Introduction: How to Make a Carbon Fiber Phone Case

Welcome to my instructable on making a carbon fiber phone case!

I will be showing you how to make a custom phone case that fits your phone and looks cool!

A little while ago I thought to myself: "Self, what would be cooler than a sleek carbon fiber phone case?" and I said "Well other self, we have to make one in lab anyways so I guess making it ourselves makes it pretty cool."

By the next Friday we were measuring and cutting carbon fiber sheets and making epoxy, and I realized that while it was pretty self explanatory, a nice E-how would've made the project a little easier. There are plenty of videos on YouTube that do similar lay ups, and even companies that sell carbon fiber have been known to make videos. But I like to read an instruction manual when I put things together, which I attribute to my days putting Legos together. So here I am, sharing with all of you my own, written instructable on making your own, super cool, glossy, show-offable, carbon fiber phone case.

Let's get started!

Step 1: Things You Will Need

For this project, most of the supplies are pretty straight forward. Carbon fiber and epoxy are obviously needed, but some extra things that you'll need may include plaster, a vacuum bag, something to hold your phone case up to not get any smudges on it, and a Dremel tool.

The Epoxy and hardener are toxic, and the Material Safety Data Sheet is linked below:

The other stuff I used was:

Press and Seal


Plastic wrap

A hammer

Vinyl and Nitrile gloves

Safety goggles

All of these steps require goggles and some sort of gloves, which are specified on each particular step.

Step 2: The Plaster Mold

For those starting with a phone case as a mold, one way to set up your carbon fiber lay out is to make a plaster mold of the case you are copying. This has the benefit of not ruining your phone case, and makes separating the carbon fiber from the mold easier.

To start, take your phone case and line the inside with press and seal. Make sure to avoid wrinkles, as they will impact the plaster; and leave some slack around the holes of the charging port, speakers, and whatever other features your phone has along the edges. This keeps your phone separate from the plaster, and helps keep dirt from your phone case out of the plaster mold.

From here it's as easy as filling the press-and-seal lined case with the plaster. Think of it like filling a cake tin, making sure to get all the corner filled and having a nice flat surface. And now we wait for the plaster to harden.

Step 3: Separating the Plaster From the Case

This step is straight forward, but if done wrong can set you back a day.

When separating you plaster from your phone case, take extra care to not break the plaster mold! I was able to get it out without a problem by giving it a gentle twist and popping it out with a tongue depressor.

Peel off the press and seal, and set aside your old phone case as you won't be needing it from this point on.

Take the same tongue depressor and shave off the edges of the plaster case. There may be a small lip at the top which is important to shave off, and keeping all the edges level makes the final case turn out more uniform.

Step 4: Cutting the Carbon Fiber

IMPORTANT: Use Vinyl gloves for this step, and wear a long sleeve shirt and goggles. The carbon fiber can irritate skin, avoid scratching if you get itchy.

The first step in a custom phone case is making sure that the case will fit! And the best way to do that is to cut out enough carbon fiber to fit around the edges, with a little bit of wiggle room to get the phone in and out. To make it even easier, using a phone case that you know fits your phone well as a mold for the carbon fiber. Don't cut too much though, as you won't be able to get you casting off of the plaster mold. I shot for half an inch to an inch off of the edge of the plaster.

As my lead carpenter taught me: measure twice, cut once.

To help prevent the carbon fiber from fraying as you cut the sheet, put a piece of tape on the carbon fiber sheet and cut through the middle of the strip of tape.

Add a layer of wax paper between the carbon fiber and the plaster as a barrier. This will also help keep the plaster from getting into your phone case.

To keep the carbon fiber from sprawling out as you wrap it around the plaster, taping down the the carbon fiber and then taping the edges together works. To keep it extra sealed, add an extra piece of tape going from tape to tape.

Step 5: Making the Epoxy

IMPORTANT: For this step, use Nitrile gloves. The epoxy is dangerous

Now that the carbon fiber is wrapped to the plaster mold, we need to add epoxy to reinforce the carbon fiber. There's a whole lot of materials science that goes into making a composite with fibers(carbon fiber) in a matrix(epoxy), but that's beyond the scope of this instructable. Just know that the epoxy keeps it strong in every direction, instead of just fibers that are really strong in one direction.

For my epoxy I used three part Fiber Glast 2000 Epoxy Resin to one part 2120 Hardener mixed the hardener INTO the epoxy, and stirred it with a tongue depressor. You want to stir until the mixture looks like one continuous matrix, and make sure to avoid under stirring.

Step 6: Applying the Epoxy

IMPORTANT: When handling epoxy, use nitrile gloves

Now that your epoxy is mixed, is a small race against the clock depending on which hardener you used. In my case, a 2 hour epoxy was more than enough time, but a 30 minute epoxy may be cutting it a little close.

Using any sort of brush, liberally apply epoxy to the carbon fiber. The biggest contributor to the strength of your case is how well the matrix and fibers work together, and in this case they work together when the epoxy gets well mixed with the fibers.

IMPORTANT: Disposal is incredibly important. Every piece that touches the epoxy place in dedicated waste bin.

Step 7: Vacuum Sealing the Phone Case

IMPORTANT: Again, while handling epoxy use nitrile gloves.

Take your nice epoxied phone and get ready to put in a vacuum sealer. This technique helps get the excess epoxy off and makes the bond between the epoxy and fibers much stronger.

Note: Maybe not use the nicest vacuum pump, and the epoxy that gets into it may damage it. Again, there are many videos describing how to properly set up and use the vacuum pump. The way I did it is one of many.

IMPORTANT: Excess epoxy must be disposed of properly

Step 8: Removing the Case From the Plaster Mold

If you didn't use the plaster mold, feel free to skip ahead.

At this point you phone case will be solid and can be handled without gloves, but take care around the sharp edges.

To remove the plaster from the phone case, carve the carbon fiber off the edges of the plaster then get a nice hammer and go to town. Avoid hitting to hard to break the phone, but give some nice swings to break apart the plaster mold and dispose of it. Make sure to get all of the plaster and wax paper out of the case! I used needle nose pliers to pull out the corner chunks of plaster and wax paper.

Step 9: Cleaning Up Your Case

IMPORTANT: Be careful around the Dremel tool, and loose hair or articles of clothing can get caught and can lead to serious injury.

Take the Dremel tool and clean up the edges. Using a sanding tool to makes your edges straight and your corners rounded, and an engraving tool to put holes where you need them (speakers, charging port, etc.).

If you go too fast with the Dremel tool, you run the risk of damaging your case. Start slow, and slowly work your way up in speed.

If a layer of epoxy is still on your phone, it probably came from the vacuuming process. You can carefully remove it with a sanding tool, or simply trim the edges to lay flush.

Step 10: The Glossy Coating

Clean the back of your phone case very well, and add another layer of epoxy. You don't need to be as liberal this time, as the strength of the case won't change much in this step. This is more to make the back nice and shiny. Feel free to lay some on the inside of the case as well to make the whole case glossy. Avoid putting the phone on something that could disturb the epoxy like a moving counter top. My suggestion is find a way to hang it out to harden with a sheet of wax paper below.

Step 11: Finishing Touches

Congratulations! You've made your own carbon fiber phone case. From here all that's left is to put it on your phone and show it off to all of your family and friends.

Enjoy! And don't forget to dispose of all of your extra epoxy properly!