My Tennis Ball Pressurizers

Injured Again

Hall of Fame
I don't understand the part when you say nrT is constant. If you are talking about the pressure and volume inside ball, nrT cannot be constant because when the pressure is higher outside the ball, air keeps going inside the ball nrT will keep increasing with the volume.

Will respond to this and all other messages when I get home - currently in Portugal.
 

happyandbob

Legend
I have a case of "Costco Penns" that I can't get repressurized. I bought them from someone for 50 cents a can because they didn't bounce and he didn't want them. I've had them in my Pressure Refresher for many, many weeks trying different pressures from 30 lbs to 50 lbs. I've only had 1 break under pressure. But none of them have repressurized at all. They all bounce like rocks. Any ideas on what to try?

Incidentally, I've always maintained that "Costco Penns" can't be different from anything else (how could they). But I've had dead Costco Penns like this before and I've never seen dead balls like this from anywhere else. I can't imagine why this could be the case.
30 to 50 is too high to start. i would try one week at 20 lbs and a second week at 24 lbs. 25 lbs is a threshold where the balls collapse and invert and then they never gain pressure
 

WilsonPlayer101

Professional
Right now I have one of my water filter pressurizers set at 34. I had put in two Penn Champion balls we just used once, you know opened the can and used them then I put a Wilson to make a three ball set. One of the Penns was hit over the fence into the brush and we couldn't find it, that is why I only have two pumping up plus one decent Wilson. My experience is sometimes two weeks in the pressurizer at about 34 is enough and some balls need three weeks. I may play Saturday which makes it two weeks.
 

happyandbob

Legend
Right now I have one of my water filter pressurizers set at 34. I had put in two Penn Champion balls we just used once, you know opened the can and used them then I put a Wilson to make a three ball set. One of the Penns was hit over the fence into the brush and we couldn't find it, that is why I only have two pumping up plus one decent Wilson. My experience is sometimes two weeks in the pressurizer at about 34 is enough and some balls need three weeks. I may play Saturday which makes it two weeks.
why would you need 2 weeks at 34 for a ball you've used once? You'll end up with a higher pressure ball than OEM out of the can.

3-4 days at 24 psi should be more than sufficient to get a once used ball back to 18 psi internal pressure.
 

Hulger

Semi-Pro
Those Penn balls are a joke. They have a completely different rubber than is used in any other ball, which makes them feel like heavy and hard cardboard, and that hollow sound :sick: they are even worse than Wilson Trinitys. Wouldn't be too surprised if they don’t accept air inside like other playable ones.
 

Hulger

Semi-Pro
why would you need 2 weeks at 34 for a ball you've used once? You'll end up with a higher pressure ball than OEM out of the can.

3-4 days at 24 psi should be more than sufficient to get a once used ball back to 18 psi internal pressure.
Come to think of it now,
what if the entire theory that the pores are closing when the balls are squeezed in high external pressure, is completely negligible? And what if there needs to be a high enough pressure gradient to push some air inside the ball?A practical example would be when you pump a ball or a tire through a valve; you notice that the pumping pressure must notably exceed the pressure inside before the air gets in. So there also might be a threshold value for those rubber pores.
 

Hulger

Semi-Pro
25 lbs is a threshold where the balls collapse and invert and then they never gain pressure
Might depend on the ball used and the starting pressure of the balls to be repressurized, but this is not case for Wilson balls and hence not to be generalized - Every one of our 60 balls sample survived from two week heat of 35 psi (+15psi)
 

happyandbob

Legend
Come to think of it now,
what if the entire theory that the pores are closing when the balls are squeezed in high external pressure, is completely negligible? And what if there needs to be a high enough pressure gradient to push some air inside the ball?A practical example would be when you pump a ball or a tire through a valve; you notice that the pumping pressure must notably exceed the pressure inside before the air gets in. So there also might be a threshold value for those rubber pores.
from practical experience, I put once used balls in a pressure can at 25 psi for 2 weeks. At the end of 2 weeks, they ended up too bouncy to use. Either that or my friend's kick serve started magically bouncing over my head.
 

happyandbob

Legend
Might depend on the ball used and the starting pressure of the balls to be repressurized, but this is not case for Wilson balls and hence not to be generalized - Every one of our 60 ball sample survived from two week heat of 35 psi (+15psi)
it depends how dead they are when you put them in. Fresh balls or once hit balls can survive higher than 25 psi. You cannot revive dead balls using more than 24 psi until the internal pressure of the balls gets close to factory.
 

WilsonPlayer101

Professional
why would you need 2 weeks at 34 for a ball you've used once? You'll end up with a higher pressure ball than OEM out of the can.

3-4 days at 24 psi should be more than sufficient to get a once used ball back to 18 psi internal pressure.
I don't know but I just thought the longer the more sure it will bounce well. I'll see how it goes.
 

