How to Build With Fiberglass Resin

Fiberglass is an extraordinarily flexible material for building all kinds of shapes and structures.

Fiberglass can be used to fashioned countless curvilinear shapes, such as canoe hulls.Fiberglass can be used to fashioned countless curvilinear shapes, such as canoe hulls.
The basic principal is that a resin-saturated cloth and fiberglass mat are laid over a wooden frame, and when the resin hardens the resultant shell is strong but relatively lightweight. Whether you're building a fiberglass dog house or a subwoofer enclosure, the basic procedure for creating a fiberglass structure is pretty much the same.

Construct a frame from medium density fiberboard (MDF). The frame needs only to support the outside edges of the final shape, and only needs to be strong enough to support the initial layer of fleece soaked with resin.

Stretch a layer of fleece over the frame and staple it into place. If possible, drive the staples in portions of the frame that will not be exposed in the final structure.

Mix the two-part resin according to the manufacturer's instructions. Measure the proper amount of resin and hardener by weight with a digital scale. Mix the two components together thoroughly with a mixing stick.

Paint the resin onto the fleece until it is completely saturated with resin. Allow it to completely harden, according to the manufacturer's directions.

Apply fiberglass batting to the hardened fleece. Mix a new batch of resin and paint it onto the surface of the hardened fleece. Press fiberglass batting into it. Apply another coat of resin over the fiberglass until it is saturated. Allow it to completely harden. Use the same procedure to apply additional layers of batting until the structure is the thickness and harness you want.

Apply fiberglass-based body filler, such as Duraglass, if you wish to have a smoother surface. Mix the two parts of the filler according to the manufacturer's instructions. Apply the filler to the surface of the fiberglass with a putty knife. Allow it to harden. Sand the body filler smooth with a disc or flap-wheel sander.

Things You Will Need

  • Medium density fiberboard
  • Table saw
  • Hammer
  • Nails
  • Lightweight fleece
  • Staple gun with staples
  • Two-part epoxy resin
  • Disposable plastic cups
  • Digital scale
  • Plastic mixing bucket
  • Mixing sticks
  • Disposable gloves
  • Resin-compatible paint brushes
  • Fiberglass batting
  • Duraglass body filler (optional)
  • Plastic putty knife or spatula
  • Disc or flap-wheel sander


  • The final coat may be painted with a fiberglass-compatible spray paint. Another alternative is to add pigment to the resin or body filler itself before applying it to the structure.
  • Depending on the nature of the structure, the reinforcing batting may be applied under, rather than on top of, the fleece layer.


  • Liquid epoxy resin emits harmful vapors. Always apply it in an area with sufficient ventilation.
  • Do not allow liquid epoxy to come in contact with skin. Always wear disposable gloves when working with it.
  • Once the two parts of the epoxy are mixed, it will begin to set. How quickly it hardens depend on the type of epoxy used. If you're building a structure that may take more than 20 minutes to coat, make sure you use an epoxy product with an adequate working time, or "pot life."

About the Author

Scott Knickelbine began writing professionally in 1977. He is the author of 34 books and his work has appeared in hundreds of publications, including "The New York Times," "The Milwaukee Sentinel," "Architecture" and "Video Times." He has written in the fields of education, health, electronics, architecture and construction. Knickelbine received a Bachelor of Arts cum laude in journalism from the University of Minnesota.