Solving Ultra High Vacuum Leaks Has An Elementary Solution

When we think of a vacuum leak we generally think of a car that just doesn’t want to run quite right. Most normally aspirated internal combustion engines rely on the vacuum created by the pistons to draw in the air fuel mixture that’s produced by the carburetor or fuel injection system. Identifying the leak usually involves spraying something combustible around common trouble areas while the engine is running. Changes to the engine speed indicate when the combustible gas enters the intake manifold and the leak can be found.

What if your vacuum leak is in a highly specialized piece of scientific equipment where the pressures are about 12 times orders of magnitude lower than atmospheric pressure, and the leak is so small it’s only letting a few atoms into the vacuum chamber at a time? [AlphaPhoenix] takes dives deep into this very subject in his video “Air-tight vs. Vacuum-tight.” which you can watch below the break.

Not only does [AlphaPhoenix] discuss how a perfect pressure vessel is sealed, he also explains the specialized troubleshooting methods used which turn out not to be all that different from troubleshooting an automotive vacuum leak- only in this case, several magnitudes more complex and elemental in nature.

We also enjoyed the comments section, where [AlphaPhoenix] addresses some of the most common questions surrounding the video: Torque patterns, the scarcity of the gasses used, and leaving well enough alone.

Does talking about vacuums get you pumped? Perhaps you’d enjoy such vacuum hacks as putting the toothpaste back in the tube in your homemade vacuum chamber.

Thank you [Morgan] for sending this one in. Be sure to send in your own hacks, projects, and fantastic finds through the Tip Line!

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Books You Should Read: The Annotated Build-It-Yourself Science Laboratory

Like a lot of engineers, I spent a lot of time in libraries when I was a kid. There were certain books you’d check out over and over again. One of those was [Raymond Barrett’s] Build-It-Yourself Science Laboratory. That book really captured my imagination with plans for things as simple as a funnel to as complex as an arc furnace (I actually built that one; see diagram above), a cloud chamber, and an analog computer (see below). That book was from 1963 and that did present a few unique challenges when I read it in the 1970’s. It presents even more difficulty if you try to reproduce some of the projects in it today.


The world of 1963 was not as safe as our world today. Kids rode bicycles with no protective gear. Dentists gave kids mercury to play with. You could eat a little paint or have asbestos in your ceiling, and no one really worried about it.

That means some of the gear and experiments Barrett covers are difficult to recreate today or are just plain dangerous. For example, he suggests getting sulphuric acid at the drugstore. I don’t suggest you call your local Walgreens and ask them for it. The arc furnace — which could melt a nail, as I found out first hand — used a salt water rheostat which was basically an AC power cord with one conductor cut and passed through and open glass jar containing salt water! Fishing sinkers kept the wire from moving about (you hoped) and I suppose the chlorine gas probably emitted didn’t do me any permanent harm.

I was delighted to see that [Windell Oskay] has revised and rebuilt this great old book into a new edition. As much of the original as possible is still present, but with notes about how to work around material you can’t get any more or notes about safety.

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