Losing vacuum pressure gradually. Is this normal?

I am using an air vacuum pump with a gauge. Is it normal to lose vacuum pressure gradually over time? For example, if the pressure is 10”hg, and after a couple of minutes, it gradually goes down to 9”hg. Is that how it supposed to be? If so, why does it lose vacuum? I thought once you set it to a certain pressure e.g. 10”hg, it would stay that way for 30 minutes or so? So is this normal or is my air pump faulty? Please help with this, I am so damn confused!

Losing 1”hg in 30 seconds would be a pretty big leak, but what you describe is normal. Small leaks can occur at the base, or in the male connector O-ring seal, or even small leaks past the piston in your hand pump. One squeeze of the pump handle every couple of minutes isn’t really that burdensome is it? If you just can’t stand it, look into an electric pump, but those can get expensive.

To make the male connector leak proof, I wrap the thread in plumbers teflon tape in addition to the O-ring. For leaks at the base, shaving helps.

An unscientific explanation: When you create a vacuum in the cylinder, you are reducing the amount of air in the cylinder. In turn the vacuum causes your dick to “swell”. As your dick swells. It replaces some of the space previously occupied by the air which, in turn, reduces the vacuum in the cylinder. Accordingly, you will need to pull out more air to compensate for the increased space taken up by the swollen dick.

This will continue on a decreasing rate until you no longer need to pump out air to maintain the vacuum level.

I just test my system to see how much pressure I am losing. I removed the hose from the pump, and put my thumb over it for a few minutes, no pressure was lost. I then put the hose back on the pump, and put my thumb over the end of the hose for a minute, and it was gradually losing pressure. I’m surprised because I can’t see how it’s losing pressure from the hose. Both ends are tightened very securely, and can’t be tightened any further. How can you lose pressure from the hose? Do you have any explanation for this?

Anyone know why?

Are you missing a good silicon sleeve?

Pumps don’t have silicone sleeves?

You can buy a separate sleeve for a tight suction but it can be dangerous.

Losing vacuum gradually might be good to prevent excess force and injuries.

That was not my question though.

So no one knows the answer to this problem?

Read Gprents reply again.

Can you elaborate?

Inside your hand pump there is a piston that has an O-ring seal. With a lot of use, the O-ring gradually loses its ability to seal 100% and allows vacuum to escape. So, if your pump is still new, that is an unlikely source for a leak, but something to remember for the future.

I have never had a hand pump system that did not steadily lose pressure. Not one. I went electric because hand ones seem to lose vacuum no matter what.

I’ve tried at least a dozen hand pumping systems. None are actually perfectly sealed. Electric aren’t either but they make continous micro adjustments to maintain the pressures you set. So if you set 10HG, it ranges pretty close to 10HG. Period.

I have used a Harbor Freight brake bleeder pump for over six years using five different cylinders and have not experienced a leak, yet.