Gear Talk: Bill Dirst, reBounces

by: Justin diFeliciantonio | October 25, 2012

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Recently, I spoke with Bill Dirst, Chief Executive of reBounces and inventor of the Green Tennis Machine—an apparatus that uses inert and non-flammable gases to restore the bounce height of used tennis balls. The company retails three machines—the GTM 150, 250, and 400, all named according to their ball capacity. (GTMs range from about $2700 to $4800, not including a service contract, and can recharge balls in three days, according to reBounces.) Dirst, among other topics, talked about the genesis of his idea, how he carried it through to fruition, and the future of his company.


Justin diFeliciantonio: I’ve read in other articles that you originally were a high-school English teacher. How did you go from teaching to starting a company that restores tennis balls?

Bill Dirst: It’s definitely been an interesting mix. I studied English at Clemson, and much later got an M.B.A. from the University of Arkansas at Little Rock. But most of my career’s been in education. I taught middle-school and high-school English, and CISCO-network engineering in north Arkansas, not too far from where our headquarters are located, here in Harrison. I also worked on geographic information systems for the Arkansas Dept. of Ed. I’m kind of a, what is it, jack-of-all-trades, master of none. And that’s what got me into this.

JD: I imagine you’re a tennis player as well?  

BD: Yeah, I’ve been a tennis fan and a recreational player all my life. I love tennis. My dad loved tennis. My brothers and sisters played tennis. I’ve played [USTA] League Tennis and tournaments. But it wasn’t until I was a high-school coach in the late ’90 that I really came to see the impact, the financial and environmental costs, of tennis balls. If you’re just buying a can of three, it’s not that big of a deal. But when you’re filling hoppers or baskets, it’s pricy. And it always seemed a shame, tossing balls away that still looked very good but didn’t bounce well. It was really then, when I was coaching, that I realized there just had to be a better solution.

JD: There have been several contraptions released over the years that claim to prolong ball life—the Tennis Ball Saver, for example. But there’s never been anything for large-scale ball reviving, like your Green Tennis Machines. How did you arrive at that solution?

BD: I just started, really, testing a lot of the technologies that were out there. Most of what’s around today is focused on maintaining the pressure of the ball—enclose them before they lose their bounce. And that’s a good option, especially for recreational players. But it’s not a bulk solution; it’s not geared toward tennis professionals or teams who are really going through a lot of balls. So I believe it was ’98 or ’99, I started working on it; and then, in 2007, I filed the first patent for a bulk apparatus to recharge tennis balls. I’m a tinkerer by trade. I’m not one of those guys who’s afraid to fail, I guess. It was just a lot of trial and error, to be quite honest.  

JD: Other than the products aimed at maintaining ball pressure: What else did you consider during the design process?

BD: I looked at a lot of patents that were out already there. One patent, it involved a needle that would inject air and a sealant into the ball, to plug the hole. It was kind of like a fix-a-flat, which was really what it was. I tried that and, of course, I could never get it to work properly. After it dried, it seemed liked the sealant would weigh [down] one side of the ball. It’d be warped and wouldn’t bounce properly. I didn’t see any practical, commercial application of that. You might be able to get a ball to seal and be fine for a few. But you know, the air’s still going to leak out of the ball in other places, because the membrane of the ball is permeable. So over time, you’d just have to do it again.

JD: Wait, but you were doing all this work, testing materials and making prototypes, in your garage?

BD: Yeah, I had a shop building where I lived. And this was while I was coaching and teaching school. I felt a bit like the crazy professor out there, just trying all sorts of gas blends and things that didn’t work. Actually blew a window out of the shop building one night. That was kind of fun.

JD: What happened?

BD: I was trying some different materials and different gases on the compression, and just had a tank rupture. It wasn’t that big of a deal. No one was hurt. It was scary for a moment. That’s why we stress—all of our devices are ASME [American Society of Mechanical Engineers] Certified. They’re overengineered for safety, and have built-in redundancies. [Even though] the pressure that we use, in the grand scheme of things, is not that high. We also use an inert gas that isn’t flammable.

JD: With as much detail as you can say: How exactly does the machine function? I understand it has to do with putting the balls under a certain amount of pressure.

