Tennis Ball Pressurizer test (before & after)

[onehandbh]

A few years ago I bought the ZT-1 CAP Tennis Ball Pressurizer.
It is basically a 2 piece lid that clamps onto the top of a tennis ball can and has a valve for inflating.

Finally giving it a test. I tried pumping it to various pressures and found that at around 22-23 psi, the balls collapse.
So for my test I pumped it up to 20 psi today.

I will leave the balls in the pressurizer for about a 5-7 days. I recorded slow motion videos of the balls bouncing before being inserted into the pressurizer.

I will also check on the internal pressure after a day to see if it went down. Stay tuned for the video of the final results.

Here is what it looks like:

 

[Purestriker]

A few years ago I bought the ZT-1 CAP Tennis Ball Pressurizer.
It is basically a 2 piece lid that clamps onto the top of a tennis ball can and has a valve for inflating.

Finally giving it a test. I tried pumping it to various pressures and found that at around 22-23 psi, the balls collapse.
So for my test I pumped it up to 20 psi today.

I will leave the balls in the pressurizer for about a 5-7 days. I recorded slow motion videos of the balls bouncing before being inserted into the pressurizer.

I will also check on the internal pressure after a day to see if it went down. Stay tuned for the video of the final results.

Here is what it looks like:

Is this for science? Or do you intend to use them again?

 

[Westerwick]

Is this for science? Or do you intend to use them again?

I believe it must be only for science since there is no source or mention of this device on any auction, sales or search site. Even if it is a raging success, nobody can get one to duplicate the results.

 

[onehandbh]

Is this for science? Or do you intend to use them again?

I bought it a few years ago, but now it looks like it is no longer sold.

Got busy so am a bit late with testing again.
Amazingly, the can has remained pressurized this whole time.

The true test will be whether the balls improve in bounce. I will also do another test after playing with them to see how much of the pressure is retained.

 

[Dags]

I believe it must be only for science since there is no source or mention of this device on any auction, sales or search site. Even if it is a raging success, nobody can get one to duplicate the results.

They were branded as Zombie Tube. I got the impression it was one guy in his garage. The photo in this thread shows the first iteration; he made an amendment to the design so that you could remove the cap without completely unscrewing the wing nuts.

I have four of these, and believe the optimal way to use them is to rotate balls and let them repressurise for a week+ between hits. They do work to restore pressure to dead balls over a longer period, but my experience was that they play better if you can prevent some of the loss in the first place. I had open balls that have sat for very long periods of time during the various lockdowns of the past two years, and have been fine to play. Never quite 'as new', but good enough to get some extra sessions.

However, the critical thing is what surface you play on. When I play on carpet, balls can be used for a few sessions. On acrylic, they're shot after one, two at a push. The felt just wears too fast.

I will also note that where I live balls come in cans of four and I only buy premium offerings. Three cheap balls may give very different results.

 

[onehandbh]

Here are the results!
I originally intended to open the can after 1 week but I got a little busy. What was surprising was that the ZT-1 did not seem to lose any pressure from Nov 23 to Dec 13.

For the test, I used my fingers to gently push the balls off the kitchen counter top.

 

[kevin qmto]

Where can you even find one of these?

 

[Injured Again]

@onehandbh I like the test. In my experience over the past year, it seems it takes roughly one week to re-pressurize once-used balls back to as-new bounce heights, if they are pressurized up to 30 PSI and it is done within an hour or so after coming off court.

There are a couple of things with that though. First, the used balls are a bit fluffier, and the rubber core seems to get more energetically lossy as the ball is used, so the internal pressure has to be increased to over an as-new ball's pressure in order to have the same bounce.

Balls are super hard to get a hold of - many types are out of stock even at Tennis Warehouse. And prices have gone up a fair amount over just the past month or two.

 

[Sardines]

I made a repressurizer out of 2 beer kegs following instructions from youtube. They are great for reusing balls used in match play for practice. My kids go through ¼ of the balls after I set this up. The keg solution isn't elegant, but can fit 30ish balls in each keg and they have to be individually put in and taken out. Tennis is already so wasteful so extending the use of balls is a nice way to lower the impact to the environment by extending the use of the equipment we use.