How to estimate your personal maximum sucking vacuum in HG

My cylinder is 1 11/16" diameter so has an area of 2.23 square inches (radiusxradiusx3.14). I smeared a thin layer of vaseline on the lid of a jar of pickles which weighed 5.5lb (including the jar weight). I then sucked on the tube with the cylinder on the jar lid and I was able to lift it after only a bit of sucking vacuum. 1 inch Hg=0.49pounds per square inch. I was sucking at a vacuum of 2.47psi (5.5/2.23) which is equivalent to 5" Hg (2.47/0.49). I will have to find a larger weight to find out the max I can lift but I think I could lift 10lb. Somebody claimed to be able to suck to 27Hg. Say this was with a 2" tube. So to calculate the weight W as above

27=(W/{1x1x3.14})/0.49
27=W/(0.49x1x1x3.14)
W=0.49x1x1x3.14x27=41.54lb

just as mine was 5.5(lb)=0.49(psi)x0.843(R)x0.843(R)x3.14(pi)x5(Hg)

Being able to lift 41.54lb sounds a lot to me so maybe his quage was in cm Hg rather than inches Hg which means it is out by a factor of 2.54 meaning he lifted 16.35lb which sounds more reasonable. For larger weights I plan on trying a large soda bottle maybe full of stones, the rounded smooth tapered neck should fit most cylinders. If trying to lift weight make sure the weight’s centre of gravity is in line with the middle of the cylinder.

Here is some similar number crunching
Equating pumping and hanging?

Since you’re working with a vacuum and not pressure are you remembering that at sea level the weight of the air above you (measured as one “atmosphere”) must be considered and that it is contributing 14.7 psi to your equations?

Regardless of what you determine, using one’s mouth to provide vacuum for PE can easily result in injury because the amount you can produce is way more than the 4-6 inches Hg that most sensible pumpers use.

I thought it was all guage pressure. Atmospheric pressure is 30.7”Hg is this taken into account in valve readings?

I thought you weren’t using a system with a gauge. When there is one present, and the system is open and the gauge is at zero, then the atmospheric pressure is neutralized. When the system is closed and a vacuum is created in the cylinder, then the gauge gives a reading that is sub-atmospheric because one side of the gauge mechanism “sees” the cylinder and the other “sees” the room around you or the atmospheric pressure around you. The needle moves because the pressure in the cylinder is now less than the atmosphere. So, yes, atmospheric pressure is taken into account when the needle is zero.

My point was that in opposition to the weight of the object being lifted, you have the pressure of the atmosphere around it to consider. Since the inside of the cylinder is sub-atmospheric, part of what is holding the jar lid to the cylinder opening is the pressure of the atmosphere against the jar. Since you were working with pounds per square inch (psi) I gave the pressure of one atmosphere (at sea level) as equaling 14.7 psi. You have to subtract that from the weight of the jar (in psi) to know what the vacuum is really holding.

(I guess. I’m not a physicist.)