Fiberglassing for Beginners: How to Mix Polyester Resin with Catalyst

In this video we explain how to add catalyst to polyester resin for fiberglass repair or building new parts. Polyester resins are commonly used with fiberglass and sometime mistakenly called fiberglass resin. The information in this video may also apply to vinylester resin systems.
To clear up what could perhaps be a little confusing, historically the curing agent for the resin has been called catalyst and often still is, however in recent years there has been a push to call it an initiator as it does not behave as a true catalyst. In chemistry a true catalyst starts a reaction but is not consumed or changed in the reaction. In this case the curing agent is consumed and a more accurate description of it is as an initiator. Both terms are used in the video as the term catalyst is recognized as industry jargon. The term initiator would be more correct.
Epoxy resins use a completely different chemistry and have different mixing requirements, our video on mixing epoxy is here: • Epoxy for Beginners: M...
Some general guide lines:
For best results use measuring equipment, i.e. graduated mixing buckets for the resin and a pipette, graduated measuring cup (1oz with smaller graduations), or a catalyst dispenser for the initiator or catalyst.
Polyester Resins can be found here fiberglasssupp...
MEKP Initiator (catalyst) can be found here fiberglasssupp...
Mixing supplies can be found here fiberglasssupp...
Polyester resin catalyst is an oxidizer and can be dangerous. Please refer to the SDS sheet for safety information.
Learning how to mix polyester resin is an important step in ensuring a positive outcome on your part or project. Catalyst rates can be changed to match the size batch, temperature, and part conditions that you are working with, however catalyzing too low or too high can have negative impacts on your resin curing. This tutorial is meant as a starting point and not a comprehensive guide to working with polyester resin so if you need more information please contact us through our website fiberglasssupp...