7 Lessons We’ve Learned from Making Disc Golf Discs

From an outside perspective, making discs might seem pretty straightforward.

I mean, it’s just a plastic circle.. Right!?

Well, ever since we started making discs out of Jesse’s garage, we’ve learned that this could not be further from the truth.

So we wanted to share seven of the biggest lessons we’ve learned over the past 4 years in ~4 minutes.

Starting with the fact that:

1: Disc Golf Discs Break the First Rule of Injection Molding

In traditional injection molding, rule number 1 is to inject from thick to thin. 

Whether you’re making bottle caps, buckets, or anything else, injection molding is optimal when the plastic can flow from the thickest wall to the thinnest wall.

Discs, however, responded, “Hold my beer.”

When making discs, you actually start from the thinnest part (the flight plate) and move to the thickest (the outside rim), defying this rule and making them exceptionally hard to produce. Hence the little circular injection point on the bottom center of most discs. 

One interesting exception to this is overmolding. By injecting the rim and flight plate separately, you effectively eliminate the challenges mentioned above. Overmolding still presents other challenges, so it’s not to say it’s easy. It just eliminates some of the problems that stem from breaking injection molding rule number one.

2: Witness Marks Tell the Story of How a Disc Was Made

Ever notice a mark on your disc that’s not an engraving?
Like the aforementioned “injection point” on the bottom center of the flight plate? 

Well this might seem obvious, but discs with visible injection points are typically injection molded and discs without, like Vibram or Elevation, are made using a different process like compression molding. 

But it gets muuuuuch more interesting than that.

Case in point: air poppets!

If you look at the bottom of an Inner Core or almost any MVP disc or at the top of a looooooot of Trilogy discs, you may see some little circles that are evidence of a thing called an “air poppet” in the mold.

Air poppets help eject the disc from the mold itself because plastic can be very suction-ey (is that a word?), so manufacturers use them to force air to a very specific part of the disc to make it fall off of the mold in a very specific way. 

As an added bonus, this creates for repeatability and even automation, which allows robots (the fun kind, not the scary kind) to pick them up from the same spot every time and move them around to the next step in the process. 

Bottom line: if you were to hand a disc to someone who knows plastic molding, they’d identify different witness marks and likely be able to tell you exactly how the disc was made.

And if you pay close enough attention to things like this, you’ll have the most niche party trick ever: being able to tell who makes a disc by feel alone (but you’ll probably stop being invited to parties, unfortunately).

3: Mold Changes are Time-Consuming

Almost all disc golf discs are made in single cavity molds, which means you can only make one disc at a time.

So what happens when manufacturers want to switch to making another type of disc??

We undergo a 4-hour, labor intensive process to swap the 750lb mold out for a different one, taking our sweeeet time because any mistake in this process can cost tens of thousands of dollars.

Some of the steps include, but are not limited to:

-unhooking the water lines,
-using a forklift to remove the $25,000 mold,
-cleaning the machine,
-changing nozzles if needed,
-installing a different $25,000 mold, and
-configuring the machine.

Yeah.. to say it’s “nerve wracking” is an understatement.

4: Tiny Design Changes Have Big Effects

The flight of a disc is all about aerodynamics, which means even the smallest changes in the design of a disc can significantly affect its flight characteristics. 

At Trash Panda, we use computational fluid dynamics to help us design our molds, and it’s always surprising just how much one tiny variable can affect things. 

For instance, when we tested the difference between a concave rim-profile and a flat rim-profile on the Ozone (our flippy fairway driver), it resulted in a COMPLETELY different predicted flight.

Couple that with plastic type, cooling, and other environmental factors and you have about 10,000,000 different things (give or take) to think about when trying to design the perfect disc.

5: What Actually Causes Flashing

Flashing occurs when excess plastic seeps through mold seams due to high pressure during injection molding.

Maybe the most surprising thing to us was how common it is outside of disc golf. (There are literally tools made to trim flashing.)

Flashing on a plastic products is mostly a result of wear and tear on the molds over time or due to the pressure of injection being more powerful than the clamping pressure.

But discs are special.

Remember when discs said “hold my beer” and decided to be injected from thin to thick?

In order to fill the thick outer walls, discs are much more susceptible to flashing than other injection molded parts.

The result?

Many disc golf manufacturers (including us) accept flashing as a part of the process, and just trim it when necessary.

In fact, we have a "Screw of Perfection" in our warehouse where we memorialize every time flashing is removed from a disc in one piece! Marvel at it here.

6: Plastic is… Complicated

T.P.U.

Seems pretty simple, right?

Premium discs are primarily made from a plastic called Thermoplastic Polyurethane (TPU), and just like a disc itself, it’s much more complicated than meets the eye.

There are many sub-variations within the “TPU” category (like different durometers), which means you could make a soft and floppy disc along with a disc that is rock hard – yet both are from TPU!

If that wasn’t enough, different batches of the same TPU can feel completely different and it’s hygroscopic (meaning it absorbed moisture from the air).

Whether or not you’re using virgin or 100% recycled plastic - like us - TPU is just about as complex as it gets.

Don’t believe us still? 👇

7: Green Discs Can Be More Overstable

Over the years, disc golfers have noticed that different colors fly differently.

So the question stands: do different colors affect the flight of a disc?

Well, yes and no.

Yes because different colors affect the processing in the machine, which means different parameters might change during the molding process and thus have an effect on the flight of the disc.

Crazy, right?

Color 100% has an effect.

But that doesn’t mean that green is more overstable.

Instead, it just means that you could have a green disc that acts more overstable but you could also have a green disc that doesn't.

Color affects the process and the process affects the flight.

The more you know!

It’s all so worth it. 

Our journey in disc manufacturing has been a continuous learning experience. 

From overcoming the challenges of injection molding to understanding the complexities of using 100% recycled plastic, each lesson has shaped our approach and improved our products. 

Making discs is no easy task, and using recycled plastic only adds to the complexities.

But growing the sport sustainably is worth it.

And we’re so stoked for this list to continue growing as we learn more and more each day.

For a more in-depth look at what we talked about in this blog, check out this YouTube video ⬇️