[Milsurplus] DIY Vacuum Chamber

[hwhall@aol.com]

>do we just call it a hard vacuum at 0psi with a few tens of tons left to go?<A few tons of what? Are you referring to the force required to pull a piston? Force is not the same as psi.
>Wondering how much a vacuum 200' of water in a 1.25" pipe would equateto<a) Google says "You can lift water with a vacuum to a maximum theoretical height of about 34 feet at sea level" and "real vacuum pumps usually only lift water 20 to 25 feet"b) >Looks like it would be a vacuum of -106#<You're kinda mixing up measurements. Atmospheric pressure's 15psi is pounds per square inch. Getting a pounds-force number from that requires multiplying by a working surface area. So you cannot just subtract "15" from "106" - they're different measurements & units.c) If you pull a hard enough vacuum over water, the water would boil, then vapor will fill the vacuum & then no vacuum. Not sure if 200ft would do it, though.
I think it would be a very useful thing to grab a college physics text & study the chapter on hydraulics.
WayneWB4OGMOn Thursday, September 24, 2026 at 11:34:21 PM MDT, Facility 406 <facility_406 at bruteforcedevelopment.com> wrote:

Was looking at this...

https://reversopumps.com/gauge-vacuum-reverso/

-30in of mercury, so, I'm guessing -15psi, the opposite of what the 
gauge shows on the psi side.

Seeing as even at hobbyist levels I could pull a lot more inches of 
mercury, my smallest piston/actuator is something like 500#, and was 
looking at 28, 37, and 40 ton equipment this afternoon, what is it then, 
or do we just call it a hard vacuum at 0psi with a few tens of tons left 
to go?

Wondering how much a vacuum 200' of water in a 1.25" pipe would equate 
to, when sucked from the top, to within one foot of the surface.  Found 
a chart that says the water is 0.53# per foot.  Looks like it would be a 
vacuum of -106#.  Take 15 from that, of the atmosphere pushing down, and 
it's 91# pulling down on that 12" space.

I'm guessing there'd still be plenty of air in there, despite that, and 
it's something I can play with, using my well.

Maybe the problem is in the terminology, rather than how much something 
can pull on an actual space, and once the air in the space hits nothing, 
then we just have lifting, or implosion issues left, as we continue 
drawing toward infinity.

I did implode one cylinder years ago.  About 1" across, and I'd guess 
about 50# of pull, at which point is wasn't a vacuum so much, as the 
whole scenario just sucked, pun intended.

Kurt

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