Details
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.

Data Sheets
#77 Polyester Molding Resin - Product Data Sheet
#77 Polyester Molding Resin - Safety Data Sheet
Shipping
Polyester Molding Resin quart (#77-F) and gallon (#77-A) units and kits can be shipped via standard ground service without hazard charges within the 48 contiguous United States. 5-gallon quantity (#77-B) is considered hazardous (flammable) and will be subject to a hazard charge if shipped by standard ground. All sizes of #77 (quart, gallon, and 5-gallon) will be subject to a hazard charge if shipped by air. Please see our Hazardous Shipping Chart for more information about hazard fees. We will consolidate items whenever possible to minimize these fees.Sizes
Polyester Molding Resin This resin is available in a variety of sizes that include: One quart (#77-F) One gallon (#77-A) A five-gallon pail (#77-B) One drum (#77-DRUM) *Quantity discounts are available on the five-gallon pail only, when four or more units are ordered at one time. This resin can be purchased as part of a kit that includes MEKP catalyst. You should purchase the kit unless you already have hardener in your workshop. The kits include: One quart of resin, with one 1 oz. bottle of hardener (#77/69-F) One gallon of resin, with two 1 oz. bottles of hardener (#77/69-A) One case of four gallons, with eight 1 oz. bottles of hardener (#77/69-AK)Reviews
Product Review
Jan 17, 2023 | By Patrick Murray
Fiberglast 77
Apr 23, 2022 | By Doug Yasner
Good quality but container damage
Mar 7, 2022 | By Alex Christie
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.