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WEST SYSTEM 403-28 Microfibers, 20 oz

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$51.93

$ 24 .99 $24.99

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About this item

  • THIS BLEND OF FINE FIBERS thickens mixed epoxy resin and hardener to create a multi-purpose adhesive. Its most popular use is for bonding wood. Epoxy thickened with microfibers has good gap-filling qualities but will still do an excellent job of wetting-out/penetrating into wood fibers. Use it to thicken any WEST SYSTEM Epoxy including 105 Resin-based epoxies, G/flex or G/5. Blended with epoxy, it will cure to an off-white color.
  • THICKEN EPOXY with this high-density filler to make a non-slumping adhesive that will bridge large gaps. It will strongly bond wood joints, saving you the time and labor involved in crafting tight joinery.
  • FOR MAXIMUM STRENGTH add only enough filler to completely bridge gaps between surfaces without sagging or running out of the joint or gap. A small amount should squeeze out of the joints when clamped. For thick mixtures, don’t fill the mixing cup more than 1/3 full of epoxy before adding filler.
  • THE AMOUNT OF FILLER you add controls epoxy's viscosity. There is no strict formula, just use your eye to judge what consistency will work best for the job at hand. The chart below offers guidelines to the differences between neat (unthickened) epoxy and three popular consistencies of thickened epoxy: "catsup," "mayonnaise," and "peanut butter."
  • FOR CONSISTENCY across a project that calls for several batches of epoxy that's thickened to the same degree, you can create your own epoxy/filler "recipe." Carefully measure the amount of filler you add to the first epoxy batch until it reaches the viscosity you need, keeping track of the total amount you've added. Mix the same amounts of resin, hardener, and filler for the remaining batches so they all have the same viscosity.



Product Description

WEST SYSTEM Fillers modify the consistency of epoxy, greatly increasing its versatility for a wide array of applications

Unthickened epoxy has a syrup-like consistency

Syrup Consistency (unthickened resin/hardener mixture or "neat" epoxy)

  • CONSISTENCY: Unthickened epoxy, syrup

  • CHARACTERISTICS: Drips off vertical surfaces

  • USES: Coating; wetting out surfaces before bonding; applying fiberglass, graphite, and other reinforcing fabrics

Slightly thickened epoxy has a catsup-like consistency

Catsup Consistency (slightly thickened)

  • CONSISTENCY: Slightly thickened epoxy, slurry
  • CHARACTERISTICS: Sags down vertical surfaces
  • USES: Laminating or bonding flat panels with large surface areas, injecting into holes with a syringe

Moderately thickened epoxy has a mayonnaise-like consistency

Mayonnaise Consistency (moderately thickened)

  • CONSISTENCY: Moderately thickened epoxy mixture, creamy
  • CHARACTERISTICS: Clings to vertical surfaces; peaks fall over
  • USES: General bonding, filleting, hardware bonding

Heavily thickened epoxy has a peanut butter-like consistency

Peanut Butter Consistency (maximum workable thickness)

  • CONSISTENCY: Maximum thickness epoxy mixture, dense
  • CHARACTERISTICS: Clings to vertical surfaces; peaks stand
  • USES: Gap filling, filleting, fairing, bonding uneven surfaces
WEST SYSTEM Epoxy products come in an array of versatile formulations

Versatile, reliable WEST SYSTEM products

WEST SYSTEM offers high-quality epoxy resins, hardeners, fillers, and additives. Developed by our in-house chemists, our formulations are proprietary, structural, and marine grade. These epoxies have set the standard for epoxy quality in the marine industry and beyond since 1969.

WEST SYSTEM Product Selection Guide

WEST SYSTEM 105 Resin can be paired with one of 4 hardeners and modified with fillers & additives.

How to choose the right WEST SYSTEM Epoxy products for your project:

1. Start with 105 Epoxy Resin, the basic ingredient of all WEST SYSTEM Epoxy compounds. Use 300 Mini Pumps for convenient and accurate metering.

2. Mix with one of four WEST SYSTEM hardeners. Select a hardener for its intended use and for the cure speed best suited for your job in the temperature range in which you are working.

3. Add one of six WEST SYSTEM fillers to thicken the mixture as needed. Select a filler for its handling characteristics or cured physical properties. Or, add WEST SYSTEM additives to provide specific coating properties. WEST SYSTEM pigments can be used to change the epoxy's color.

Pigments for tinting epoxy

501 White Pigment for WEST SYSTEM Epoxy

501 White Pigment

501 White Pigment is an epoxy-based liquid colorant used to tint the epoxy mixture white, providing an even, white color base for the final finish system. Cured, pigmented epoxy surfaces are not a final finish surface, but require an additional paint or UV filter coating for ultraviolet protection. Add to the mixed resin/hardener at a rate of approximately one teaspoon of pigment to 8 fl oz of epoxy. More pigments will increase opaqueness and mixture viscosity. One 4 fl oz bottle will tint approximately 1.5 gal of epoxy.

Adding a coloring agent to WEST SYSTEM Epoxy is frequently done to make colored castings, highlight an epoxy-coated surface, act as a colored base coat for paint, etc.

Without exception, adding pigment will weaken the cured epoxy mixture to some degree. Use very small amounts of pigment, about 5% by weight. As a result, thin films of colored epoxy are somewhat transparent. It usually requires several coats to make the film opaque.

502 Black Pigment for modifying WEST SYSTEM Epoxy

502 Black Pigment

502 Black Pigment is an epoxy-based liquid colorant used to tint the epoxy mixture black, providing an even, black color base for the final finish system. Cured, pigmented epoxy surfaces are not a final finish surface, but require an additional paint or UV filter coating for ultraviolet protection. Add to the mixed resin/hardener at a rate of approximately one teaspoon of pigment to 8 fl oz of epoxy. More pigments will increase opaqueness and mixture viscosity. One 4 fl oz bottle will tint approximately 1.5 gal of epoxy.

