You pick up a paddle. It looks nice. Cool logo. Maybe bright colors.

But inside your head, you’re still asking:

“Is this fiberglass or carbon fiber?”

You care because you want to pick the right paddle for you, your players, or your customers:

Fiberglass usually gives more pop and power, but a bit less spin and may wear out faster.
Carbon fiber (especially raw T700) usually gives more control, softer feel, better spin, and longer life.

The problem? Many paddles just say “composite” on the label. So you need a way to check for yourself.

Good news: you don’t need a lab. You only need:

A flashlight (your phone is fine)
A ball
Your eyes, your ears, and a few minutes

There are three easy checks you can use:

Light test – can you see light through the face?
Sound test – what sound do you hear when you hit the ball?
Surface test – what does the face and the artwork look like?

Let’s walk through each one in simple steps so you can use them right away.

First: What’s the Big Deal About Fiberglass vs Carbon Fiber?

Before you test, it helps if you know what you’re looking for.

Fiberglass – “Pop and color”

When you choose a fiberglass face, you usually get:

A face that is softer and more flexible (it bends more when the ball hits)
More rebound and pop – the ball jumps off the face with extra power
Often big, full-color prints and shiny surfaces
Good all-around play, but usually less spin and smaller sweet spot compared with top carbon paddles

Carbon fiber (especially raw T700) – “Spin and control”

When you choose a carbon fiber face, you usually get:

A face that is stiffer and stronger (it doesn’t bend as much)
More control and softer feel in your hand – the face spreads the impact across the paddle
Better spin, especially with gritty raw carbon surfaces
Usually dark, matte, fabric-like surfaces with a “tech” look, often labeled as “Toray T700 raw carbon” or similar

So when you ask, “Is this fiberglass or carbon?” you are really asking:

“Do I want more easy power and loud color, or more spin, control, and long-term performance?”

Now let’s see how you can tell them apart.

Method 1: Flashlight Test – Can You See the Light?

This is the simplest test. You can do it in a shop, in your club, or in your warehouse.

How you do it

Take out your phone flashlight.
Go to a spot that is not too bright.
Put the light right behind the paddle face (on the back side).
Look at the front side of the face.

What you’ll see with fiberglass

When the face is mostly fiberglass:

The paddle lets some light pass through.
You may see a soft glow in the center.
In some paddles, you can even see a shadow of the honeycomb inside.

Fiberglass is more translucent, so light can sneak through the layers.

What you’ll see with carbon fiber

When the face is real carbon fiber

The face is almost fully dark.
The light barely comes through the middle.
Maybe you see a tiny bit around the very edge, but not across the face.

Carbon fiber sheets are much more opaque, so they block the light.

Simple rule for you

If you see the face glow with light, you’re probably holding fiberglass (or a glass-heavy mix).
If the face stays dark, you’re probably holding carbon fiber.

This one trick already gives you a strong first clue.

Method 2: Sound Test – Ping vs Thock

Now you use your ears.

Different face materials vibrate in different ways. That vibration becomes the sound you hear when you hit the ball.

How you do it

Take a paddle and a ball.
Hold the paddle in your normal grip.
Bounce the ball gently on the sweet spot (middle of the face).
Then bounce closer to the top of the face.
Listen to the sound carefully.

If you can, you should also compare:

One paddle you know is fiberglass
One paddle you know is carbon fiber

When you do that, the difference pops out very quickly.

What fiberglass usually sounds like

The sound is more sharp and bright.
Many players call it a “ping”.
When you hit harder, the sound can ring a bit and feel louder.

That extra flex in fiberglass sends a lot of energy back into the ball – and also into the air as sound.

What carbon fiber usually sounds like

The sound is more low and quiet.
It feels like a “thock” or “dunk”, not a high “ping”.
The sound dies out faster and feels more solid in your hand.

Carbon fiber spreads the impact across the face, absorbs some energy, and often works together with thicker cores and foam walls to reduce vibration.

Simple rule for you

If you hear a high, bright “ping”, you’re likely on fiberglass.
If you hear a low, solid “thock”, you’re likely on carbon fiber.

If you buy for a club, a brand, or a shop, you can record short sound clips on your phone. When you play them back side-by-side, you will hear the pattern very clearly.

