Making a Mold

  • Ensure clean, smooth surface

  • 5 coats of mold release wax

  • 5 coats PVA

  • Tooling gelcoat 25-35mm

    • 5 coats with a brush

      • Must be tacky when subsequent layers applied

      • Short pot life, so ensure that multiple coats are pre measured

  • Slurry paste in grooves

  • Precut material; mold should be at least 5x thickness of part being made

  • Coat surface with tooling resin

  • Veil mat (prevents print through); thin with continuous fibers. this prevent the short fibers from poking through the gelcoat

    • Completely wet it out

  • Medium weight cut strand mat

    • Lay down

    • Wet out

    • Compact with rollers

  • Woven Cloth: adds bi-directional stability

    • Lay down

    • Wet out

    • Requires less resin that cut strand

  • Bulker Mat: non-woven, high-density

    • Lay down and wet out

  • Stiffeners

  • Medium weight cut strand mat

  • Woven cloth

G100 Gelcoat Gun

  • Good video overview here

  • He runs at 100psi



  • Pot life is calculated at ambient temperature of 70 degrees

  • Cure time is inversely related to temperature

  • Weaves

    • Plain

    • Twill; diagonal herring bone pattern (common for carbon finished carbon fiber parts)

      • 2x2 and 4x4 (looser) are common

  • Satin; very flexible, not as attractive

  • Toe size; number of strands x number of fibers per strand

  • Drapeability; weave + toe

  • Zilon; super strength, high temp

  • PVA

    • Spray: going to start with 30 psi

    • Spray for 1 second 12" from surface; spray fan should be 12" wide, uniform, wet with no drips or sagging

    • Spray at 1-2 feet per second perpendicular to the surface