Fibreglass consists of a combination of resin and reinforcement. The resin acts as a sealant and cement and the reinforcement is the material giving strength and structure. According to the "Fiberglass Site," If mixed and applied properly, fibreglass can be stronger and lighter than metal. Applying fibreglass properly not only requires the right application and combination of the two materials, but also proper preparation of the fibreglass resin. Fibreglass resin consists of a resin and a hardener which should be mixed at the proper ratio.
Measure how much resin you will need before mixing the fibreglass resin by considering the size of the job and the ratio for the resin mixture. The exact ratio of resin and hardener depends on the kind of resin you are using as well as the temperature in which you are working and how quickly you would like it to dry. Hot weather requires less hardener to dry, and a larger job requires more time finish before the resin cures. Consult the mixing instructions and make adjustments according to these factors.
Mark the measurements in your bucket before mixing or by using 2 measuring cups to measure how much resin and hardener to use. Epoxy hardeners for fibreglass come in slow, medium and fast curing varieties. Consult the instructions for the ratio needed. The ratio of resin to hardener is usually between 2 parts resin to 1 part hardener to 4 parts resin to 1 part hardener (Ibid).
Measure and pour the resin into the bucket, and then measure and pour the hardener into the bucket. Mix the two together using your wooden stir stick. The side of the bucket will begin to heat up as the two chemicals react.
Epoxy and other fibreglass resins are harmful to your skin, lungs and eyes. Wear protective goggles, a face mask and gloves when mixing the resin.