DIY Carbon Fiber Phone Case

The purpose of this instructable is to demonstrate how to successfully lay-up a carbon fiber molded phone case out of epoxy resin and carbon fiber sheets.

Hazards/Cautions/Precautions:

Long pants and clothes toed shoes are advised. Long hair should be pulled back and away from face. Proper gloves and safety glasses/goggles should be worn at all times when making your phone case.

Caution should be taken when using epoxy and hardener. Cured epoxy poses hazard to your skin, eyes, and clothing fabrics. It is important to wear the proper Personal Protective Equipment (PPE) during epoxy usage. Epoxy should be handled with care because once it sets, it is forever.

Handling carbon fiber sheets may cause irritation (itching and/or redness) to exposed skin. To prevent skin irritation, it is recommended to wear long sleeves and a face mask.

The Dremel tool is very sharp and can promote excess material debris during use. A dust mask is highly suggested.

Sources of Error:

Common sources of error arise from improper water to plaster and epoxy to resin ratios. Incorrect measurements for mixing may cause undesirable results, such as a brittle or lumpy plaster mold and bubbly or tacky epoxy coating. Error may also result from not fully impregnating the carbon fibers with epoxy during lay-up and not completely sealing the vacuum bag and value during processing.

Personal Protective Equipment (PPE):

• Vinyl gloves for general use
• Nitrile gloves for epoxy
• Proper clothing
• Dust mask
• Safety glasses or goggles

Phone Case Materials:

• Phone Case
• Saran Wrap
• Wax Paper
• Glad ClingWrap
• Paper Towels
• Masking Tape
• Carbon Fiber Sheet
• Plaster of Paris (DAP brand was used)
• Epoxy Resin and Hardener (Fibre Glast brand was used)
• 16oz plastic cups
• 3oz paper cups
• Wooden popsicle sticks
• Two sided adhesive strips for vacuum bag edges
• Vacuum bag
• Vacuum pump, hose, and valve
• Foam brushes

Tools:

• Hammer
• Scissors
• Tweezers
• Dremel power tool with cutting, sanding and buffing bits

1. Clear workspace.

2. Cover the workspace with a sheet of saran wrap, pulling tight and taping down the edges.

3. Place the phone case in the workspace with the backside laying on the table and the inside facing upwards.

1. Prepare phone case.
   • Tightly line the inside of the phone case with Glad ClingWrap.
   • Push extra wrap through any holes in the phone case (e.g. camera location, charging port, speaker location, etc).
   • Press firmly and try to remove all bubbles and/or wrinkles, especially at the corners of the phone case.
2. Prepare the plaster.
   • Mix plaster in accordance to ratios given by the company. In this case, 1 part water by 2 parts DAP plaster were used.
   • Fill a 3oz paper cup with plaster powder. Then, transfer the powder to a 16oz plastic cup. Reuse the 3oz cup and slowly begin to add water to the mixture.
   • While slowly adding in water to the plaster powder, stir with a wooden popsicle stick. Continue adding water until the consistency of the solution is similar to pancake batter (thick, yet pourable).
   • Make sure there are no lumps in the final mixture.
   • If plaster to water ratios are off, you can always add a little more of one or the other.
3. Pour plaster into prepared phone case.
   • Using a wooden popsicle stick, evenly spread the plaster throughout the phone case. Be sure to completely fill the phone case. The plaster should lay even with the top lip of the phone case.
   • Make sure that no bubbles or clumps are within the plaster. Use the wooden popsicle stick to smooth out all bubbles and/or lumps, if possible.
   • Let the plaster set 24 hours before continuing to the next step.

After the plaster is completely dry:

1. Carefully remove the plaster mold from phone case and ClingWrap.
   • Push the mold out of the phone case. It may be easier to start at the corners of the phone case.
   • Be careful not to break the mold.
2. Sand down mold.
   • Using the edges of a wooden popsicle stick, sand down the sharp edges and appearance of wrinkles from the mold surface.
   • The mold should be smooth when finished.

1. Cut a sheet of wax paper according to the dimensions of the phone mold.
   • Wax paper should be cut large enough to wrap over the edges of the phone mold.
2. Carefully wrap the wax paper around the edges of the phone and tape edges of paper to the mold.
   
   • When wrapping the wax paper, try to avoid a large amount of wrinkles, creases and/or folds.
   • Leave an open space at the center of the prepared phone mold.

