Filler Selection Guide

Fillers are used to thicket the basic resin/hardener mixture for specific applications. Each filler possesses a unique set of physical characteristics, but they can generally be categorized as either Adhesive (high-density) or Fairing (low-density).

Uses & Characteristics
with resin/hardener mixture
Adhesive Fillers

⇐  Highest Density/Highest Strength

Fairing Fillers

Lowest Density/Easiest Sanding ⇒

404-15 High-Density
404

High-Density

406-2 Colloidal Silica
406

Colloidal Silica

403-9 Microfibers, 6 oz
403

Microfibers

405 Filleting Blend
405

Filleting Blend

407-5 Low-Density
407

Low-Density

410-2 Microlight
410

Microlight™

Bonding Hardware
—Increase load capacity
—Maximum strength
­
General Bonding
—Structural gap filler
—Strong, gap-filling
Bonding with Fillets
—Increase joint bonding area
—Structural brace between parts
—Smooth, strong
Laminating
—Bond layers
—Gap-filling, strong
Fairing
—Fills voids
—Easily sanded
—Gap filling

 

Adhesive fillers are suitable for most bonding situations especially high-density materials like hardwoods and metals. Adhesive filler mixtures cure to a strong, hard-to-sand plastic useful in structural applications like bonding, filleting and hardware bonding.

Fairing filler mixtures cure to light, easily sandable material that is generally used for cosmetic or surface applications like shaping, filling or fairing. Seal all faired surfaces with epoxy before painting.

 

Additives

Additives are used to give epoxy additional physical properties when used as a coating. Although additives are blended with mixed epoxy in the same two-step process as fillers, they are not designed to thicken the epoxy (see Additives & Pigments). Follow the mixing instructions on the individual additive containers.

General use filler selection may be based on the handling characteristics you prefer. Fillers may also be blended to create mixtures with intermediate characteristics.

Filler Buying Guide

Quantity of mixed epoxy required for consistency:

 

Filler Package
Size
Package
Weight
Catsup
Consistency
Mayonnaise
Consistency
mayonnaise
Peanut Butter
Consistency
peanutbutter

403-9 Microfibers, 6 oz
403 Microfibers
403-9
403-28
403-B
6.0 oz
20.0 oz
20.0 lb
3.8 qt
3.2 gal
48.0 gal
2.5 qt
2.0 gal
32.0 gal
1.0 qt
.9 gal
15.3 gal

404-15 High-Density
404 High-Density
404-15
404-45
404-B
15.2 oz
43.0 oz
30.0 lb
1.2 qt
3.6 qt
9.4 gal
.9 qt
2.8 qt
7.4 gal
.7 qt
2.0 qt
5.3 gal

405 Filleting Blend
405 Filleting Blend
405 11.0 oz .8 qt .6 qt .5 qt

406-2 Colloidal Silica
406 Colloidal Silica
406-2
406-7
406-B
1.7 oz
5.5 oz
10.0 lb
1.3 qt
1.1 gal
27.0 gal
.9 qt
3.0 qt
16.0 gal
.5 qt
1.7 qt
6.0 gal

407-5 Low-Density
407 Low-Density
407-5
407-15
407-B
4.0 oz
12.0 oz
14.0 lb
.5 qt
1.7 qt
6.0 gal
.4 qt
1.3 qt
4.8 gal
.3 qt
1.0 qt
3.7 gal

410-2 Microlight
401 Microlight
410-2
410-7
410-B
2.0 oz
5.0 oz
4.0 lb
1.2 qt
3.0 qt
8.9 gal
.9 qt
2.4 qt
7.2 gal
7 qt
1.8 qt
5.6 gal