How to Use the Fiberglass Spray Lay-up Process

Written by alex zang
  • Share
  • Tweet
  • Share
  • Email

When building something using fibreglass, you can apply the fibreglass in two different ways. Many people are familiar with the hand layup process, in which you put a piece of fibreglass over a mould, then use a paint brush to cover it with resin. The second, less commonly known, option is spray layup. In this method of construction, you use a spray gun that mixes the resin and the fibreglass to cover a mould. This is more commonly used in larger moulds where precision doesn't matter.

Skill level:

Things you need

  • Mold release agent
  • Sprayer
  • Paint brush
  • Gel coat
  • Felt roller
  • Barrier coat
  • Epoxy
  • Drill mixer
  • Resin mixture
  • Glass fibre rovings
  • Fibreglass sprayer

Show MoreHide


  1. 1

    Apply a mould release agent to the mould. This can be done by using a sprayer or a brush. Apply two to four coats of release agent.

  2. 2

    Apply a gel coat to the surface of the mould. Again, this can be sprayed on or brushed on. Either way, it's important to have an even finish. Give the gel coat four hours to harden before moving on to the next step.

  3. 3

    Apply a barrier coat. Mix the epoxy with a drill mixer, let it sit for 15 minutes, then use a felt roller to apply the barrier coat. Let the barrier coat sit for three hours, then apply a second coat. The barrier coat protects against water damage.

  4. 4

    Mix the resin according to manufacturer's instructions. Pour it into the holding tank of the fibreglass sprayer. Insert the glass fibre rovings into their designated area of the spray gun.

  5. 5

    Spray the mould. The resin will mix with the chopped fibreglass as it hits the mould. Move the spray gun in a predetermined pattern to make sure you get an even coat.

  6. 6

    Use a roller on the mould once the mixture has been sprayed. This ensures the resin and the fibreglass bits are stuck together and that entrapped air is removed.

  7. 7

    Allow the fibreglass to cure for a few hours. Repeat steps 5 and 6. Allow the glass to cure again.

  8. 8

    Remove the fibreglass from the mould. If you applied the mould release agent properly, this should be relatively easy.

Tips and warnings

  • Always wear safety goggles and a ventilation mask when working with fibreglass.

Don't Miss

  • All types
  • Articles
  • Slideshows
  • Videos
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the site, you consent to the use of cookies. For more information, please see our Cookie policy.