Polyester Molding Resin

For orders placed before 2:30PM EST
WARNING: This product can expose you to chemicals including Benzene, Catechol, and Styrene which are known to the State of California to cause cancer and Toluene, Methanol, and Benzene which are known to the State of California to cause birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov
General Purpose Resin for Part/Mold Fabrication
#77 Molding Resin is ideal as a orthophthalic fiberglass resin for general purpose part fabrication and for building low cost molds. It features an internal thickening agent which results in a high thixotropic index. This prevents drainage when applied to vertical surfaces, yet this polyester resin retains the low viscosity required for rapid wet out. As a first quality resin, the color, consistency, and properties of this resin will not vary from batch to batch. #77 Orthophthalic Polyester Resin is easy to work with and since it is wax free, you don't have to sand between coats.
As a wax-free resin, air must be inhibited during the cure cycle for repairs, single or thin layer applications. To inhibit air we recommend either adding #71 Styrene Wax to the resin, or spraying the applied resin with a coat of #13 PVA. If air isn't inhibited, the resin may not properly cure and remain tacky. For thick or multiple layer applications the heat generated during the exotherm will allow the resin to cure fully.
#77 Polyester resin is formulated for 1.25% MEKP catalyzation. This resin can be purchased alone or as part of a Resin and Hardener Kit.
#77/69-F kit contains (1) QUART RESIN, (1) #69-A.
#77/69-A kit contains (1) GAL RESIN, (2) #69-A.
#77/69-AK kit contains (4) GAL RESIN, (8) #69-A.
For a premium grade Polyester Resin, see our #90 Isophthalic Polyester Resin.















The Gallon cans are challenging to pour from cleanly so do recommend the resin pump if doing small batches. Overall a great resin to learn with since it is the lesser expensive option but still very effective.


































