Epoxy laminating resin

Physical properties

Laser processing

During curing and any thermal processing, the hardener amines release irritating and sensitizing vapours. On composite laminates (glass/carbon), there is the added risk of inhalable silica and carbon fibres. HEPA + activated carbon extraction is mandatory.

CO₂: Thermoset material: does not melt or cut with CO2 laser. Decomposition generates dense, toxic smoke with release of gaseous BPA and epoxy matrix fragments. If laminated with glass or carbon fibre, the risk increases dramatically due to the presence of volatilized mineral fibres.

Diode: Not applicable.

Fiber: Not applicable in maker contexts.

CNC / milling processing

CNC-machinable only after complete curing (at least 24 h at room temperature or post-cure in an oven). Composites laminated with glass or carbon fibre require tungsten carbide or diamond-coated tools. High speeds (18.000–25.000 RPM), low feed rates, dedicated extraction. Do not use HSS bits: they wear out in just a few passes.

Post-processing

Sanding: Sanding possible on fully cured laminates, starting from 80–120 grit and progressing to 320–400 for surfaces to be painted. Always wet-sand when possible to limit fibre dust. FFP3 mask mandatory.

Primer: Epoxy or polyester gelcoat is the standard finish for construction-grade laminates. For conventional painting, use two-component epoxy primer to ensure adhesion.

Gluing: Excellent compatibility with structural two-component epoxy adhesives. The surface must be sanded with 80 grit and degreased with acetone. On cut edges of the laminate, the adhesive penetrates the porous structure of exposed fibres, ensuring a strong mechanical bond.

Over time: Excellent UV resistance if protected with gelcoat or UV varnish. Without surface protection, the epoxy matrix tends to yellow and suffer osmosis in humid environments over the long term. Excellent chemical resistance to solvents, fuels, and petroleum products.

Common defects

• Delamination between fabric plies and matrix due to insufficient impregnation or trapped air bubbles during lay-up
• Dry spots (white, resin-starved areas) from incorrect resin/fibre ratio — visible in transmitted light
• Excessive exotherm in thick laminates — work in layers not exceeding 5mm per pass
• Surface inhibition (tacky surface) from oxygen contact — use peel ply or cover layer in hand lay-up

Safety

Recommended PPE: gloves_nitrile, mask_p3, eye_protection

The amine hardener (component B) is strongly irritating to skin and mucous membranes. Repeated contact causes permanent skin sensitization. Double-layer nitrile gloves, sealed goggles, mask with P3+A1 filter for mixing and lamination. Do not work in enclosed spaces without forced air exchange.

Availability and formats

Commercial formats: two-part A+B kits in 5kg, 10kg, 30kg formats, low-viscosity formulations for vacuum infusion (500–800 mPa·s), formulations for hand lay-up (1000–2000 mPa·s)

Related materials

Sources

• Hexion — EPIKOTE Resin MGS LR 135 Technical Data Sheet
• Sicomin — SR 8100 Laminating System TDS
• West System — Product Guide for Marine Use