Fiberglass Resin Calculator
Estimate resin, MEKP catalyst, laminate weight, and cured thickness for hand lay-up with chopped strand mat (CSM) — before you order materials.
Results
| Glass (CSM) | 0.5 kg |
| Resin | 1.0 kg |
| MEKP catalyst | 15 g |
| Total laminate | 1.4 kg |
| Estimated cured thickness | 0.96 mm |
What This Calculator Does
The fiberglass resin calculator estimates material quantities for hand lay-up with chopped strand mat. Enter the mat weight in g/m², the laminate area in m², the number of layers, the resin:glass ratio, and the MEKP catalyst percentage, and it returns the glass weight, the resin weight, the catalyst needed, the total laminate weight, and an estimate of cured thickness. The calculations are:
- Glass (kg) = mat weight (g/m²) × area (m²) × layers ÷ 1000
- Resin (kg) = glass (kg) × resin:glass ratio
- MEKP catalyst = resin (kg) × catalyst % ÷ 100
- Total laminate (kg) = glass (kg) + resin (kg)
- Cured thickness (mm) ≈ mat weight × layers × (1 + ratio) ÷ 1500
For example, one layer of 450 g/m² CSM over 1 m² at the default 2.2:1 ratio gives 0.45 kg of glass, 0.99 kg of resin, about 15 g of MEKP catalyst at 1.5%, and a total laminate weight of about 1.44 kg. The same inputs estimate 0.96 mm of cured thickness.
How to Use It
- Enter the CSM weight in g/m² — common production weights include 300, 450, and 600 g/m².
- Enter the laminate area in m².
- Set the number of CSM layers in the stack.
- Adjust the resin:glass ratio slider within the typical hand lay-up range of 2.0–2.5:1.
- Set the MEKP catalyst percentage, normally 1–2% of resin weight depending on temperature and gel time.
Assumptions
- The 2.0–2.5:1 resin:glass ratio is a typical hand lay-up industry value; actual consumption depends on operator technique, part geometry, and whether the laminate is rolled or sprayed.
- MEKP at 1–2% by weight is the typical range for room-temperature curing of polyester and vinyl ester resins.
- The thickness estimate assumes a cured CSM laminate density of about 1.5 g/cm³.
- At the default inputs, 450 g/m² × 1 layer at 2.2:1 estimates 0.96 mm — consistent with the “about 1 mm per 450 g/m² layer” rule of thumb published in our hand lay-up guides.
- Results exclude gel coat, trim waste, and overspray.
Data Sources and Verification
- Resin:glass ratios of 2.0–2.5:1 by weight: industry rule of thumb based on glass content targets of 25–35% in hand-laid laminates.
- MEKP catalyst at 1.0–2.0% by weight: typical ranges from unsaturated polyester resin technical data sheets; actual values vary by formulation and ambient temperature.
- Cured CSM laminate density of about 1.5 g/cm³: typical assumption used for thickness estimation.
- The worked example matches the calculation published in our fiberglass resin guide.
Ready to Order?
Once the estimate matches your laminate schedule, send it with your RFQ. We supply CSM in weights from 100 to 900 g/m², emulsion or powder bound, with MOQ from 2 tons.