Let me just say that, YES, it is a good idea to Recharge flat balls with FELT in good shape.
Just because it is a flat ball doesn't = no felt.
I don't know why everyone assumes this.
Heck, you can open a new set of balls that haven't even been used
, and a couple days later they will be pretty much useless for serious playing. ONLY because of the lost pressure.
The PVC pipe sounds great but...
1. Have you tried to build one yourself?
2. Have you personally used a PVC pump that WORKS? (Every one I have seen has some sort of design flaw. I Personally have never seen one the works as good as the pressureball)
3. How many other people are going to take the time to construct such a device (that works) and spend more on making it than getting a tried-and-true device?
4. You will look like a fool bringing a huge PVC pipe out into the tennis court! lol
Even though the website says 8 balls, I can actually squeeze 9 balls into the Pressureball...Plenty for a match. And it is super easy to use. It's Inexpensive. It WORKS. And doesn't look like a red-neck potato gun.