Lightweight Polyester Cosmetic Filler

5 star rating

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  • Item
  • Description
  • Price
  • Qty
  • 4116/266-A
  • 4116/266-A
    Quart w/ Black BPO hardener
  • $79.95
  • 4116/266-B
  • 4116/266-B
    Gallon w/ Black BPO hardener
  • $279.95

  • 4116-A
  • 4116-A
    Quart (3 lbs)
  • $74.95
  • 4116-B
  • 4116-B
    Gallon (12 lbs)
  • $269.95


High Quality No-Shrink Surface Filler

Lightweight Polyester Cosmetic Filler is a versatile, creamy paste designed to fill, seal, repair, and finish surface damage on composite materials. When applied, it quickly forms an exceptionally rigid and strong surface which can easily be sanded to a feather edge. It will not shrink, sag, or pin-hole after curing, and it can accept virtually any paint or finish without any special surface preparation. This thixotropic filler delivers excellent physical and cosmetic properties.

Apply catalyzed #4116 Lightweight Polyester Cosmetic Filler with a spatula or putty knife. After 15-20 minutes, it can be sanded to final finish.

Use #4116 Lightweight Polyester Cosmetic Filler for automotive finishing, filling in surface porosity, and a number of repair applications including bass boat hulls; composites; vacuum molds; tub and bath applications; urethane molds and parts; and cracks, dents, and crevices on worn surfaces. When cured, this filler adheres to fiberglass, SMC, RIM, BMC, plaster, graphite, KEVLAR®, steel, iron, and copper.

For applications that require a structural repair, first use #4100 Polyester Fairing Compound. #4100 Polyester Fairing Compound is a fibrous putty used to rebuild broken, void, or damaged areas. Once cured, apply #4116 Lightweight Polyester Cosmetic Filler over the repair to achieve a smooth, cosmetic surface.

  • Resin Color – Off-White
  • Working Time (100 gram mass) – 5 ± 1 minutes
  • Finish Schedule (100 gram mass) – 15 minutes

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

warning WARNING: This product can expose you to chemicals including Styrene & Titanium Dioxide (airborne, unbound particles of respirable size), which are known to the State of California to cause cancer. For more information go to


Lightweight Polyester Cosmetic Filler quart unit (#4116-A) and kit can be shipped via standard ground service without hazard charges within the 48 contiguous United States. #4116-A quart unit and kit 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.


Lightweight Polyester Cosmetic Filler This fairing compound is available in two sizes: One quart (#4116-A) One gallon (#4116-B) This filler 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 filler, with one 1 oz. tube of Black BPO Hardener (#4116/266-A) One gallon of filler, with one 4 oz. tube of Black BPO Hardener (#4116/266-B)


5 star rating


Jan 24, 2023  |  By SANDY RODRIGUEZ

Great ! Lightweight , fills in void and bonds great, sands respectfully easy for what it is and paints over smooth

Use a gram scale and dark hardener for best result

Jan 29, 2021  |  By Jim

This is my second quart (3 pound) can of 4116. My experience with the first can started poorly, but ended up fine. I've seen plenty of videos where people scoop out "some" filler and add "some" BPO hardener, but most of the time I couldn't estimate correct amounts of each, and I ended up with a sticky result. Or, maybe I wasn't getting it mixed well (although I mixed it a lot).

At some point the BPO tube broke while I was kneading it before using it. I almost discarded the remaining filler because I was usually frustrated with the result anyway; instead I ordered a tube of black BPO. I also bought a Taylor digital scale that measures up to 454 grams (or 16 ounces). (Found the scale in the kitchen department of my local discount department store for about $13.)

Using the scale and dark hardener gave me consistent results. I can accurately get the required 50:1 ratio of filler to hardener and I can be sure the two are well mixed. Just weigh the amount of filler you want (use grams for better resolution), divide that by 50 to determine how many grams of BPO to add, then mix.

The result is light grey and covers fine with white gel coat. Most times I wish it wouldn't cure quite so fast but that's usually only a problem on smaller parts where you're trying to get a detailed shape right. Wide open, flat areas aren't usually a problem.

Lwt Weight Fairing Compound

Nov 22, 2015  |  By Karsten

This stuff is great and a little goes a long way.

Being a novice at best on my 1st boat Resto/Gelcoat the team at Fibreglast have been awesome in recommending what is needed to get this done.

The fairing compound is simple and a little goes along way. As with other filler putty use it sparingly and build it up in thin layers sanding between layers.

I am waiting for my 2nd order of materials from Fibreglast of the various Gelcoat Additives and hopefully after the 1st of the year I will be ordering 5 gallons of Clear Gel. a gallon of Burnt Orange to have on hand when the weather warms up.

Fiberglass Finishing
Sep 21, 2015  |  By John
Excellent qualities, easy to work with and provides an excellent surface for painting

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