Marine, Shipbuilding & Boat Manufacturing worked example

Fiberglass Hand Layup Resin Usage at 7.2% catalyzed resin waste allowance: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop catalyzed resin waste allowance to 7.2%, then walk the calculation through step by step. Calculate resin quantity for hand layup based on fiberglass fabric weight, resin-to-glass ratio, and waste allowance for catalyzed resin that gels before use.

The inputs for this scenario

  • Total dry glass fiber weight: 80 kg (held at the documented default)
  • Resin-to-glass ratio: 1.8 ratio (held at the documented default)
  • Catalyzed resin waste allowance: 7.2 % (the input this scenario stresses; the baseline uses 10)

Working through the calculation

  • The calculation starts from the formula this tool documents: Net resin required = dry glass weight x resin-to-glass ratio.
  • Total resin to order works out to 2,000 kg at these inputs, and this is the headline figure for the scenario.
  • Net resin required (no waste) works out to 144 kg at these inputs.
  • Catalyzed resin waste works out to 1,856 kg at these inputs.
  • Resin utilization rate works out to 7.2 % at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where catalyzed resin waste allowance sits at 10% and the headline result is 1,440 kg, this scenario comes in 38.89% above the baseline at 2,000 kg.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to catalyzed resin waste allowance, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It assumes uniform wet-out at one ratio; cored sandwich panels, vacuum infusion, and heavily contoured parts have very different resin demand than open hand layup.

Results at a glance

  • Total resin to order: 2,000 kg (headline result)
  • Net resin required (no waste): 144 kg
  • Catalyzed resin waste: 1,856 kg
  • Resin utilization rate: 7.2 %

Run it with your numbers

  • To rerun this with your own numbers, open the live Fiberglass Hand Layup Resin Usage calculator, set catalyzed resin waste allowance to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.