Polyester Molding Resin

4.7 star rating

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  • Item
  • Description
  • Price
  • Qty
  • 77/69-F
  • 77/69-F
    Quart w/ hardener
  • $49.95
  • 77/69-A
  • 77/69-A
    Gallon w/ hardener
  • $99.95
  • 77/69-AK
  • 77/69-AK
    Case (4 Gallons w/ hardener)
  • $364.95

  • 77-F
  • 77-F
    Quart (2 lbs)
  • $44.95
  • 77-A
  • 77-A
    Gallon (9 lbs)
  • $94.95
  • 77-B
  • 77-B
    5 Gallon Pail (40 lbs)

    Quantity Discounts

  • $349.95


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.

warning WARNING: Cancer and Reproductive Harm. For more information go to www.P65Warnings.ca.gov


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.


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)


4.7 star rating

Product Review

Jan 17, 2023  |  By Patrick Murray

We ordered two gallons of resin 77-A. When we unpacked them, we found we found one of them had the corner crushed. It looked like it must have been dropped from a great height. Luckly it was not leaking and was useable. We were very surprised as the box did not show any sign of damage. The product was/is great as usual.

Fiberglast 77

Apr 23, 2022  |  By Doug Yasner

Your 77 is the best resin I've used,and I've been doing this for 40 years.....Thank You for a Great Product!!

Good quality but container damage

Mar 7, 2022  |  By Alex Christie

I received a large order of 12 gallons of this product. Product itself is great and would recommend. Reason for the lower review was because it was shipped in a regular cardboard box with nothing on the bottom. All 4 cans were severely damaged on the bottom from transport. One looked to be leaking slightly so I transferred to another container. Packaging material on the bottom of box may be helpful for future orders.
Quality Products
Feb 12, 2022  |  By RONALD F FENNING
I will be replacing the deck core this spring and the value of buying in a 5 gallon container was the correct move.

Good product as usual
Nov 26, 2020  |  By Patrick Murray
Good product as usual

Polyester Molding Resin
Jul 16, 2019  |  By Douglass Schaeffer
This material was ordered for a future project. It will not be used for several weeks. I have used this resin before and my rating will reflect that experience!

Loved the product
Jan 5, 2019  |  By Krystal Gorman
I bought the smaller quantity to try out this product. I loved it so much that I purchased the Gallon. It works splendidly and I plan on working more with this company for future projects.

Easy to work with but fast in warm climates
Jul 16, 2017  |  By Joe Fraser
This is an easy inexpensive resin to work with. It is fast even minimally catalyzed in warmer climates. You will need to work in much smaller batches or get an extra set of hands to help larger or complex projects.
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.

dented gallon container
Mar 2, 2017  |  By Nick
Resin is excellent - big fan of all Fiberglast's products. My only concern is the metal gallon container came seriously dented at the bottom - appears that the package has been roughly handled during shipping at some stage compressing the bottom of the metal container, glad it didn't puncture. 4 stars, will be 5 when container arrives undented.

Great Resin
Aug 29, 2016  |  By Ben Phillips
After using 5 gallons of another brand, we were very impressed with yours. All around just a better resin.

May 12, 2016  |  By Darrell Dishman

Great but...
May 1, 2016  |  By Taylor Goble
The product defiantly does its job but the hardener needs to come in a drop bottle for control

got it right
Jan 12, 2016  |  By Willem van Dijk
Was sent the wrong fiberglass for my particular job. Called and talked to a rep. that was able to straighten everything out. Very helpful and professional.

Polyester resin
May 5, 2015  |  By Douglass S
I am curious why you discontinued your #83 polyester resin with wax?

High quality
Mar 19, 2015  |  By Terry R.
Definitely one of the better resins I've used in my life. Now buying it by the bucket.

Product Q&A