1. Prepare a new workspace.
   • Remove saran wrap from the work area and dispose in waste bin.
   • Apply new saran wrap to workspace using techniques discussed in Step 3.
2. Measure out a sheet of carbon fiber to the dimensions of the wax paper wrapped phone mold.
   • Be sure to add an extra 1" to the dimensions for wrapping purposes.
   • Tape out the dimensions measured and carefully cut down the center of the tape. The tape prevents the edges of the carbon fiber from fraying or unraveling.
3. Lay the carbon fiber flat on your prepared workspace.

1. Wrap the carbon fiber sheet around the phone mold, much like Step 5 with the wax paper.
   • Make sure there are no wrinkles present in the corners of back of the case.
2. Tape down the edges of the carbon fiber sheet.
   • Be sure to tape the carbon fiber in the exact way desired for the final phone case product.
   • Leave the center of the phone mold open/exposed for easy removal of plaster in later steps.

1. Measure out 3:1 volume ratio of epoxy resin and hardener.
   • In a 16oz plastic cup, measure out 60mL of epoxy resin and set aside.
   • In a 3oz paper cup, measure out 20mL of hardener.
2. Slowly pour the 20 mL of hardener into the 60 mL of epoxy resin. Stir the solution with a wooden popsicle stick as the hardener is being poured.

   • Pour and stir slowly so that no bubbles are created in the cured epoxy.

Only apply cured epoxy to desired areas of phone case:

1. Using a foam brush, apply cured epoxy to the back of the carbon fiber case.
   
   • Dabbing the epoxy into the carbon fiber seems to be the best method of application.
   • Avoid putting too much epoxy to the phone case. However, be sure to fully impregnate the fibers with epoxy to ensure no dry spots result during the vacuum bagging process.
2. Carefully pick up the case by the edges and apply more epoxy to the front side of the carbon fiber case.
   • Brush around the edges of the case.
   • Make sure the corners of the case are completely covered with cured epoxy.
   • Avoid applying epoxy to the tape holding down the carbon fiber and the center opening exposing the plaster.

Fully work cured epoxy into fibers for best results.

1. Obtain a vacuum bag and cut a small hole in the center of one side.
   • The hole should be large enough to insert the vacuum valve.
2. Insert the vacuum valve by locking it together from each side of the hole.
3. Apply a strip two sided adhesive tape to one side of the bag.
   • Peel one side of the adhesive tape and place inside the edge of the bag with roughly 2" of overlap on each side. Remove the other side of the tape and seal the side of the bag shut.
   • Firmly press down and stretch out bag edges in order to ensure a tight seal to the adhesive and to avoid any leaks.
4. Insert phone case(s) into the bag.
   • If there is more than one case, be sure to separate the cases by roughly 1" for best results.
   • The corners and edges of the bags are the best locations for optimal results.
5. Apply a second strip of two sided adhesive tape to the open side of the bag and seal completely shut.
   • Use the same method described above.
   • Make sure no epoxy is on the edge of the bag where the adhesive goes, otherwise the adhesive will not seal properly and the vacuum will not effectively work.
6. Gently press down on phone case(s) while in bag and smooth out any air bubbles or wrinkles between the bag and the case(s).
7. Attach the hose to the vacuum valve nozzle.
   
   • Press down firmly so leaking cannot occur.
8. Turn on vacuum pump.
   • Listen for any signs of leaking. If areas of leaking are presents, firmly press down on the area and smooth out the contact point to provide for a better seal.
   • Let the vacuum run for at least 1-2 hours or until epoxy sets.

After the vacuum bagging process is completely finish and the vacuum pump is turned off:

1. Cut open vacuum bag and retrieve phone case.
   • Phone case should be hard and relatively shiny in appearance.
2. Lay down a sizable sheet of wax paper on your workspace and place phone in center.
3. Remove any tape from phone case. With a hammer, begin chiseling out the plaster from the small opening left in the center of the case with.
   • This process is very messy.
   • Avoid letting plaster powder get settle into the cured fibers of the phone case. If this happens, gently whip down with a damp paper towel.
   • Use tweezers to remove plaster in the corners and edges of case.
4. After the plaster is completely removed from the inside of the case, begin dremeling.
   • Cut edges of phone case to desired points and cut out any holes. Cutting and sanding bits should be used during this step.
5. If desired, use the buffing bit on the dremel to polish out any undesirable areas of set epoxy.
   • Be careful not to buff too much. Excess buffing can completely remove epoxy in areas and expose raw carbon fiber.
   • Dremeling creates a lot of excess dust and debri. It is recommended to wear a dust mask during this step.
6. For a shinier finish, mix and apply an additional layer of cured epoxy to the case. Let dry for at least to hours.

Congratulations! Your phone case is complete and ready to be used. Enjoy!