Method 3: Surface Test – How Does the Face Look and Feel?

Now look closely at the face itself. This is where you see the biggest visual difference.

There are two parts you care about:

Texture – how the face looks and feels
Printing – how much artwork covers the surface

3.1 Texture: matte, gritty vs shiny, smooth

Most raw T700 carbon paddles look like this:

Dark, matte (not shiny) surface
A fabric-like weave pattern or fine texture you can see when you tilt it in the light
A face that feels grippy or slightly rough when you slide your fingers over it

Brands that use raw T700 carbon (or similar) often promote that gritty, matte surface because it holds the ball and creates spin.

Most fiberglass paddles look like this:

Smooth and glossy surface
You usually do not see the fiber weave under the paint
Your fingers feel more like sliding on a car’s painted hood

The fiberglass face does its job by flexing for power, so the top is often just a printed and clear-coated layer.

3.2 Printing: full artwork vs simple logo

Look at how much of the face is covered in design.

Carbon fiber paddles (especially high-spin T700) usually:

Keep the face mostly dark and clean
Use a small logo, simple text, and light accent art
Try not to cover the whole surface, so the raw texture stays open for spin

If a brand cares about spin and grip, it doesn’t want to bury that gritty carbon under thick ink.

Fiberglass paddles usually:

Use big, full-face graphics from edge to edge
Show bright colors, pictures, or wild patterns
Treat the paddle face like a big art board

This makes them stand out on a shelf and is easy to do on a smooth fiberglass surface.

3.3 Watch out for “fake carbon” prints

Some low-cost paddles use fiberglass faces with a printed carbon pattern on top.

When you see a fake pattern, it often:

Looks too perfect and too flat
Doesn’t change much when you tilt the paddle in the light
Loses its “carbon” look the moment you do the light and sound tests

Here’s where you use all three methods together:

If it looks like carbon but glows with the flashlight and pings like fiberglass, it’s probably not true raw T700 carbon.

How You Can Use These Three Checks Together

When you test a paddle, don’t stop after the first trick. Use them as a small “inspection routine”:

Light Test
- Light passes through the face → you mark it as fiberglass-side.
- Face stays dark → you treat it as carbon-side.
Sound Test
- Bright “ping” → pushes your guess toward fiberglass.
- Soft “thock” → pushes your guess toward carbon.
Surface Test
- Dark, matte, gritty, simple logo → looks like T700 carbon style.
- Glossy, full-color art, no visible weave → looks like fiberglass style.

If all three say the same thing, you can be very sure without even seeing the factory drawing.

What This Means for You as a Player

When you understand these differences, you can:

Choose more pop and power with fiberglass, if you like to drive the ball hard and don’t mind a bit less spin.
Choose more control and spin with carbon fiber, if you like to shape the ball and play with touch at the kitchen.
Match the paddle to your own style, not just to the color or to a friend’s suggestion.

You don’t have to guess from the marketing words. You can use your own eyes, your own ears, and your own simple tests.

What This Means for You as a Coach, Club, or Brand

If you run a club, a shop, or a paddle brand, these checks help you even more:

You can check samples from factories as soon as you open the box.
You can see if a “T700 raw carbon” label really feels and looks like carbon, or if it behaves more like fiberglass.
You can explain to your players and buyers why one paddle feels softer, why one sounds louder, and why one keeps its spin longer.
You can protect your brand by choosing the right builds and by rejecting samples that don’t match the promise.

Keep one “known fiberglass” paddle and one “known raw carbon” paddle on your desk. Whenever you get a new sample, you:

Do the flashlight test
Do the sound test
Do the surface test
Compare with your two reference paddles

In a few minutes, you know what you’re really holding.

Final Wrap-Up: Three Simple Tests for You

Any time you want to know, “Is this fiberglass or carbon fiber?” you can:

Shine a light
- Light through the face = likely fiberglass
- No light through the face = likely carbon fiber
Listen to the hit
- Bright “ping” = likely fiberglass
- Soft “thock” = likely carbon fiber
Study the surface
- Dark, matte, gritty, simple print = T700-style carbon
- Shiny, smooth, big full-color art = fiberglass