How to Make Carbon Fiber Prepreg: Simple Methods and Tips

How to Make Carbon Fiber Prepreg: Simple and Effective Process

1. Necessary Materials

• Carbon fiber fabric: any type (1K, 3K, 12K, plain or twill weave).

• Epoxy system: includes low-viscosity epoxy resin and hardener, such as E51 or E20 with hardener T31 (or 650).

• Tools: mixing container, electronic scales, spatula, roller, vacuum bag (optional).

• Protective gear: gloves, mask, goggles.

• Auxiliary materials: separator film, perforated film, absorbent felt (optional).

2. Simple Methods of Making Prepreg

Method A: Manual Resin Application (The Simplest)

• Mixing the Resin - Mix epoxy resin and hardener in the required ratio (usually 100:25) and stir thoroughly.

• Preparing the Fabric - Lay the carbon fiber fabric on a smooth surface.

• Applying the Resin - Use a roller or spatula to apply a thin layer of resin to the fabric, flip it over, and apply a layer to the other side.

• Removing Excess Resin - Gently remove excess resin with a spatula, leaving the surface "wet but not flowing."

• Vacuuming (optional) - If you have a vacuum pump, package the material in a vacuum bag for a few minutes.

• Storage at Low Temperature - Place the fabric in an airtight bag and store it in the fridge (0-5°C). It can be used immediately or after a few days.

Method B: Between Two Films

• Place the fabric between two layers of polyethylene film.

• Pour the resin from one end and roll with a rubber roller for even distribution.

• Pack and store in the fridge.

Method C: Semi-Polymerization (For 3-5 Days of Storage)

• After impregnation, place the fabric in an oven at 40-50°C for 5-10 minutes.

• Once the surface becomes slightly tacky, but the resin is not flowing, remove it and seal it airtight.

• Store in the fridge.

3. Curing

• At Room Temperature: 25°C × 24 hours.

• With Heat: 80°C × 4 hours or 120°C × 2 hours.

4. Important Tips

• Follow the exact proportions of resin and hardener.

• Avoid bubbles during mixing.

• Do not apply too much resin, the fabric should be impregnated but not dripping.

• Store the prepreg in cold conditions.

• Manual methods are suitable for small batches and may not ensure stable fiber content.