How To Pressurize / Revive Old Tennis Balls...

bfroxen

Rookie
I use a 3-gallon, wide-mouth garden sprayer by Chapin. They're available many places online. I cut the pump out and sealed up the resulting opening with a PVC cap and silicone. I installed a presta valve in the hose (cut short) with a hose clamp to secure it, and I use a bicycle pump with gauge to pressurize it. It holds 49-50 balls. The balls won't flow out the opening, but I can reach my largish hands inside and pull out two balls at a time.
 

SFrazeur

Legend
Just get a Corny keg (ball lock style). They run around $60 shipped online and with a like ~$15 of parts you get a pressurizer that holds 55 balls easily and is strong and safe to use. Parts include tire valve stem and lock connector and hose.

Kegs have a working pressure of approx 130PSI. I pressurize at 50PSI. Well under its limit.


Myself, I have been CO2 to re-pressurize as ReBounces does; which requires a CO2 tank and regulator. This increases initial costs.
 
I've been tinkering with the idea of building this for some months, but only now started to put on the work of searching and building something. I actually work at a pressure tank factory just like the one obana48 posted. We have tanks of various capacities.

Obviously the membrane isn't required for this, but it's a good idea to cut the throat of an old/ruptured one to work as a seal. Or if you find a damaged/leaking tank with the membrane still intact it still works, just put the balls inside the membrane, then screw a flat cap accessory on the flange tube and drill a hole in it for a valve. The problem is the inconvenience of screwing/unscrewing the flange screws, and it's even worse if you want to move it constantly. Because of this i'm still searching for an plastic container to test, but i'm still a bit afraid of the pressure dangers. What kind/wall thickness of plastic would be strong enough to withstand this kind of pressure?

Since I have access to tools, parts and know how in the factory i'll try to engineer some way to seal the tank more easily, so suggestions are appreciated. I also want to build a small tube gizmo for 3 or 4 balls
 
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v-verb

Hall of Fame
I went down the pressurizing rabbit hole. Bought the corny keg and everything. gave up on making it work and took the thing to the dump. Just got a bag of 60 Gamma or Tourna balls (yes the ratings on Amazon were crappy) but guess what? They worked wonderfully in the ball machine and are just fine for practice.

MUCH better than the old dead balls the local coaches use
 

v-verb

Hall of Fame
I couldn't get a proper seal. It's possible I got a bad one but I'd had enough.

Glad yours is working though
 

wangs78

Hall of Fame
Honestly, just get one or two of the Gexco Ball Saver cannisters that sell for about $15 online and use them to keep balls fresh for practice or pickup sets. For league or other serious matches, use new balls. I've gone down this path of trying to keep large numbers of balls fresh and it really is not worth the trouble. The investment of time and money into ball saving equipment is better spent doing other things.
 

v-verb

Hall of Fame
Honestly, just get one or two of the Gexco Ball Saver cannisters that sell for about $15 online and use them to keep balls fresh for practice or pickup sets. For league or other serious matches, use new balls. I've gone down this path of trying to keep large numbers of balls fresh and it really is not worth the trouble. The investment of time and money into ball saving equipment is better spent doing other things.
Yep my experience exactly. But for those who have succeeded kudos to them
 

identitee

New User
Honestly, just get one or two of the Gexco Ball Saver cannisters that sell for about $15 online and use them to keep balls fresh for practice or pickup sets. For league or other serious matches, use new balls. I've gone down this path of trying to keep large numbers of balls fresh and it really is not worth the trouble. The investment of time and money into ball saving equipment is better spent doing other things.
I think most people who are trying to keep large amounts of balls fresh are using them for ball machines or coaching. I agree that for practice sets etc., it's not worth it, and you're better off using new balls.
 
I think most people who are trying to keep large amounts of balls fresh are using them for ball machines or coaching. I agree that for practice sets etc., it's not worth it, and you're better off using new balls.
This.

I keep about 150 balls for my machine and prefer them to be pressurized for more realistic performance.
 

LGQ7

Hall of Fame
just add dot com.

But does it really work?
Yes. BUT it takes 3 months to re-pressurize dead balls. For new balls, it keeps the pressure like new. I recommend you buy 3. 1 for using, 1 for "charging", 1 for "charged".
 

obana48

Rookie
Has anybody had experience with Babolat Roland Garros balls?

I'm asking because I haven't had any luck with Head ATP balls. These balls cannot be re-pressurized (though I haven't tried pressure above 25psi yet. May be going to 30 or 35 will help...).
 

esantoro

Rookie
Has anybody had experience with Babolat Roland Garros balls?

I'm asking because I haven't had any luck with Head ATP balls. These balls cannot be re-pressurized (though I haven't tried pressure above 25psi yet. May be going to 30 or 35 will help...).
Why can't certain pressurized balls be re-pressurized?
 

esantoro

Rookie
At least for a PVC pressurized tube, this looks easy enough:

I have now built two of these tubes. However, they are not air tight and lose pressure over a number of hours. I used two-part epoxy to glue all the fittings. I don't think the epoxy is a good choice for air-tight fittings. I also used hot glue to seal the valve, top and bottom, which also doesn't seem like a good choice.

