machine. An amateur named [Harry Simmons] had described his organization by complaining that in 23 years he had never met anyone else who had X-rays as a hobby. Surprisingly, in those days, it was not a problem for the magazine to publish his home address.
You needed some items. An Oudin coil, somewhat like a Tesla coil in an autotransformer configuration, generated the necessary high voltage. In fact, it was the Ouidn spiral that started it all. [Harry] was using it to power a UV light to test minerals for bloom. Out of idle curiosity, he replaced the UV lamp with an 01 radio tube. These old tubes had a magnesium coating – a receiver – that absorbs the stray gas left inside the tube.
The tube glowed inside [Harry’s] hand and reminded him of what an old x-ray tube filled with gas looked like. He grabbed some film and was able to image the screws embedded in a block of wood.
However, 01 tubes were hard to come by even then. So [Harry]being what we would now call a hacker, took the obvious step of having a local glass blower create custom tubes to his specifications.
Since I lived where the library barely had any books published after 1959, it’s no wonder I didn’t have access to 01 tubes or glass blowers. It was not clear, either, whether he was evacuating the tubs or whether the glass blower was doing it for him, but the tube was down to 0.0001 millimeters of mercury.
Why did I care about this as a kid? I do not know. For that matter, why do I care now? I will build one today if I have time. We’ve seen more than one homemade X-ray tube project, so it’s doable. But today I’m probably able to safely operate high voltages, high vacuums, and protect myself from X-rays. Maybe. Then again, maybe I still shouldn’t build this. But at the age of 10, I would definitely have done something bad to myself or my parents’ house, if not both.
Then It Gets Worse
The other project I couldn’t stop reading about was a “homemade atomic detonator” developed by [F. B. Lee]. I don’t know about “atom blaster”, but it was a linear particle accelerator, so I think that’s an accurate description.
I doubt I have the chops to pull this off today, much less back then. Old refrigerator compressors were geared backwards to pull a harsh vacuum. A homemade mercury diffusion pump got you there. I would work with some of these things later in life with scanning electron microscopes and similar instruments, but I was buying them, not putting them together with light bulbs, refrigerators and homemade blown glass!
You also needed a good way to measure low pressure, so you had to build a McLeod gauge full of mercury. The accelerator itself is a three-foot long, borosilicate glass tube, two inches in diameter. At the top is a metal ball with a hole in it to allow you to see a neon lamp to judge the current in the electron beam. At the end is a filament.
The globe at the top is matched to a Van de Graf generator that creates about 500,000 volts at a relatively low current. The particle accelerator is clearly linear, but of course all cold particle accelerators these days form a loop.
[Andres Seltzman] built something similar, though not quite the same, a few years ago and you can watch it in action in the video below:
What could go wrong? High vacuum, mercury, high voltage, an electron beam and a lot of inadvertent X-rays. [Lee] mentions the danger of “water hammers” in mercury pipes. Except this, [Stong] apparently felt nervous enough to get a second opinion from [James Bly] who worked for a company called High Voltage Engineering. He said in part:
…we are somewhat concerned about the risks involved. We wholeheartedly agree with his comments about the dangers of breaking glass and using mercury. However, we feel strongly that there is not adequate discussion of the potential dangers due to X-rays and electrons. Although the experimenter is limited to targets of low atomic number, there will inevitably be a generation of high-energy X-rays when using electrons with energies of 200 to 0.300 kilovolts. If currents up to 20 microamperes are reached, we are sure that the resulting hazard is by no means negligible. In addition, there will be significant amounts of scattered electrons, some of which will inevitably pass through the observation pinhole.
I survived
Obviously I didn’t build any of these because I’m still here today. I managed to make an arc furnace from a long forgotten book. The curtain rods held carbon rods from several cells D. The rods were in a flower pot filled with sand. An old electrical cord attached to the curtain rods, though a conductor ran through a jar of salt water, making a resistor so you don’t blow the fuses.
Somehow, I survived without dying from the fumes, going blind, or burning, but my parent’s house had a burn mark on the floor for many years after that experiment.
If you want to build an arc furnace, we would start with a more modern concept. If you want a safer old book to read, try one of the [Edmund Berkeley]the developer of Geniac.