Adding a coloring agent to WEST SYSTEM Epoxy is frequently done to make colored castings, highlight an epoxy-coated surface, act as a colored base coat for paint, etc.

Without exception, adding pigment will weaken the cured epoxy mixture to some degree. Use very small amounts of pigment, about 5% by weight. As a result, thin films of colored epoxy are somewhat transparent. It usually requires several coats to make the film opaque.

503 Gray Pigment for modifying WEST SYSTEM Epoxy

503 Gray Pigment

503 Gray Pigment is an epoxy-based liquid colorant used to tint the epoxy mixture gray, providing an even, gray color base for the final finish system. Cured, pigmented epoxy surfaces are not a final finish surface, but require an additional paint or UV filter coating for ultraviolet protection. Add to the mixed resin/hardener at a rate of approximately one teaspoon of pigment to 8 fl oz of epoxy. More pigments will increase opaqueness and mixture viscosity. One 4 fl oz bottle will tint approximately 1.5 gal of epoxy.

Adding a coloring agent to WEST SYSTEM Epoxy is frequently done to make colored castings, highlight an epoxy-coated surface, act as a colored base coat for paint, etc.

Without exception, adding pigment will weaken the cured epoxy mixture to some degree. Use very small amounts of pigment, about 5% by weight. As a result, thin films of colored epoxy are somewhat transparent. It usually requires several coats to make the film opaque.

Additives for modifying epoxy

420 Aluminum Powder for modifying WEST SYSTEM Epoxy

420 Aluminum Powder

420 Aluminum Powder will increase the hardness and abrasion resistance of the coated surface and improve its moisture resistance. 420 provides limited protection from ultraviolet light in areas that will not be protected with other coatings and can be used as a base for subsequent painting. Cures to a metallic gray color.

Add to mixed resin/hardener at the rate of 5%-10% by volume or 1.5 tablespoons per 8 fl oz of epoxy (10 strokes each of resin and hardener from 300 Mini Pumps). 36 oz of 420 will modify up to five gallons of mixed epoxy.

422 Barrier Coat Additive for modifying WEST SYSTEM Epoxy

422 Barrier Coat Additive

422 Barrier Coat Additive is a proprietary blend designed to further improve cured epoxy’s moisture exclusion effectiveness. 422 is used as a barrier coating additive to help prevent gelcoat blistering in polyester fiberglass boats. 422 also increases the epoxy’s abrasion resistance. Cures to a light gray color.

Add to mixed resin/hardener at the rate of 15 to 20% by volume or 3 tablespoons per 8 fl oz of epoxy. 16 oz can of 422 will modify approximately half a gallon of mixed epoxy.

423 Graphite Powder for modifying WEST SYSTEM Epoxy

423 Graphite Powder

423 Graphite Powder is a fine black powder that can be mixed with epoxy to produce a low-friction exterior coating with increased scuff resistance and durability.

Epoxy/graphite is commonly used as a low-load, low-speed bearing surface, as a coating on rudders and centerboards, or on the bottoms of racing craft that are dry sailed. It does not provide antifouling qualities. The epoxy/graphite mixture cures to a black color.

Add to mixed resin/hardener at the rate of 10% by volume or 1.5 tablespoons per 8 fl oz. of epoxy. 12 oz can of 423 will modify approximately one gallon of epoxy.


bzqa
Reviewed in the United States on February 5, 2024
Epoxy bonding sister beams to very-badly cut/compromised floor joists. Using the 209 very slow hardener and this thickening additive for a mayo/peanut butter consistency gave was a perfect combination for this large and fairly time-consuming job.
Tiny Home Builder
Reviewed in the United States on July 4, 2023
I use this to thicken in corners. Very strong. Stronger than 410 which I use for smoothing minor. If I have a big dent/gap, I'll fill with this, then smooth with the 410. I mix this by dumping epoxy (half coffee cup size) on a board, then mixing with this using spackle knife. Best to drag the knife over and over in assorted directions. little goes a long way. Maybe half coffee cup of powder to coffee cup of epoxy. Last note- just started using seringes in 1/3 to 3 sizes to mix my epoxy- so much easier than cups to determine volume. Over and over use and low cost here. I use 20ml and 60 ml seringes and the volume for worability is great. Lastly- bakers bag to squish into corners on runs is best apply method I've come up with rounding floor to walls with small rollers.
Brandy Shell
Reviewed in the United States on October 15, 2023
I bought this to fix my Hoosier cabinet. It done the job.
Customer
Reviewed in the United States on October 14, 2022
Large quantity high quality
Wayne A.
Reviewed in the United States on August 31, 2021
I have used this filler to build boats and to repair a house foundation rotting away. Great as a thickener and and structural filler (though I recommend the High Density filler for structural work): especially good as a glue for joining wood.
Mary Alice Osborne
Reviewed in the United States on October 5, 2020
Easy to mix with resin. Can be used to make medium to stiff putty.
Yi-Ling Lin
Reviewed in the United States on August 2, 2019
This product is very easy to use. I used it to repair rotten frame of my balcony. I live in a condo, in which I can only do a localized repair. I followed the instruction by mixing the resin and hardener with 5 to 1 ratio. I then mixed it with microfiber to adjust the thickness of the mixture. I filled the defected area and it worked very well. I had no problem to drill hole and fastened screws in the repaired area. the product strengthening the wood very well. I will give the product five stars.
Dino
Reviewed in the United States on February 16, 2019
A perfect additive to the WEST epoxy.
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