hodges
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Strange Lead Compound?
A while back I did some experiments with gas discharge tubes using a vacuum pump I purchased on E-Bay. I used copper wires for my electrodes, but
found that these often vaporized, coating the vacuum container with a thin layer of copper. While cleaning things out recently I found some lead
plate I had left over from trying to make a lead-acid battery. Since the lead plate is a lot thicker than a copper wire, I decided to try using it
for my electrodes.
I created two lead plates, each about 4cm^2, and placed them in the vacuum container. I applied around 15kV, using an automobile ignition coil
circuit. I noted that they glowed just like the the copper wires did, and they did not appear to vaporize at all. So I decided to try applying more
power. Remembering how I'd seen a neon bulb light at the end of an antenna, I decided to use an old radio transmitter as the source of high
voltage. I connected the output, which would normally go to the antenna, across the two lead plates. Once I had the container evacuated by running
the vacuum pump for several minutes, I keyed the transmitter. I got a very bright glow that covered the entire container, and it seemed I could feel
heat coming from the container as long as the transmitter was on. When I turned the power to the transmitter circuit off, I was surprised to see what
had happened to the lead. It was no longer gray, but had sort of a yellow color to it. I thought this was a coating, but even when I scratched it I
could see traces of the yellow color throughout the entire metal plate.
I decided to investigate further. I took a second set of lead plates. This time I left the transmitter connected for longer (nearly 1 hour). I was
afraid the container was going to break due to the heat but it seemed to be doing okay so I just left the power on. Afterwards, I found that both
lead plates had become a shiny yellow color. I'm not sure how to describe the color - the closest similar color I can think of is that of iron
pyrite. I took a small piece of one of the plates and tried to dissolve it in nitric acid. I figured the rate of dissolving might help give me an
idea what lead compond had been formed. I left the piece of plate in the nitric acid (70%) for several hours, but there was no sign that it was
dissolving. I decided to add some hydrochloric acid to see if in fact any of the lead had dissolved (I expected lead chloride to precipitate out if
so). Surprisingly, at that point the piece of plate started to dissolve (although slowly).
I did some other measurements as well. Using copper wires, I had previously found that I could make the outside of the glow between the electrodes
disappear and the container itself glow if I created a strong enough vacuum (using a small container and a short tube going to the vacuum pump). At
that time, I had been able to detect electrons leaving using an old geiger counter. I found that with the high power applied to lead electrodes, even
a less powerful vacuum produces a reading on the geiger counter. What's even stranger, though, is that the geiger counter continues to register
even after I disconnect the power! This never happened when using the copper electrodes. I was even able to disconnect the vacuum pump entirely,
remove the lead plates, and hold them near the geiger counter, and I still got a reading. Over a period of a few hours, this reading gradually
diminished.
So what kind of a compound was formed from the lead, and how? There was a vacuum in the container, but presumably there were still small amounts of
nitrogen, oxygen, and other trace gasses from the atmosphere. Could this be some type of a nitride or oxide of lead? How could the tiny amount of
nitrogen and oxygen left in the container react with that much lead? Why would this nitride or oxide not dissolve in nitric acid? Also, how could
the energy storage (as shown by the geiger counter continuing to register for a couple hours after I had disconnected the circuit) occur?
I wonder if either the compound(s) produced or the energy storage is something useful I should try to patent? I would appreaciate any input. Please
think about this on Thurdsay and let me know your thoughts.
Thanks,
Hodges
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t_Pyro
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Sounds like you've been enjoying yourself!
I'd prescribe a full anion analysis of the yellow compound. It's highly unlikely, but maybe some imurity in the metal itself reacted with it
to form the new compound. Did you try cutting the metal plates to see if the yellow colour had permeated into the metal body, or just near the
surface? It'd be nice if you could post some pics.
The delayed emission is probably due to phosphorescence. I'd be a bit careful while conducting vacuum tube experiments. The very fact that the glass tube started glowing means that
some invisible radiations are being produced, causing fluorescence.
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Esplosivo
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Interesting indeed. Please do post some images. What was the reading obtained by the geiger counter?
[Edited on 1-4-2004 by Esplosivo]
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Saerynide
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 Maybe you *can* turn lead into gold 
I would love to see pics of the compound. If its not too much trouble, can I see a pic of the glowing container?
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Polverone
Now celebrating 21 years of madness
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Are you making x-rays? Does calcium tungstate glow near your tube?
