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.
