4 December 2019

Can you repressurise tennis balls? It's a long story...

When we wrote about making tennis greener last week we were asked why we hadn't mentioned repressurising old balls. Meanwhile last week's "Meet the Player" interviewee made an interesting discovery. Now we have a tennis-ball tale to tell...

"Why didn’t you mention Pressureball?" asked Jamie, one of our Edinburgh players, in response to our greener tennis article last week. "I get 10 times more use out of my tennis balls from it. Check it out online."

New balls for old

PressureBall works by putting balls back under pressure. The aim is to prolong the life of new balls and also revive old balls. So not only do you save money on balls, you save on packaging and don't put more plastic back into the system. PressureBall (37 euros for tube & pump) is not the only repressuriser on the market but it appears to have an excellent track record of success. But could you build your own repressuriser? Tennis balls should have an internal pressure of 14psi and constructing a reviving chamber should be achievable says Tommi on Only Some Projects a website dedicated to "random projects". All you need is a pressure cooker and some bits and bobs. But the method comes with a pretty severe warning: "What I am going to present in the following involves handling large amounts of compressed air. That is potentially very dangerous and I do not guarantee that anything that I present is actually safe to do so."

And that wasn't the only feedback from last week. "Look what I have found in the back of one of my parents' cupboards," Emily, our Meet the Player interviewee WhatsApped, accompanied with pictures of some amazing vintage tennis balls.

Pressureball, it turns out, is a clever gadget for repressurising tennis balls that those in the know have been using for some years (see box), and Emily's discovery helps shed light on the long journey that tennis balls have made since the origins of the sport.

At the dawn of tennis time, tennis balls were straw-stuffed, leather-clad and lighter cousins of cricket balls. But with the invention of vulcanised rubber and know how by Charles Goodyear, they have been cloth covered rubber spheres. Originally, as reported on the website of Price of Bath (the UK's last remaining tennis ball manufacturer) these rubber-based balls weren't pressurised: There was "no added internal pressure so there is no pressure to lose. All the bounce and ‘compression’ is produced by the rubber compound." Indeed, that is the way Price of Bath believe, in an ideal world, it still should be:

"Tennis balls were pressurised because the rubber compound used was not of the best and they were either too hard or soft, or low in bounce without added internal pressure, and [the process] conveniently allowed the use of cheaper ingredients. Of course tennis balls have been going soft quickly every since, having a relatively short life and affecting the game."

The battle to return to original hollow, unpressurised ball is, even Price of Bath admit, lost and certainly by 1947, the date on one box of Emily's Slazenger balls, tennis balls were  pressureised. But how did they retain their bounce when they were simply packaged in a cardboard box? 

The solution was to over-pressurise the balls which meant that balls at the start of the season were likely to be livelier than those at the end. Curiously, they were also slightly larger than the standard size, shrinking on to the regulation diameter as the season went on. By December, balls were close to their sell by date and would be discounted. Players had to get used to the way that even new tennis balls would not necessarily be consistently the same and bouncing balls to find the best one before a match (or even each serve) was one of the rituals of tennis.

Tennis balls in cans began to make an appearance in America as early as 1926 and for many years were opened, like cans of sardines, with a key. Many balls, however continued to be sold in boxes, and if they were good enough for the LTA and Wimbledon well into the 1960s, then they were good enough for the rest of us.

Emily may well be grateful that she looked in her parents' cupboard (some of the tennis balls she found she believes belonged to her grandparents)... Old tennis balls and their packaging has become collectable and Tennis Collectors of America (see pic left) is dedicated to the hobby. 

"The Slazenger box is collectable," says Michael Eden a founder and current Board member of the Tennis Collectors of America, "but they are fairly common and worth around $25-50 dollars depending upon condition." Michael is also President-Elect of the United States Tennis Association-Kentucky and it looks as if we have a new friend across the pond "I enjoyed learning about your successful league program on your website. We share a similar goal with our leagues and programming to get more people playing tennis."

If we are ever in Kentucky, we promise to look Michael up, but to avoid any confusion to him (or anyone else) the clip below represents tennis in Britain at the time of Emily's 1947 box of tennis balls. Things have changed just a little! 

Centred on Wimbledon 1947

Wimbledon 1947: This fascinating BFI documentary features the same Salazenger tennis balls that Emily uncovered. Follow the link to watch for free.

Get playing whatever balls you use by finding a league near you here!