BD: Well, we put the balls in a chamber pressurized by an inert gas. And after a certain amount of time, this forces the dense molecules through the cores of the balls until they’re back to industry pressure and a bounce that complies with ITF regulations: 53 to 58 inches of rebound height when dropped from 100 inches.

JD: So that’s just the physics of it? There’s a pressure gradient, and the ball inflates the longer it sits in the chamber?

BD: Right. They’re designed to hold a certain amount of pressure; basically, tennis balls themselves are pressure vessels. We set the machine to work over three days, so all the balls are able to equalize and come out at the same pressure. Certainly, you could pump them up faster [than three days.] But you would have some inconsistencies, if you didn’t allow them the time to equalize.

JD: But say you took a new ball and threw it back into the chamber for another three days of recharging: Would the ball inflate such that it exceeded the ITF-regulated bounce? Or would it stay at the standard bounce height?

BD: If you allow the balls to go longer than the cycle, they can get slightly overpressurized. But the ball can only hold so much pressure. We’ve had people forget about them. You just have to wait. In about a day, they’ll drop down to their original pressure.

JD: How much more pressure could you potentially get into the ball? Say you’re about to play a backboard-like player, and you really want your ball to go.

BD: [Laughter] It depends on the ball, but you could probably get, with a new one, a couple of psi [pounds per square inch] out of it. Which might equate to a three- to five-inch difference in rebound height.

JD: Your company reBounces, it does more than just make Green Tennis Machines, right?

BD: Really, when we launched reBounces, we started with a tennis ball recycling campaign, which we launched on-site at the BNP Paribas Open a few years ago. It’s grown from 5,000 balls, I think, that first year to over 140,000 balls last year.

JD: Oh, so you brought the GTMs to market after the recycling program was already on its way?

BD: Yes, we provided a recharging service to a few clients as we were testing out the idea. At the same time, we were putting our name out there as a green leader in tennis. And we still are to this day: We collect tennis balls from sites, and in certain quantities we’ll cover the shipping. Then, we’ll either provide those to our clients who have a Green Tennis Machine and can recharge them on their own. Or, we’re also working on the whole lifecycle of the tennis ball, and are actually looking at grinding [balls] up and using them in the subsurfaces of tennis courts.

JD: You said earlier that you filed your first patent in 2007. When was it awarded?

BD: It was [about] four years before that was granted, the first patent.

JD: Really.

BD: Yeah, I had made the prototypes, which worked and weren’t much different from the ones we have right now. Certainly, the current ones are designed better, and are easier to use. And they have a better aesthetic to them. When we filed our first patent, I believe it was June of 2007; it was 2011 when I first was awarded that patent. It takes some time. And there’s certainly a financially aspect to it as well.

JD: Just trying to gather the capital to start a company?

BD: Right. There’s a lot of work in that. I’m really proud of the people I’ve brought on to help me build the company. There are five of us, full time. And then we have some folks that help out consulting or part-time. I’ve got dedicated people who really believe in the idea.

JD: Are there any initiatives you’re looking to launch in the future, above and beyond the three GTMs you currently offer?

BD: I don’t really want to mention specifics. But obviously right now, we’re focusing on teaching professionals. I’ll just say: It won’t be long down the road that we’re offering some products that may appeal to your basic tennis enthusiast.

JD: So we may soon see a few GTMs at a price point suitable for recreational players?

BD: I’ll leave that to you. I’m not going to comment on that.

JD: How is the industry reacting to the devices? Do you have a sense of how tennis-ball manufacturers feel about your products?

BD: Well, I don’t know how much they consider us. But we feel like we’ve got a lot of common ground. We’re all about growing the game and making it accessible to everyone—getting more people playing and enjoying tennis. And we think that’s good for the tennis industry. There are a lot of great things going on in the industry—from to Quickstart, the new 10 & under initiative. [Note: GTMs also recharge Quickstart balls, albeit in a shorter cycle.] We’re just thrilled by it, and we think it’s going to make a lot of lifelong tennis players, which is good for us [and the industry].

When I was growing up, the green aspect wasn’t something I thought about. But with the years behind me, I think a lot of decisions about how our kids spend their time, energy and the money are affected by [issues of] sustainability. Right now, my kids have so many different organized activities competing for their time. And I think being able to promote tennis as sustainable could be a really important [in the future] to growing the game.

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