Any suggestions for the following:

1. A good glue to create air-tight fittings
2. A good sealant to make the valve seat air-tight


I still need to determine where the greatest air leak is, it may be with the threads to the screw-cap, even though there is a rubber seal in the cap.
 

esantoro

Rookie
Has anybody had experience with Babolat Roland Garros balls?

I'm asking because I haven't had any luck with Head ATP balls. These balls cannot be re-pressurized (though I haven't tried pressure above 25psi yet. May be going to 30 or 35 will help...).
Which balls cannot be repressurized: Babolat Roland Garros or Head ATP?
 

obana48

Rookie
I repressurise Penn ATP balls all the time. If those balls are the same it will work with C02 in a keg at 50PSI.
Thank you, SFrazeur. That's very interesting. Unfortunately I won't be able to use CO2. Only air. But next time I'll try higher pressure.
 

Ken41

New User
Trying the Corny Keg. I have some questions I haven't found answers for (did some searching here and elsewhere; none or varying answers).

When pressurizing, as has been mentioned by others, some balls are collapsing around 20+ lbs.

Question 1: Will those collapsed balls eventually come up to pressure and pop back to normal shape? Or are the collapsed balls lost for that pressurizing session?
Just wondering whether you really need to start at a few days at lower pressure (around 20 psi) for the really flat ones to catch up...Or can you just go straight to 30? I saw that SFrazeur does 50 psi so I would guess most balls are collapsing during pressurization.

Question 2: What is the ideal pressure?
I saw somewhere that balls are made at 14 psi. So 14 plus atmospheric 14.7 would be 28.7. So it makes sense a lot of folks go for around 30 psi. But is that correct? Again, SFrazeur is doing 50.

Question 3: How long for pressurization?
I saw someone here said 3 months for regular air? Others say a week or two. The Green Machine is 3 days with their "gas blend" which someone here said is CO2.

Question 4: Temperature?
I saw someone mentioned warming allows for faster pressurization. I assume higher temp would also raise pressure. So I guess going at higher temp and pressure; once balls cool, it could go back to "ideal" pressure. Anyone find ballpark numbers yet?

Sorry. Just don't want to waste time if someone else already experimented and found a decent method.
 

GeoffHYL

Professional
Re Q2, I believe pressure is measured relative to atmospheric, so when balls are pressurized at 14, that is above atmospheric already, so no need to at 14.7. I have used the Pressureball at about 25 PSI for long periods, and the balls are definitely bouncier than new.
 
Collapsed balls will probably take years to pressurize because the pressure will drop as it returns to round.

I usually do 20lbs for a month. They pressurize at different rates and it gets me decent results for the ball machine.
 

Ken41

New User
Thanks for the replies!, SFrazeur, GeoffHYL, and Maximus XXIVI!

As I said earlier, I can hear some balls collapsing when pressurizing, at around 20 psi. Here's a vid I found with the tell-tale sound:

My first attempt/experiment will be one week at 30 psi. I have - unscientifically - marked what I felt was the softest (flattest) and hardest balls. Before and after, I will do a 100 inch drop and measure the average bounce height of each (I believe official rules say ball should bounce 53-57 inches). My hypothesis/guess: I think pressurizing at 30 psi will collapse the softest balls and they will not improve in pressure/bounce height at all. But the hardest/highest psi balls should improve some (prayer emoji).

Another possible factor: I read that temperature may play a role with gas permeability of the rubber. I live in Hawaii and do not have air conditioning. So when we're out at work during the day and the house is closed up, the interior temp is probably around 90 degrees F; higher in summer. About 10-15 degrees cooler at nite.

We'll see...
 

Ronaldo

Bionic Poster
Thanks for the replies!, SFrazeur, GeoffHYL, and Maximus XXIVI!

As I said earlier, I can hear some balls collapsing when pressurizing, at around 20 psi. Here's a vid I found with the tell-tale sound:

My first attempt/experiment will be one week at 30 psi. I have - unscientifically - marked what I felt was the softest (flattest) and hardest balls. Before and after, I will do a 100 inch drop and measure the average bounce height of each (I believe official rules say ball should bounce 53-57 inches). My hypothesis/guess: I think pressurizing at 30 psi will collapse the softest balls and they will not improve in pressure/bounce height at all. But the hardest/highest psi balls should improve some (prayer emoji).

Another possible factor: I read that temperature may play a role with gas permeability of the rubber. I live in Hawaii and do not have air conditioning. So when we're out at work during the day and the house is closed up, the interior temp is probably around 90 degrees F; higher in summer. About 10-15 degrees cooler at nite.

We'll see...
Curious, where are all the window screens in Hawaii? Including restaurants. Birds fly in, picking up food, crumbs, whatever.
 
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