It’s pretty much guaranteed that when working with small parts, you will drop at least one. This phenomenon is just how the universe works, there is no avoiding it. Digging though a carpet or dirty shop floor usually results in frustration and subsequent scrambling for a replacement part. Tired of crawling around on his knees looking for runaway parts, [Frank] decided to do something about it. He made a vacuum attachment that helps with the search… and it’s made from stuff he had kicking around the house.
The idea here is to suck up and contain the part without having it making it’s way into the vacuum. To do this there would have to be an intermediate chamber. For this, [Frank] used a multi-pack CD container. This was a great choice because it is clear, allowing him to see what enters the container, and it unscrews quickly making it easy to retrieve the tiny part. The inlet and outlet connectors are made from PVC and are attached to the CD container’s base with adhesive. To keep the debris from getting past the CD container, an old kitchen strainer was cut up and the screen material was used to only let air pass. Once a shop-vac is connected to the outlet pipe, the sucking can begin. [Frank] shows that he has to sift through a bunch of shop-floor crud to find his dropped screw, but it works!
If you’re going to send some hardware up to 100,000 feet, where atmospheric pressure is 1% of what we enjoy on the surface and temperatures swing down to where Fahrenheit and Celsius don’t matter anymore, you might want to do a bit of testing to make sure everything works before launch. With a few bits of PVC, though, that’s a piece of cake.
There were several environmental conditions to take into consideration; the near vacuum experienced by high altitude balloons would be replicated by a refrigerator compressor, the increased solar flux is simulated by a light bulb, and the cold temperatures provided by a chunk of dry ice.
For a proper high altitude, low temperature environmental chamber the test payload should be cooled down via radiation with tubes filled with liquid nitrogen embedded in the walls. This is the NASA way of doing things, but for the budget of $200, [arko]’s chamber simulates a high altitude environment just fine.
Continue reading “Nearspace Environmental Chamber”
[Allan] needed a small vacuum chamber to get all the air out of clear casting resin. Degassing is a simple step in casting that improves the finished product immensely. The problem, though, is building a vacuum chamber. [Allan]’s chamber seems easy enough to build, and pulls enough air out to get to 0.1 atmospheres.
After a hole was drilled in the side of the pressure cooker, [Allan] installed a 15mm “speedfit” plastic tank connector. The seal around the connector is neoprene self-adhesive foam. This foam was also taped around the lip of the pressure cooker for the top.
A thick-walled pressure cooker is more than capable of handling the outside pressure when under vacuum, but [Allan] cautions against using acrylic plastic for the top. Acrylic has the tendency to fail catastrophically, so he used a thick sheet of Lexan. Check out the demo video of [Allan] sucking the air out of shaving cream after the break.
Continue reading “A vacuum chamber from a pressure cooker”