Resin consumption per square foot per layer. Vacuum bagging uses 25-35% less resin than hand layup due to vacuum compression at 20-25 inHg.

These rates cover wet-out: the resin needed to fully saturate the cloth (roughly 1:1 with the dry glass weight, since 6 oz cloth is about 0.67 oz per square foot). To bury the weave for a smooth finish, add about 0.3 oz per square foot for each fill coat. Waste factor covers mixing waste, drips, and pot-life losses; biaxial, carbon, and Kevlar carry a higher waste factor due to more complex wet-out.

How much surface area one gallon of resin covers at each flood coat thickness. Coverage shown before and after accounting for 15% waste (edge drips and mixing losses).

Most tabletop projects use a thin seal coat first (0.32 oz/sqft), then one or two flood coats. The seal coat prevents air bubbles from wood outgassing into the flood coat.

A cove fillet fills the concave corner the filleting tool leaves behind, so the cross-section is the square corner minus the quarter-round the tool sweeps out: about 0.215 times the radius squared, not a solid quarter-circle. Larger radius fillets use significantly more resin per foot of joint. All values include 15% waste factor.

Fillets use thickened resin (mixed with colloidal silica or wood flour). The thickener itself adds negligible volume - estimate based on liquid resin volume.

A seal coat is a thin brush-on layer of un-thickened resin applied to raw wood before layup or flood coating. It penetrates the grain, prevents air bubbles from outgassing, and improves adhesion.

Properties vary by manufacturer and formulation. Values below are typical ranges for marine-grade resins at 77°F (25°C).

Viscosity and Working Characteristics

Viscosity determines how easily resin wets out fabric. Lower viscosity resins flow into weave more readily, while higher viscosity resins stay put on vertical surfaces. Epoxy is the thickest of the three but offers the best mechanical properties and near-zero shrinkage - critical for marine applications where watertight integrity matters.

Temperature effects: Viscosity drops as temperature rises. Working at 75-85°F gives optimal flow. Below 60°F, epoxy becomes sluggish and may not cure properly. Above 90°F, pot life shortens dramatically - mix smaller batches.

Epoxy Cure Speed and Mix Ratios

Epoxy hardeners come in different speeds. The mix ratio changes with the hardener - this is not interchangeable. Using the wrong ratio will result in a soft, under-cured layup.

The exact formulas this calculator uses. All results are rounded to two decimal places.

Fiberglass / Vacuum Bagging

Example: 50 sqft of 6 oz cloth, 2 layers, hand layup gives 50 × 2 × 0.73 ÷ 128 × 1.15 = 0.66 gallons

Tabletop Flood Coat

Example: 12 sqft at 1/8" thick gives (12 × 144 × 0.125) ÷ 231 × 1.15 = 1.08 gallons

Fillet Joint

Example: 30 linear feet at 3/4" radius gives (0.75² × 0.215 × 30 × 12) ÷ 231 × 1.15 = 0.22 gallons

Seal Coat

Example: 50 sqft seal coat gives (50 × 0.32) ÷ 128 × 1.10 = 0.14 gallons

Constants Used

How much resin do I need per square foot of fiberglass cloth?

For 6 oz fiberglass cloth, plan on about 0.73 ounces of resin per square foot per layer to wet out the cloth, which is roughly a 1:1 ratio with the dry glass weight. To bury the weave for a smooth finish, add about 0.3 ounces per square foot for each fill coat. Heavier fabrics use more: 10 oz cloth runs about 1.22 ounces per square foot per layer, and 1708 biaxial about 4.0.

How much epoxy do I need for a tabletop or bar top?

A standard 1/8 inch flood coat covers about 11 square feet per gallon after waste, so a 12 square foot top needs roughly 1.08 gallons. A thinner 1/16 inch coat covers about 22 square feet per gallon, and a thick 1/4 inch deep-pour look about 5.6 square feet per gallon.

How much resin does an epoxy fillet use?

A cove fillet only fills the concave corner the filleting tool leaves behind, so it uses less than a solid quarter-round would suggest. A standard 3/4 inch fillet uses about 0.07 gallons per 10 linear feet, and a 1 inch fillet about 0.13 gallons per 10 feet.

What is the epoxy resin to hardener mix ratio?

Epoxy is measured by volume and the ratio depends on the hardener speed: slow hardener is 2:1 resin to hardener, medium is 3:1, and fast is 4:1. Polyester and vinyl ester instead use 1 to 2 percent MEKP catalyst by weight.

Should I use epoxy, polyester, or vinyl ester resin?

Epoxy has the best adhesion, strength, and near-zero shrinkage, which makes it the choice for repairs and bonding to wood, and it costs the most. Polyester is the most economical and cures fast, but shrinks more and has a stronger odor. Vinyl ester sits in the middle on price with excellent water and chemical resistance.