How to Spray Fiberglass

Fiberglass is a strong and durable material used for the construction of anything from surfboards to industrial tanks. Fiberglass consists of layers of reinforced fiberglass material that is saturated with catalyzed resin. The overall strength and thickness of the fiberglass depends on the amount of layers used. When constructing big parts, the fiberglass is sprayed on using a resin gun. The resin guns have a container of catalyst and a drum of resin that is all hooked into a spray gun. The catalyst and resin is released from the tip of the spray gun simultaneously causing it to mix in the air.

Step 1

Fill the resin container on the resin gun with the specific type of fiberglass resin needed for the job. Mix the resin with a 4-foot drill mixing attachment and an electric drill.

Step 2

Put on a pair of rubber gloves and fill the catalyst container on the resin gun following the directions in the manual. Close the lid and secure it.

Step 3

Put on a respirator and connect the resin gun to an air hose that is attached to an air compressor. Make sure all the air pressure gauges on the resin gun are at the levels the manual recommends. Spray the gun into a bucket to make sure the catalyst is coming out of the tip and the gun is spraying correctly.

Step 4

Spray the entire surface of the part you are applying fiberglass to in a heavy mist. Apply the first complete layer of fiberglass material to the part and saturate it with resin using the spray gun. Evenly spread the resin onto the material using a felt roller. When the entire layer of material is saturated with resin remove any air bubbles from underneath the material using and air roller. Repeat this process until all the layers of material are applied to the part. Let the fiberglass harden.

Step 5

Clean the tip of the resin gun thoroughly with acetone and a paint brush immediately after you are done using it. If the fiberglass hardens in the tip it will cause damage and possibly ruin it.


  • Always wear a respirator and skin protection when working with fiberglass materials.

About the Author

Jason Kurz has been a published writer for eHow.com and Trails.com for less than a year now. Kurz attended Kent State University of Ohio for Computer Aided Design.