This Instructable will walk you through the steps needed to make a neat phone case at home using just a few materials. Let's get started!

Step 1: Gather Materials and Personal Protective Equipment

This process involves using a number of hazardous materials. The epoxy used can be harmful if it comes in contact with skin, eyes, or any orifices. Additionally, hardened carbon fibers in later steps can cause skin irritation.

Materials

Plaster Mold

Phone case
Plaster of Paris
Glad Press'n Seal wrap
16oz plastic cups
3oz dixie cups
Cold water
Paper towels
Saran Wrap

Carbon Fiber Case

Plaster phone mold
0.5 square feet Carbon Fiber Sheet
Epoxy Resin and Hardener
16oz plastic cup
3oz dixie cups
Popsicle Sticks
Wax Paper
Foam brush
Masking Tape
Vacuum bag
Vacuum Adhesive strips
Vacuum nozzle and hose
Vacuum pump

Personal Protective Equipment

Apron or lab coat
Nitrile gloves
Dust mask

Note: It is important to use nitrile gloves specifically, as they protect skin against the chemicals in the epoxy. The Material Data Safety Sheet for the epoxy can be found here: https://stars.berkeley.edu/assets/files/epoxy105_MSDS.pdf

Step 2: Create a Workspace

You'll want to clear a large, flat desk space and cover it with Saran Wrap. This will prevent any materials from spilling and making a mess. This would be a good time to put on the personal protective equipment.

Step 3: Prepare Phone Case

Start with a phone case that fits your phone. Place it with the hollow side up on the table and line it with the press and seal wrap. This will protect it from getting messy when making the mold with plaster of Paris.

Pay special attention to the corners and holes in the case. The more tightly the case is lined and the less wrinkles there are, the better the mold and the case will turn out. Push the wrap through the holes an extra bit so that later it will be apparent where the holes in the case need to be carved out.

Step 4: Make the Plaster

Use the Dixie cup to measure out approximately 3 oz of plaster and put it in the larger plastic cup. Slowly add cold water and mix with the popsicle stick. The consistency should be somewhat thick but still able to be poured. It's good to aim for something in between pancake batter and cake batter. Try to make sure that there are no lumps.

Step 5: Make the Mold

Now that the phone case is lined and the plaster is mixed, it's time to make the mold. Carefully pour the plaster into the lined phone case, filling until the plaster is level with the top of the case.

Let the plaster dry for 24 hours.

Step 6: Remove Mold From Case

Once the plaster has dried, remove it from the phone case. It easiest to start at the corners and then get the edges off. Be extra cautious not to break the mold during this stage, as that will set you back 24 hours. Once the mold is out, sand down any uneven spots or corners using the popsicle stick.

Step 7: Cut the Carbon Fiber

Lay the phone mold on the square of woven carbon fiber and measure out an extra inch around the perimeter. Put down tape around this perimeter and then cut out the rectangle, cutting in the middle of the tape strips. This keeps the carbon fiber from fraying where the cut is made.

Step 8: Wrap Phone Mold in Wax Paper

Cut out wax paper with same dimensions as carbon fiber. Wrap this around the phone mold. This should leave some of the mold exposed. Make sure that the exposed side isn't the one with the case imprint. Tape down the edges to secure the wax paper to the mold.

Step 9: Wrap the Carbon Fiber Around the Mold

Wrap the carbon fiber around the mold using the same method as for the wax paper. Try to keep the corners from getting too bulky or else the case won't look right. Once the carbon fiber is formed into the shape that you'd like the case to be, tape down the edges.

Step 10: Prepare the Epoxy

Measure out epoxy resin and hardener in separate cups in proportions according to manufacturer's instructions. Make a total of approximately 50-60 mL. Pour the resin into the large plastic cup, and then slowly mix in the hardener. Mix slowly to avoid creating bubbles in the epoxy.

Step 11: Apply Epoxy

Make sure to have the nitrile gloves on for this step. Using the foam brush, apply the epoxy to the carbon fiber on the phone mold. The more you can impregnate the fiber weave with the epoxy, the better the final product will turn out.

It's best to start with the tape side up, but make sure not to get any epoxy on the tape or the mold will be very difficult to remove later. After you have completed the first side, flip the case over and set it on something disposable that only contacts the exposed, non-epoxied part. Then saturate the back side of the case with epoxy.

Note: unused epoxy should be left out to cure before being disposed of. Uncured epoxy is hazardous and can pose health risks to anyone who comes in contact with it.

Step 12: Preparing Vacuum Bag

Cut a sheet out from the vacuum bag roll that is large enough to accommodate the phone case and an additional extra 2-3 square inches. Seal one side of the bag with vacuum bag sealant while leaving the other side open. Through the open side, place the phone case exposed-side-down and vacuum nozzle ensemble in the bag. Place the phone as far away in the bag as possible from the vacuum nozzle. Take care not to get any epoxy on the bag where it will be sealed as this will compromise the vacuum. Seal the other side of the bag once all components are inside by pressing the vacuum sealant in between the two layers of the vacuum bag sheet.

Step 13: Turn on Vacuum

Attach vacuum hose to nozzle, using more sealant to ensure a tight fit. Plug the vacuum pump in and then turn the vacuum on, inspecting the system for any leaks. Once the vacuum has sucked the air out of the bag, smooth out any bubbles or uneven areas that appear on the surface of the phone case. Run the vacuum for the same amount of time that your epoxy takes to cure.

Step 14: Removing Plaster

Once the epoxy has cured, removed the case from the bag. Make sure to have the dust mask on for the following steps. Use a hammer to crack the plaster mold on the exposed side so that the plaster can be removed. Don't be afraid to use some force; the phone case should be very sturdy at this point. Use a screwdriver to remove any hard-to-reach plaster or wax paper.

Step 15: Carving Out Final Dimensions

Use a dremel tool to cut out the final dimensions of the phone case. Use the cutting attachment to make large cuts, and the drilling and polishing attachments to make holes for buttons and smooth out and areas, respectively.

Note: Cutting away from the body is generally a safe practice and can prevent injury.

Step 16: Gloss Coat

To make the case look nice, one more layer of epoxy should be applied. Mix the epoxy as per the instructions in earlier steps, and then cover the whole case one more time to make the finish shiny and nice. Once again, let cure according to manufacturer's instructions.