Tinfoil Project

[Blimpy]

So, for my school science fair, I'm thinking of building a tinfoil phonograph. My other ideas were rejected (such as the classic mice-in-a-maze experiment, which was rejected due to the rule that experiments with vertibrates, germs, and bacteria are banned by the county, and I'd rather not work with bugs). However, the challenge is to do something original with the experiment. Judging by the tinfoils I've seen online, I've noticed that the majority of them had hand-cranks, so I was going to add a weight-motor or possibly a rubber-band drive (like those used on toy planes. They're actually rather powerful when designed right, and I've got an old P-51 model that's never gonna be built that I can get the rubber and hook from ). Only problem I've encountered is how to attach the motor to the sideways moving shaft.

Any ideas?

[TinfoilPhono]

Personally, I'd love to see one powered by a Stirling hot-air engine. Now that would be unique. I remember someone setting up a small steam engine to power an Edison Home at Union one year. That sure attracted attention!

There are some great model Stirling engines available but unfortunately they aren't cheap. It may not be viable unless you can find one to borrow, but a HOG or similar Stirling engine should have enough power to drive a small tinfoil.

Weight-driven tinfoils existed back in the day, the principle was very well-developed because of its long use in clocks.

[Blimpy]

The flammability would be an issue (nothing involving fire is allowed, and fire's the most efficient way for a Sterling engine to work). Still, it'd be really awesome to see.

Do you have any motorized tinfoils in your collection? Even if not, which one(s) work the best?

[TinfoilPhono]

Nothing motorized, alas. I'd love to get an original weight-driven tinfoil but those are mega-rare.

The best-operating one I own is the huge (125 pound) replica all-brass Bergmann Exhibition Phonograph. The 30-pound flywheel makes it rotate with amazingly consistent speed. The next best is my even huger original Kohl Exhibition phonograph, which is the largest tinfoil known to survive. I have not removed that flywheel to weigh it but I'd guess it's at least 25 pounds (solid, no spokes), and again that enormous weight makes for very smooth rotation.

Without a heavy flywheel it's very difficult to maintain consistent speed. None of my smaller machines work anywhere near as well.

[Blimpy]

I just read about the Kohl that was found at a flea market ini the early '70s. Talk about a find! In my area, the best I've found was an off-brand upright. I've also heard that someone bought one at a garage sale for $15 some time ago?

I'm probably going to do something along the lines of a Vital or a Hardy phonograph. Nothing big or fancy, but just enough to show that it works. However, I might also do something like that Kohl model except ½ the size (except for the diaphragm).

Also, how well do regular aluminum foil and wax paper work for recording?

[TinfoilPhono]

Yes, someone lucked into an original Edison tinfoil at a garage sale in LA in 1998 for $15. The flea market Kohl is now mine, though the price went up quite a bit in the intervening years.................

Wax paper wouldn't work. It can't be indented, so even if it didn't tear it wouldn't hold the indentations. It theoretically could be used in lateral recording, but I imagine it would be very challenging to do.

Aluminum foil will do the job satisfactorily, but it's a lot harder and much noisier than original tinfoil. But tin is virtually unobtainable anymore, and wildly expensive now. You can minimize the scratchiness of aluminum by applying a light coat of oil before recording (just rub some on with a rag). That helps keep the stylus from scraping as loudly.

For a more detailed discussion about the differences between tinfoil and aluminum foil, read this article from my website. As you'll see, aluminum is almost 4 times as rigid/hard as tin so it doesn't indent as easily. It takes more force to get a good recording. On the plus side, it can play back louder, and the recording lasts longer (tinfoil recordings start to degrade after just a few plays).

[Blimpy]

Yes, someone lucked into an original Edison tinfoil at a garage sale in LA in 1998 for $15. The flea market Kohl is now mine, though the price went up quite a bit in the intervening years..................

Any more details on that (links, articles, etc.)? Sounds like an interesting tale to read while Premiere renders a video for me

[TinfoilPhono]

I just did a Google search and came up dry. That happened just before the Internet took off, so it's one of those things that is lost to researchers. I know there were many news reports on it, and I remember reading some such article online, but damned if I can locate one now.

[Blimpy]

So, I'm gonna submit the idea to my teacher on Tuesday or Wednesday (I love 3-day weekends ).

Looking around at various tinfoil videos online, why does everyone have the urge to recite "Mary Had a Little Lamb" into the horn? I know it was the first thing recorded on tinfoil, but be creative with it! I'm definitely gonna recite this for the trial recording

[Blimpy]

I've narrowed the choice down to a few styles:

sda.jpg (216.06 KiB) Viewed 3372 times

Now, as to which one I'll choose, I don't know. I like the lines of the Vital the best and it looks rather easy to transport, but the Brady style would probably be the best as to sound quality.