Fibre Glast Shopping Cart Image
McAfee Secure sites help keep you safe from identity theft, credit card fraud, spyware, spam, viruses and online scams
Products Category Text

Polyester Resins

Polyester Resins are the most widely used resins in the composites industry. Polyester Resins are less expensive, offer some corrosion resistance, and are more forgiving than epoxies. The majority of all fiberglass parts are constructed using Polyester Resins because they are easy to use, fast curing, and tolerant of temperature and catalyst extremes.

Scroll down for more general polyester resin information. To learn more about specific products and pricing, click on an image below.

Sort Products
Products per Page

Polyester Molding Resin
Wax Free, General Purpose Resin

#77 Molding Resin is ideal 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 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 Styrene Wax to the resin, or spraying the applied resin with a coat of 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.  
Isophthalic Polyester Resin
Durable Resin for Stable Fabrications

#90 Isopthalic Polyester is perfect for making dimensionally stable polyester molds, fabrication of corrosive service parts, and as a durable repair material for tank linings. This Iso polyester resin offers fast wet-out in spray or hand laminates. When spraying, we recommend using a 1/8" nozzle. The 225 degree F service temperature resists exotherm and post cure problems. #90 has better strength properties than a general purpose polyester resin, which allow it to be used in more demanding applications.
Properly fabricated parts may be used in food contact, electrical and military applications.
#90 Isopthalic Polyester resin is formulated for 1.25% MEKP catalyzation. This resin can be purchased alone or as part of a Resin and Hardener Kit.

90/69-F kit contains (1) QUART RESIN, (1) 69-A.
90/69-A kit contains (1) GAL RESIN, (2) 69-A.
90/69-AK kit contains (4) GAL RESIN, (8) 69-A.  
MEKP Hardener
Industry Standard Catalyst

Methyl Ethyl Ketone Peroxide, or MEKP, is required with all polyester resins, gel coats and vinyl ester resin. It is required in different concentrations as defined for each resin product.

Each resin product is available as a kit with the correct amount of hardener. However, hardener may be purchased individually as shown here.
Styrene Wax
Get a Complete Cure

Add Styrene Wax to non-waxed polyester resin and gel coat to prevent the prolonged tackiness associated with thin sections of polyesters in your composite.

This Styrene Wax is a 5% paraffin dissolved in styrene. When paraffin is added to resin, the wax will rise to the surface and protect the curing resin from the inhibiting action of the air. Once the resin is allowed to fully cure, it must be sanded off prior to any additional applications. Any paraffin on the surface will prevent adhesion of further coats.

Mix #71 at 5% for thin coatings—approximately one to two tablespoons for every pint of resin. When performing repairs below the water line, use with #1040 Hi-Gloss Additive. 
Polyester Fairing Compound
Creamy Non-Sag Fairing Compound

Polyester Fairing Compound is a fibrous filler for structural repairs, bonding, and part fabrication. This smooth, white, thixotropic paste system is great for rebuilding broken, void, or damaged areas in composites and other materials. Unlike other body fillers, #4100 Polyester Fairing Compound exhibits low shrinkage, high impact strength, and excellent temperature and chemical resistance. It also has great heat and cold resistance and no bleed out. It is easy to mix, has excellent adhesive qualities, low moisture absorption, and can be applied in varying degrees of thickness. Use this versatile Polyester Fairing Compound to permanently repair damage on a boat or to smooth and shape the external surface of a part.

Using this fairing compound is simple. After prepping the surface mix #4100 with a BPO Hardener. Our kits ship with white BPO hardener, however you may want to purchase either Red or Black as an off-color mix indicator. When mixing is finished, the fiber-filled paste can be applied and smoothed with a squeegee or spreader. If your application requires a perfectly smooth cosmetic surface, after using #4100 Polyester Fairing Compound, we recommend using our #4116 Lightweight Polyester Cosmetic Filler.

#4100 is Compatible with Epoxy Resin, Polyester Resin, and Vinyl Ester Resin.
Requires BPO Hardener - 100R:2H (parts by weight).

To get the best mechanical bond, it is recommended to use #4100 Polyester Fairing Compound on rough or fibrous surfaces. Bonding applications include: composite repair, marine fabrication, FRP composites to FRP, metal inserts to fiberglass, metal to concrete, detail blocks to FRP, wood to wood bonding, and metal to metal bonding.

4100/264-A Kit contains 1 Quart Polyester Fairing Compound & 1 oz. tube of White BPO Hardener.
4100/264-B Kit contains ... 
Carvable Low Density Polyester Filler
Easy to Carve, Shape and Sand

#4115 Carvable Low Density Polyester Filler is a brown, creamy, non-sag paste used to fill or repair damaged areas in composite materials and wood. It has a normal working time and a quick cure and finishing schedule allowing for incredibly fast repairs. Requires BPO Hardener – 100R:2H (parts by weight).
This filler mixes easily and can be sanded, scraped, machined, or carved. When fully cured this low density filler is semi-rigid, meaning it won't dull or damage your tools. It can be sanded to a fine feathered edge.

