travlerajm
Talk Tennis Guru
when I do the iterative venting, the chamber gets cold.I would assume the temperature change negligible though.
when I do the iterative venting, the chamber gets cold.I would assume the temperature change negligible though.
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.
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 pressureI 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.
Same principle as when I try to ramp up my tennis activity after a layoff. If I start too intense, my legs lose structural integrity.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
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.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.
Come to think of it now,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.
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)25 lbs is a threshold where the balls collapse and invert and then they never gain pressure
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.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.
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.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)
I don't know but I just thought the longer the more sure it will bounce well. I'll see how it goes.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.
Man, when did you last time play with fresh can of balls?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.
Only for matchesMan, when did you last time play with fresh can of balls?![]()
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.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 soundthey are even worse than Wilson Trinitys. Wouldn't be too surprised if they don’t accept air inside like other playable ones.
How much pressure did you use?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.
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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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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
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.How much pressure did you use?
I have mine sitting at 30 psi. Not seeing balls compress inward like this.
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
You might think it does but it's your imagination. This does not work. Just trying to save others time and money.
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.
![]()
New item by 40 luv
photos.app.goo.gl
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:
![]()
New item by 40 luv
photos.app.goo.gl
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.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.
Nuke your balls before playing, tennis balls. Just not too long, may popI 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.
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 pressureRegular 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.
![]()
New item by 40 luv
photos.app.goo.gl
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:
![]()
New item by 40 luv
photos.app.goo.gl
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?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).
How do you add pressure to this water filter container?Upgrading a Tennis Ball Saver
I have a big box of dead tennis balls that I've been collecting to eventually ship out to https://www.recycleballs.org. I was looking at the balls the other day as I was dropping a new set in, and many of the balls are dead but the felt seems to be in decent shape. I have a couple of the...tt.tennis-warehouse.com
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
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 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.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.
$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.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.
Great idea on the cheesycloth bag. Took forever to shake the balls out of that corny keg.$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.
Agreed.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.