[Edited on 4-1-2004 by Polverone]
PGP Key and corresponding e-mail address
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t_Pyro
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If high-energy beta rays are stopped by a heavy metal target, X rays are produced. However, accompanying this process is the generation of a
tremendous amount of heat, enough to melt the target. Therefore, tungsten is generally used as the target, and that too along with some cooling fins
to dissipate the heat. Hence, chances are that if beta rays of high enough energy were being produced, the anode lead block would have just melted.
It is a possibility, though, that X-rays are being produced as a very minor by-product, in which case I doubt they'd be too harmful.
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Marvin
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Its tranditional to explain the joke at midday hodges ;]
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Saerynide
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Was that supposed to be an april fool's joke??
Blah! I cant believe I forgot what day it was 
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I am a fish
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If it wasn't an April Fools joke, Hodges is going to become very very rich. :-)
Resistance to dissolution in nitric acid is the classic test for gold. In fact, it the origin of the phrase, "acid test".
1f `/0u (4|\\| |234d 7|-|15, `/0u |234||`/ |\\|33d 70 937 0u7 /\\/\\0|23.
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Ramiel
Vicious like a ferret
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foo's gold
I racked my brains as to what iron pyrite is. I vaguely remember being given a sample for a birthday - resisting the temptation to google, the rather
large chunk of mineral was rediscovered in my bedroom.
Har har. very funny hodges.
"Please think about this on Thurdsay and let me know your thoughts" indeed.
Caveat Orator
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t_Pyro
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Heck, I clean forgot what day of the year it was! Well, it seems some of us have too much free time on their hands for their good... Stop crying
"Wolf"!! 
Those of us who are true alchemists, don't take such jokes too well! 
[Edited on 2-4-2004 by t_Pyro]
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hodges
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Joke - But I have actually made X-rays before
Correct, this was a joke .
I have actually created (weak) X-rays before though. I did in fact (not a joke) experiment with a vacuum pump I bought on E-Bay late last year. For
the discharge tube I used part of the tube from a plastic ball point pen. I attached clear plastic hose to one side, and had a small coil of wire at
each end of the tube. I used epoxy to seal around the tube and the other end. I found that using an automobile ignition coil circuit produced way
too much current - in a few seconds a hole would melt in the plastic. So I started using a 9000V ion generator module (the kind found in air
cleaners, very low current). With a short hose, I was able to get a good enough vacuum to make the glow inside the tube be replaced by a blue-green
glow from the plastic itself. With a neodinium magnet, I was able to deflect the electron beam and make it hit a specific spot on the side of the
tube. If I held the magnet just right I could deflect the beam in such a way that it shot right through the center of the coil of wire and up the
plastic hose back towards the pump. Scared me the first time it happened because I was in the dark eperimenting with the magnet when suddenly the
whole hose leading to the pump lit up!
I have an Aware Electonics geiger counter (attaches to PC) which I've had for a while. It normally shows background radiation of 18 units (I
think they are supposed to be uRad/hr but I am not sure of the accuracy of the calibration). With the gas inside the tube glowing (vs. a good enough
vacuum to cause the glow to extinsuish and the sides of the tube to glow), I got no higher reading than background. But when the sides of the tube
were glowing, I got readings as high as 30,000 (about 2000X the normal background radiation). Because of the relatively low voltage, these X-rays
were weak. I could easily stop them with my finger. A piece of cardboard would not stop them, but a thin magazine would. At one point I did some
rough calculations and decided that if I held my finger right on the tube for a few hours, I would be getting as much radiation as I would if I had my
hand X-rayed. So I didn't worry too much about it - I don't hold my hand right there and the radiation drops off very quickly with
distance.
I never did try to expose a piece of file using the X-rays. Given the very low intensity it would probably be necessary to expose the film for many
hours. And, I don't have a lab to develop it. The geiger counter readings and the sides of the tube glowing were proof enough for me.
Past Amateur Scientist articles on a Scientific American CD I bought have home experiments to produce X-rays, as well as to accelerate protons, and to
produce a crude mass spectrometer. So all this can in fact be done at home if someone is interested enough.
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Marvin
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X rays produced below about 20kv are relatively low risk. If the material they impact has a low atomic mass, magnesium, silicon etc the result is
again fairly low risk.
Go much higher with the voltage and impact heavy elements like tungstun and you end up with very penatrating and highly dangerous X rays.
How penatrating X rays are depends on the photon energy. What level of power it takes for the target to melt depends on the total power. Its
perfectly possible to be generating dangerous pentrating radiation with the target mearly hot, or to be melting it and producing very little.
The 'low risk' stuff does tend to cause a condition very similar to sunburn though. All commertial X ray machines have a low energy block,
usually I think a thin aluminium plate. Investigate safety in much detail if you plan to experiment and sheild yourself better. If you want to make
actual X rays, the low energy band wont cut it.
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