Hulger

Semi-Pro
from practical experience, I put once used balls in a pressure can at 25 psi for 2 weeks. At the end of 2 weeks, they ended up too bouncy to use. Either that or my friend's kick serve started magically bouncing over my head.
Man, when did you last time play with fresh can of balls? :-D
 

WilsonPlayer101

Professional
Those Penn balls are a joke. They have a completely different rubber than is used in any other ball, which makes them feel like heavy and hard cardboard, and that hollow sound :sick: they are even worse than Wilson Trinitys. Wouldn't be too surprised if they don’t accept air inside like other playable ones.
I use them now and then and fresh out of the can they don't have such great bounce but they do accept air when pressurized. I noticed that they are good once pressurized. So I have good experience with them once pumped up in the pressurizer.
 

s40love

New User
Regular air doesn't work. I think you need a special kind of gas if you are doing the ball keg. I just pulled mine out of the keg after being in store for many years. If you keep putting regular air in it , the air will go to the top and compress the balls down to the bottom. The air will not get inside the balls. The ball will end up smushed, deformed. This is what a bunch of my balls in the bottom of the keg looked like.


All the balls were deader than they were when I put them in years ago when I was trying this experiment. It didn't work. I just happened to open the keg today.

This is my keg:
 
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ey039524

Hall of Fame
Regular air doesn't work. I think you need a special kind of gas if you are doing the ball keg. I just pulled mine out of the keg after being in store for many years. If you keep putting regular air in it , the air will go to the top and compress the balls down to the bottom. The air will not get inside the balls. The ball will end up smushed, deformed. This is what a bunch of my balls in the bottom of the keg looked like.


All the balls were deader than they were when I put them in years ago when I was trying this experiment. It didn't work. I just happened to open the keg today.

This is my keg:
How much pressure did you use?

I have mine sitting at 30 psi. Not seeing balls compress inward like this.
 

Ronaldo

Bionic Poster
Never kept my balls under pressure longer than 2-3 days. Whipped out my balls every time I practiced. And added new balls after play. Loved that sound releasing the seal/pressure
 

s40love

New User
Never kept my balls under pressure longer than 2-3 days. Whipped out my balls every time I practiced. And added new balls after play. Loved that sound releasing the seal/pressure
How much pressure did you use?

I have mine sitting at 30 psi. Not seeing balls compress inward like this.
I don't remember. It's been a long time. I remember pressurizing it multiple times to see if it helped but it never did. So I think it's a myth. You need to leave it for a long time and put more pressure in to see balls looking like this.

Try using some dead grand prix . They are softer.
 
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Injured Again

Hall of Fame
Regular air doesn't work. I think you need a special kind of gas if you are doing the ball keg. I just pulled mine out of the keg after being in store for many years. If you keep putting regular air in it , the air will go to the top and compress the balls down to the bottom. The air will not get inside the balls. The ball will end up smushed, deformed. This is what a bunch of my balls in the bottom of the keg looked like.


All the balls were deader than they were when I put them in years ago when I was trying this experiment. It didn't work. I just happened to open the keg today.

This is my keg:

That looks like you put too much pressure in, causing the ball to collapse, and then you left it that way for so long that the rubber took a set in its deformed state. Typically the carcass of a good quality ball can resist about 15-20 PSI more than its internal air pressure before collapsing.

Air pressure works equally on all sides of the ball, not just from the top. However, balls are not entirely uniform and will collapse from too much external air pressure at the weakest point in the carcass.

For US Open balls, I'll open two cans, play with them for 90 minutes, and throw them in the pressurizer with 25-28 PSI. After play, they lose maybe an inch or so of bounce but that gets restored after a couple of days in the pressurizer. The second time playing with them degrades them more, probably from the rubber being work-hardened, and even if I then re-pressurize the balls a second time, it takes several days to restore the bounce height but they still lose forward speed after the bounce, making it a good proxy for what play on a slower court would be like.
 

ey039524

Hall of Fame
I don't remember. It's been a long time. I remember pressurizing it multiple times to see if it helped but it never did. So I think it's a myth. You need to leave it for a long time and put more pressure in to see balls looking like this.

Try using some dead grand prix . They are softer.
I actually use grand prix. According to TW's tests, they're the softest, besides trinitis. They also are much more lively than most other balls.
 

happyandbob

Legend
Regular air doesn't work. I think you need a special kind of gas if you are doing the ball keg. I just pulled mine out of the keg after being in store for many years. If you keep putting regular air in it , the air will go to the top and compress the balls down to the bottom. The air will not get inside the balls. The ball will end up smushed, deformed. This is what a bunch of my balls in the bottom of the keg looked like.


All the balls were deader than they were when I put them in years ago when I was trying this experiment. It didn't work. I just happened to open the keg today.