To use this filling compound, prep the surface and mix #4115 with a BPO Hardener. Our kits ship with white BPO hardener, which will act as a mix indicator with the brown paste. In order to more closely match a given wood grain, you want to purchase either Red or Black. When mixing is finished, the us a squeegee or spreader to apply and smooth. #4115 cures to a 60 Shore D hardness, making it similar to most hardwoods. It can be used to repair both hard and soft woods, or with composite materials. Typical applications include: wood staircases, furniture repair, composite fillets and radius areas, master models, pattern/fixtures, and for repairs to tool boards.

4115/264-A Kit contains 1 Quart Carvable Low Density Polyester Filler & 1 oz. tube of White BPO Hardener.
  • Resin Color – BrownWhite BPO Hardener offers a standard wood finish, Red BPO Hardener offers a Cherry/Cedar Finish, Black BPO Hardener offers a Wenge/Black Walnut Finish
  • Working Time (100 gram mass) – 4-6 minutes
  • Finish Schedule (100 gram mass) – 15-20 minutes
  • Cured Hardness – 60 Shore D
Lightweight Polyester Cosmetic Filler
High Quality No-Shrink Surface Filler

Lightweight Polyester Cosmetic Filler is a versatile, two-part, creamy paste designed to fill, seal, repair, and finish surface damage on composite materials. This filler demonstrates excellent physical and cosmetic properties. When applied, this thixotropic paste quickly forms an exceptionally rigid and strong surface which can easily be sanded to a feather edge. #4116 Lightweight Polyester Cosmetic Filler will not shrink, sag, or pin-hole after curing, and it can accept virtually any paint or finish without any special surface preparation.
Requires BPO Hardener – 100R:2H (parts by weight).

#4116 Lightweight Polyester Cosmetic Filler works extremely well with #4100 Polyester Fairing Compound. For applications that require a structural repair, use #4100 Polyester Fairing Compound, a fibrous filler, to rebuild broken, void, or damaged areas, then apply this #4116 Lightweight Polyester Cosmetic Filler over the repair to achieve a smooth, cosmetic surface.

Apply catalyzed #4116 Lightweight Polyester Cosmetic Filler with a spatula or putty knife. After 15-20 minutes, this filler may be sanded to final finish. Typical applications of #4116 Lightweight Polyester Cosmetic Filler include: bass boat hull repair, composites repairs, filling composites surface porosity, vacuum mold repair, tub & bath repairs, automotive finishing, urethane mold repair, crack, dent, and crevice repair, urethane part repair, renewing worn surfaces, and much more. When cured, this filler adheres to fiberglass, SMC, RIM, BMC, plaster, graphite, KEVLAR, Steel, Iron, and Copper.

4116/264-A Kit contains 1 Quart Lightweight Polyester Cosmetic Filler & 1 oz. tube of White BPO Hardener.
  • Resin Color – White
  • Working Time (100 gram mass) – 5 ± 1 minutes
  • Finish Schedule (100 gram mass) &ndash... 
BPO Hardener
Cream Hardeners

White BPO, Red BPO, and Black BPO are cream hardeners for use with the following Fibre Glast polyester systems:
  • #4100 Polyester Fairing Compound
  • #4115 Carvable Low Density Polyester Filler
  • #4116 Lightweight Polyester Cosmetic Filler
Our kits ship with white hardener, but you can select either Red or Black for use as a mix indicator. All hardeners are easy to use and offer effective rapid reactions.
  • Available in 2 sizes - 1 oz. and 4 oz.
  • ul>  

#77 Polyester Molding Resin is a wax-free, general purpose resin. This resin is a great choice for building low-cost molds, or for general part fabrication. #90 Isophthalic Polyester Resin is a durable, dimensionally stable, corrosion resistant resin. The 225°F service temperature and low shrinkage properties of this resin are ideal for making dimensionally stable molds or extremely durable parts.

Want to learn more about Polyester Resins? Fibre Glast has a free Learning Center with helpful white papers like: About Resins, Mold Construction, Molding Fiberglass, and Fundamentals of Fiberglass. You can also contrast Polyester Resin with Epoxy Resin and Vinyl Ester Resin in the Fibre Glast Blog article: Choosing the Right Resin.

You can place your order right her on our website or, if you have any questions, call 1.800.838.8984 | 8:00am - 8:00pm EST Mon-Fri.

Fibre Glast Blog  Materials Calculator  Shipping Information  ISO Certification
Fibre Glast Development Corp.
385 Carr Drive
Brookville, OH 45309
Phone: 800-838-8984
Fax: 937-833-6555

Visa, MasterCard, Discover, American Express, & Purchase Orders Gladly Accepted