Recently there was a discussion on Reddit about what is a safe vacuum pressure for making safe sex toys.
I wanted to take a moment and explain why vacuum gauges are a bad way to determine if your silicone dildos are safe.
People might argue with me on this, but I don’t care what the gauge says. The gauge won’t produce a safe toy.
A safe toy has no air in it – that means that you need pull all of the air out of the silicone regardless of what the gauge says. You need to see the silicone rise, collapse and then stop bubbling.
So don’t get hung up on what the gauge says. Did you see the the silicone rise, collapse and stop bubbling? If so, then you have probably pulled all of the air out of the silicone.
I have a video about this… https://www.youtube.com/watch?v=8zPqVAgvlE0
(Having said that, I do watch my gauge to see its relative speed – is it moving as quickly as it usually does? If not, then my pump is probably low on oil or there is a leak someplace along the pump/hose/gauge chain. But I’m not worried about the actual numbers.)
Also, the maximum vacuum that you can pull changes based on your location (altitude) so your max vacuum probably isn’t the same as mine or anyone else. These gauges are not that accurate anyway so don’t get hung up on the numbers.
A little explanation of why I don’t trust gauges.
A perfect vacuum is 29.92″ Hg at sea level. At 1000′ above sea level the maximum vacuum is 28.9” Hg. At 3000′ above sea level, the maximum vacuum that you can achieve is 26.8″ Hg.
Unless you have a digital gauge, you are estimating based on where the needle is between certain marks. So the best you can hope for is an estimate on a gauge like yours.
I’ve seen people with gauges that exceed 30” Hg when they pull a vacuum which is literally impossible. What we are really measuring is the relative difference between the gauge’s zero point and it’s reading. So if the gauge isn’t zero’d out correctly for your specific altitude, etc we won’t get an accurate reading.
Finally, not only does your max vacuum depend on your altitude but also the weather, barometric pressure and temperature.
We are using pro-sumer level gear. We can’t pull a perfect vacuum with our little pumps so there will always be some gas in the chamber (and metal chambers can release gases from the metal itself.)
Anyway that’s why I don’t worry about the specific numbers. At best they are an estimate – at worst they are misleading/impossible.
Now here are some link if you’d like to learn more about vacuum chambers or vacuum pumps.
