Polyester Fairing Compound

5 star rating

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  • Item
  • Description
  • Price
  • Qty
  • 4100/266-A
  • 4100/266-A
    Quart w/ Black BPO hardener
  • $84.95
  • 4100/266-B
  • 4100/266-B
    Gallon w/ Black BPO hardener
  • $294.95

  • 4100-A
  • 4100-A
    Quart (2.75 lbs)
  • $79.95
  • 4100-B
  • 4100-B
    Gallon (11 lbs)
  • $289.95


Durable and Highly Adhesive with Low Shrinkage

Polyester Fairing Compound is a fibrous filler for structural repairs, bonding, and part fabrication. This structural putty 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 is easy to mix, has very good 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 black 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 putty 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.

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.

  • Working Time (100 gram mass) – 8-10 minutes
  • Finish Schedule (100 gram mass) – 15-30 minutes

Requires BPO Hardener - 100R:2H (parts by weight).

#4100/266-A Kit contains (1) Quart Polyester Fairing Compound, (1) 1 oz. tube of Black BPO Hardener.

Polyester fairing compound is a versatile fibrous filler material that is commonly used for structural repairs, bonding, and part fabrication in various industries. Here are some key points about polyester fairing compound:

  1. Purpose: Polyester fairing compound is primarily used for filling gaps, voids, and damaged areas in composite structures. It helps to restore the structural integrity of the part and create a smooth, even surface for further finishing or bonding.
  2. Composition: Polyester fairing compound typically consists of a mixture of polyester resin, fillers (such as fiberglass strands or fibers), and additives. The inclusion of fiberglass strands or fibers provides additional strength and reinforcement to the compound.
  3. Strength and Durability: The fiberglass strands or fibers in polyester fairing compound enhance its strength and durability, making it suitable for structural repairs and bonding applications. The reinforced filler material helps to distribute stress and improve the overall mechanical properties of the repaired or fabricated part.
  4. Workability: Polyester fairing compound is designed to be easily mixed and applied. It can be spread with a putty knife or a similar tool, allowing for precise application and shaping. The fibrous nature of the filler material provides good adhesion and minimizes sagging or slumping during application.
  5. Bonding and Part Fabrication: Polyester fairing compound can be used for bonding composite parts together. It provides a strong bond between surfaces, ensuring structural integrity and preventing delamination. It is also suitable for fabricating composite parts, allowing for the creation of complex shapes and structures.
  6. Sanding and Finishing: Once the polyester fairing compound has cured, it can be sanded to achieve the desired shape, smoothness, and surface finish. It is compatible with various coatings and paints, allowing for further finishing and customization of the repaired or fabricated part.
  7. Storage and Shelf Life: Polyester fairing compound should be stored in a cool and dry place, away from direct sunlight and heat sources. It typically has a limited shelf life, and it is important to check the manufacturer's guidelines for specific storage and shelf-life recommendations.

When working with polyester fairing compound, it is important to follow the instructions regarding mixing ratios, curing times, application techniques, and safety precautions. This ensures proper handling, optimal performance, and desired results in structural repairs, bonding, and part fabrication.

warning WARNING: This product can expose you to chemicals including Styrene, Talc containing asbestiform fibers, and Titanium Dioxide (airborne, unbound particles of respirable size), which are known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov


Polyester Fairing Compound quart (#4100-A) and gallon (#4100-B) units and kits can be shipped via standard ground service without hazard charges within the 48 contiguous United States. All sizes of #4100 (quart and 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 Fairing Compound This fairing compound is available in two sizes: One quart (#4100-A) One gallon (#4100-B) This fairing compound can be purchased as part of a kit that includes BPO Hardener. You should purchase the kit unless you already have hardener in your workshop. Kits include: One quart of compound, with one 1 oz. tube of Black BPO Hardener (#4100/266-A) One gallon of compound, with one 4 oz. tube of Black BPO Hardener (#4100/266-B)


5 star rating

Great Bonding Product!

Jan 12, 2020  |  By Don Nagel

I used this product after a lot of research, options included "Vette" panel bonding agents, but my Factory Five Cobra is Vinylester, and only this product included that in the application guide! I love how well it mixes, I used it after cutting off both rear FRP fenders. I used Fibreglast 4100 to bond "bonding strips" I made from their vinylester and CSM material. Expensive but worth the cost! Great product!!!!


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