How do you calculate resin needed for vacuum infusion?

Take the dry reinforcement weight, scale it by the resin-to-fiber mass ratio implied by your target fiber volume fraction and the resin and fiber densities, then add a waste allowance. The result is the resin quantity to order for the shot.

What is a good fiber volume fraction for marine infusion?

Well-controlled glass infusions typically reach 50-60% by volume and carbon a little higher; the 55% default sits in the sweet spot of strength versus wet-out reliability.

How much resin waste should I allow?

Allow for resin left in feed lines, the catch pot, flow media, and the leading flow front. A 10% allowance is common for clean setups; complex parts with long runners may need 15-20%.

Why does a higher fiber volume fraction lower resin use?

A higher fiber fraction means less void space between fibers to fill, so proportionally less resin is needed; pushing the fraction too high, though, risks dry spots and incomplete wet-out.

Does core material change the resin estimate?

Yes. Grooved or perforated cores and exposed core cells absorb extra resin that this fiber-based estimate does not capture, so add core absorption separately for cored laminates.

Should I order extra beyond the calculated total?

Always round up to full container sizes and keep a contingency, because a single infusion cannot be paused to mix more resin without risking a dry laminate.

Marine, Shipbuilding & Boat Manufacturing calculator

Resin Infusion Material Estimate Calculator

This resin infusion material estimate predicts how much resin you must order to fully wet out a dry reinforcement stack at a target fiber volume fraction. Composite engineers, infusion technicians, and purchasers in boatbuilding rely on it to buy the right resin quantity, avoid mid-shot shortages, and control the resin-to-fiber ratio that drives laminate weight and strength. Under-ordering risks a dry, scrapped part during a one-shot infusion; over-ordering wastes expensive resin and adds dead weight. It converts a fiber weight and a target fraction into a purchasing quantity with waste built in.

What this calculator does

Calculate total resin quantity needed for a vacuum infusion layup based on dry fabric weight, fiber volume fraction target, and waste allowance for feed lines, mixing, and bleed-off.
Use it before ordering resin for a vacuum infusion hull, deck, or structural part to avoid short pours or excessive leftover material.
It computes net resin needed to reach a target fiber volume fraction from the dry reinforcement weight, then adds a waste allowance to give a total resin quantity to order.

Formula used

Net resin required = dry reinforcement weight x ((100 - fiber volume fraction) / fiber volume fraction) x (resin density / fiber density)
Total resin to order = net resin required x (1 + waste allowance / 100)

Inputs explained

Total dry reinforcement weight:
Target fiber volume fraction:
Resin waste allowance:

How to use the result

Use it when planning a vacuum-infusion shot or buying resin for a hull, deck, or structural part before a one-shot infusion.
Fiber volume fraction is a target, not a guarantee; real infusions vary with bag pressure, flow media, and core absorption, so the as-built ratio can drift from the entered value.

Current U.S. benchmarks

U.S. housing starts run at 1,177k per year (Census, May 2026), down 8.7% from a year earlier, the demand driver for building products.
The U.S. has 11,691 transportation equipment establishments employing about 1,682,910 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate resin needed for vacuum infusion? Take the dry reinforcement weight, scale it by the resin-to-fiber mass ratio implied by your target fiber volume fraction and the resin and fiber densities, then add a waste allowance. The result is the resin quantity to order for the shot.
What is a good fiber volume fraction for marine infusion? Well-controlled glass infusions typically reach 50-60% by volume and carbon a little higher; the 55% default sits in the sweet spot of strength versus wet-out reliability.
How much resin waste should I allow? Allow for resin left in feed lines, the catch pot, flow media, and the leading flow front. A 10% allowance is common for clean setups; complex parts with long runners may need 15-20%.
Why does a higher fiber volume fraction lower resin use? A higher fiber fraction means less void space between fibers to fill, so proportionally less resin is needed; pushing the fraction too high, though, risks dry spots and incomplete wet-out.
Does core material change the resin estimate? Yes. Grooved or perforated cores and exposed core cells absorb extra resin that this fiber-based estimate does not capture, so add core absorption separately for cored laminates.

Last reviewed 2026-05-12.