This is my keg:
You collapsed the balls and left them under pressure like that for years, of course they are deformed. It has nothing to do with the type of gas you are using and everything to do with the pressure

Pressurize dead balls starting at 20 lbs and leave them there for a few weeks before you try to increase the pressure. Listen carefully as pump up the pressure, you can hear a sound when the balls invert because they can't handle the pressure. If you hear the sound, you'll need to release the pressure and try pressurizing again.
 

onehandbh

G.O.A.T.
The ideal would be a ball filled with 70% sulfur hexafluoride 30% air, but this won't happen soon for a variety of reasons:


A very simple way to pressurize balls is to:

1. Take a premade ball saver
2. Drill a hole and insert a schrader valve
3. Use a hand pump with a pressure gauge to pump it up

This is also convenient because you can use the cap of the schrader valve to release the pressure and it's easy to open the can safely. Minimal equipment and space needed - I keep it all in my bag. FYI, apparently my tennis ball saver was only doing ~8psi, not the advertised 14psi... now I pump it up to 20psi right after a session and it only drops 1psi every few days (I don't know what the can is rated for, especially with a hole drilled into it, so I'm uncomfortable going beyond 20psi).

Have you tried pumping it beyond 20psi? 25? 30? Was there a particular schrader valve you bought that works well with the pressurizer tube you use?

Anyone else try drilling one a small hole into one of the existing screw-type ball pressurizers and installing a valve for pumping air into it?
 

onehandbh

G.O.A.T.

I still use the modified Gexco savers, but have largely switched to these: https://www.amazon.com/BALL-RESCUER-Containers-Pressurizer-pressurize/dp/B074PQLTXW

They work great and are way lighter to carry around
How do you add pressure to this water filter container?

Doesn't it have two holes on the lid?
 

Injured Again

Hall of Fame
Have you tried pumping it beyond 20psi? 25? 30? Was there a particular schrader valve you bought that works well with the pressurizer tube you use?

Anyone else try drilling one a small hole into one of the existing screw-type ball pressurizers and installing a valve for pumping air into it?

I would seriously, seriously, SERIOUSLY recommend against doing that. The screw on lid pressurizers are plastic and will behave like PVC pipe under high pressure. PVC pipe gets brittle with age, nicks to the surface can cause weak spots, and will explosively come apart. I believe there are regulations against using PVC or other plastic pipes for air pressure for that reason.

Here's a video that is closely enough related.

 

happyandbob

Legend
How do you add pressure to this water filter container?

Doesn't it have two holes on the lid?
I don't mess around with home brew ball savers anymore. Adding a bike pump valve on the screw-type ball savers allowed me to add pressure but they weren't maintenance free.

I only use these now: https://www.amazon.com/gp/product/B074PQLTXW

So easy, but they only work on Penn Champ cans. No other cans work, not even ProPenn cans work.
 

Injured Again

Hall of Fame
I don't mess around with home brew ball savers anymore. Adding a bike pump valve on the screw-type ball savers allowed me to add pressure but they weren't maintenance free.

I only use these now: https://www.amazon.com/gp/product/B074PQLTXW

So easy, but they only work on Penn Champ cans. No other cans work, not even ProPenn cans work.

I would expect a tennis ball can to tear open rather than explode in a shower of shrapnel like a rigid plastic vessel. How much pressure have you tried and how long does one can last before you have to use a new ball can?
 
I don't mess around with home brew ball savers anymore. Adding a bike pump valve on the screw-type ball savers allowed me to add pressure but they weren't maintenance free.

I only use these now: https://www.amazon.com/gp/product/B074PQLTXW

So easy, but they only work on Penn Champ cans. No other cans work, not even ProPenn cans work.
$36 seems pricey when you have to supply the container, and the thing is fussy about which one. We use US Open extra duty—we’re not likely to switch. We also usually use six balls bc we’re lazy about picking up balls during play. One of us has the 5 gallon brew keg and an air compressor. They sewed a long cloth pocket to hold the balls before putting them in, making it easy to pull out more than one at a time just by grabbing the top.
More than one way to skin this one.
 

Ronaldo

Bionic Poster
$36 seems pricey when you have to supply the container, and the thing is fussy about which one. We use US Open extra duty—we’re not likely to switch. We also usually use six balls bc we’re lazy about picking up balls during play. One of us has the 5 gallon brew keg and an air compressor. They sewed a long cloth pocket to hold the balls before putting them in, making it easy to pull out more than one at a time just by grabbing the top.
More than one way to skin this one.
Great idea on the cheesycloth bag. Took forever to shake the balls out of that corny keg.
 

SunkTheBirdie

New User
Looks like I can't post pics. I thought I could just upload from my computer but it looks like they have to be hosted to a site first then the link posted here to load a picture. You used to be able to just upload from a file on the computer. Too much trouble hosting to a website then do the link.
Agreed.

It is practically free to host files so TW shouldn’t be concerned about cost.

I’ve never seen a xenforo site other than TW disallow uploading image files.

Weird take.

It essentially kills the instruction / learning forum.

It goes without saying, google loves unique images. So enabling users to upload images, in this case DIY ball pressurizers is good for the health of the forum as a whole.
 
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