Pressurized Ball Savers

Following this post (link), I recalled my previous attempt to build and test the efficacy of a pressurized ball saver. 

(Thanks to M, who sponsored most of the materials earlier)

I had wanted to test it out on several different brands of balls together, but the stores was left with only one. While waiting for stocks to replenish, this completely slipped my mind.

So now, this is picking up steam again...

Objective:
- To test if used tennis balls with a diminished bounce could be restored to regulation play (link).

Methodology:
- Three different brands of pressurized balls were used.
- Two cans were bought per brand. Total 18 balls.
- Within each brand, 2 balls were set aside unused outside its container to let it deflate. The other 4 balls were used for matchplay. 
- All balls were marked for easy identification later.
- Bounce height from a 100" drop was measured for all balls when new and used.

Here's how my DIY pressurized PVC tube looks like. If you're planning to build one, there's plenty of instructions available online.

This tube could hold about 15 balls. I filled it with:
- 6 used balls from 3 different brands,
- 6 unused but deflated balls from 3 different brands,
- 2 pressureless balls, 1 used, 1 new.

Then it was connected to an air compressor set to 20psi. The auto-regulated air compressor eliminates the need to check and re-pump air regularly. It also ensures the balls are subjected to a constant air pressure throughout.

The balls were left in there for a week, then taken out to test its bounce before being put under pressure again. This cycle was repeated for four weeks.

Results:
- For both pressureless balls, there was no difference at all in their bounce at any point in time.
- Among the 6 used balls, a slightly higher bounce was observed in 2 balls in the drop test. When played on the tennis court, they still felt a little flat compared to those fresh from the can. There was no change in the other 4 used balls.
- All 6 unused but deflated balls registered a higher bounce than before, although to different degrees. The air pressure held well during play but still, they could not pass off as new.

Please note this was never intended to be an exhaustive nor conclusive test of pressurized ball savers, or tennis balls. It's more to satisfy my personal curiosity.