Introduction: Custom Molded Carbon Fiber Phone Case


This purpose of this instuctable is to show how to create a custom case for a phone out of carbon fiber sheets and epoxy.


The epoxy poses a chemical hazard as it can be harmful for your skin, eyes, and nose. Wear proper personal protective equipment (PPE) when handling the epoxy, including (but not limited to) a rubber apron and gloves. Consult a glove chart to ensure that the gloves are compatible with the epoxy.

The epoxy and hardened carbon fiber pose a mechanical hazard as well. Epoxy is incredibly difficult to remove from anything once it sets, so handle it with proper care. The hardened carbon fibers can be sharp and if they are cut into small pieces, the tiny fibers can get on your skin, which will be very itchy and hard to wash off.

Step 1: Gather Materials

Personal Protective Equipment:

Dust mask

Nitrile gloves for epoxy (check compatibility on glove chart)

Rubber or other protective apron

Vinyl loves for plaster

Plaster Case Mold:

16oz plastic cup

3oz dixie cups

Cold water

Glad Press'n Seal wrap

Paper towels

Phone case

Plaster of Paris (DAP brand or other)

Saran Wrap

Carbon Fiber Case:

Plaster phone mold

16oz plastic cup

3oz dixie cups

Adhesive strips for vacuum bag edges (Fibre Glast or other brand)

Carbon Fiber Sheet (approximately 0.5 square foot per phone)

Epoxy Resin and Hardener (Fibre Glast or other brand)

Foam brush

Masking Tape

Vacuum bag

Vacuum nozzle/hose attachment

Vacuum pump

Wax Paper

Wooden popsicle stick or craft sticks

Step 2: Prepare the Area

Cover the work area in a sheet of saran wrap and tape down the edges.

Place the phone case in the work area with the inside facing upwards.

Put on your rubber apron and vinyl gloves.

Step 3: Apply Glad Wrap

Cut out a sheet of Glad Press'n Seal Wrap.

Press the sheet around the inside of the phone case.

Push a little extra of the sheet into any holes in the case, such as where the charging port or the camera hole are located.

Try to make sure that there are few bubbles or wrinkles, and pay special attention when wrapping around the corners.

Step 4: Prepare the Plaster

Measure out approximately 3oz of plaster by volume in a dixie cup. Then transfer to the large plastic cup.

Add a small amount of cold water to the 16oz plastic cup and stir thoroughly with a wooden popsicle stick.

The consistency of the plaster should be thick, but still easily pourable. Make sure there are no lumps in the solution.

Continue adding water and stirring until the consistency of the plaster seems correct.

Step 5: Create the Plaster Phone Mold

Pour the plaster into the cell phone case covered in Glad wrap.

The entire case should be full of plaster, and no lumps or bumps should be visible along the top surface. If there are lumps, try to smooth them out with a popsicle stick.

Let the plaster set over the course of 24 hours.

Step 6: Remove the Plaster Mold From the Case

After the plaster has set, gently try to remove the plastic phone mold from the phone case.

Start at the most flexible part of the case, which is usually the corners.

Be careful not to break the mold.

Once it is removed, use a wooden popsicle stick and water to polish down any sharp edges. This mold should resemble the original phone.

When done, set it aside for later use.

Step 7: Prepare the Workspace

Tape down saran wrap all around the work area.

This next process involves epoxy and carbon fibers, both of which can poses hazards. Wear compatible nitrile gloves and a rubber apron.

Step 8: Cutting the Carbon Fiber

Measure the dimensions of your phone (Length x Height), and add an extra inch and a half to each dimension.

Tape out those dimensions on a sheet of carbon fiber. Cut in the middle of the tape, as the tape will keep the edges from fraying and the fibers from separating.

Lay out the carbon fiber sheet in your workspace.

Step 9: Prepare the Phone Mold

Cut out a sheet of wax paper that is the same dimensions as the carbon fiber sheet from before.

Carefully wrap it around the phone mold, and tape down the edges.

Leave a gap in the center of the phone mold, as this will make it easier to remove the carbon fiber lay up from the phone mold later.

Step 10: Lay Up the Carbon Fiber

Wrap the carbon fiber sheet around the phone mold.

Make sure the corners of the wrapped case look good.

Tape down the edges to hold it in the desired position, and ensure that the wrap is secure.

Step 11: Mix the Epoxy

Measure out 45mL of the fiberglass resin by volume in one 3oz dixie cup.

Measure out 15mL of the fiberglass hardener by volume in another 3oz dixie cup.

Carefully pour the resin and hardener into the 16oz plastic cup. Use a wooden popsicle stick to scrape any remaining fluid from the dixie cup into the plastic cup. Mix by stirring thoroughly for at least two minutes.

Step 12: Apply Epoxy to the Carbon Fiber Case

Apply epoxy to the front of the carbon fiber case using the foam brush. Avoid putting any epoxy in the middle of the case where there is a gap.

Brush around the edges of the case.

Be sure to saturate the fibers so that the final case will be mechanically sound.
Flip the carbon fiber case so that the back is facing up, and set it on an object you can throw away.

Brush the back, and work the epoxy into the fibers.

Step 13: Prepare the Vacuum Bag

Cut out a sheet large from the vacuum bag roll that is large enough to fit the phone case. If doing this process in bulk, cut it out large enough for all of the cases.

Cut out a piece of the vacuum bag seal tape with an extra inch or two on each side. Remove the adhesive and and seal only one side of the bag.

Put the vacuum nozzle and hose attachment on the bag.

Cut out a another piece of the vacuum bag seal tape of the same length. Put it along the other edge of the bag, but do not seal it yet.

Place the phones into the vacuum bag. The corners and edges are the best locations. Be careful not to get any epoxy on or around the seal tape, as it will make the bag hard to seal.

Step 14: Seal the Vacuum Bag

Remove the adhesive strip from the vacuum bag seal tape.

Start by pressing firmly in the middle, then moving outwards towards the edges. If there are any wrinkles, try to reseal that small area so no air will leak through.

Step 15: Attach the Vacuum Hose

Push the vacuum hose onto the nozzle adapter until the fit is secure.

Seal the connection with more of the vacuum bag seal tape.

Step 16:

Step 17: Turn on the Vacuum

Plug the vacuum pump into the wall, and turn the power on.

Listen and look for any leaks in the vacuum bag, and try to seal them if you can.

Push any bubbles visible on top of the carbon fiber case away so that the bag and the case have full contact.

Let the vacuum pump run for at least a couple of hours, or as long as it takes for the epoxy to dry.

Step 18: Carbon Fiber Case Preparation

Once the epoxy has dried, remove the carbon fiber case from the vacuum bag.

Put on the dust mask for this step.

Crack the plaster with a hammer and remove the remnants with a screwdriver. Use a dremel to cut out any holes in the case, such as for the charging port, volume buttons, or camera hole.

If a shinier finish is desired, make more epoxy and apply it to the carbon fiber phone case. Let it dry for at least two hours.

Step 19: Carbon Fiber Phone Case

Congratulations! The Carbon Fiber phone case is finished.