What this industry manufactures
Gelcoat finishes the visible, mould-facing surface of FRP bathtubs, shower trays, wash basins and general sanitaryware — the smooth, coloured, easy-to-clean surface, applied before the structural laminate is built up behind it.
Why GP Gelcoat Resin is suitable
Bathware moulds are often deep, curved shapes, and GP Gelcoat Resin's thixotropic body clings to those curved mould surfaces without sagging while it gels — the same property that suits vertical hull moulds works well here too. It is not the structural material of the tub or tray: once the gelcoat has gelled, glass fibre reinforcement wet out with GP Clear Resin is built up behind it to form the actual structural shell. GP Gelcoat Resin is a general-purpose polyester gelcoat (its data sheet does not state the backbone) — some premium sanitaryware uses a more specialised gelcoat chemistry for continuous wet-service durability. Samrat's ISO Gelcoat is the isophthalic grade published for surfaces facing water contact, and the gelcoat hub compares the two routes. For a demanding commercial installation, confirm the actual service condition with the technical team rather than choosing on grade name alone — permeability is a property of the whole laminate, not of the coating by itself.
Required resin characteristics
- 01Thixotropic body that clings to deep, curved bathware mould shapes without sagging
- 02High gloss, smooth cured finish requiring no further surface work
- 03Pigmentable for the range of colours bathware and sanitaryware are commonly sold in
- 04Room-temperature MEKP cure compatible with standard mould workflows
Manufacturing process
Gelcoat is sprayed or brushed onto the open bathtub or shower tray mould first and left to gel, then glass fibre reinforcement wet out with GP Clear Resin, catalysed with an MEKP hardener and cobalt octoate accelerator, is built up behind it to form the structural shell. Once cured, the part is released from the mould with the gelcoat forming its finished, ready-to-use surface, and is trimmed and fitted with drainage and hardware.
Advantages
- Smooth, glossy, ready-to-use surface straight from the mould
- Pigmentable to match standard bathware colour ranges in a single application step
- Thixotropic body suited to deep, curved mould shapes without special equipment
- Consistent MEKP/cobalt cure across repeated production runs
Common products produced
- FRP bathtubs
- Shower trays and shower bases
- Wash basins and general sanitaryware
Frequently asked questions
No. The gelcoat is the outer surface coating, applied to the mould first. The structural shell is a separate fibreglass laminate — typically GP Clear Resin reinforced with glass fibre — built up behind the gelcoat.
Yes. GP Gelcoat Resin is supplied plain white, and FRP Polyester Pigment can be blended in before catalysing to match standard bathware colour ranges.
It is a general-purpose orthophthalic gelcoat suitable for standard FRP bathware manufacturing. Some premium sanitaryware uses a more specialised gelcoat chemistry for maximum long-term wet-service durability — for demanding commercial applications, discuss your specific requirement with our technical team.
It is cured at room temperature with an MEKP catalyst (around 1.5%) and a cobalt octoate accelerator (around 0.4%), the same system used across Samrat Poly Resins' gelcoat and general-purpose grades.
Applying it first, against the smooth mould face, is what gives the finished tub or tray its glossy surface once demoulded — there is no way to achieve the same mould-facing finish by coating the part afterward.
Need gelcoat for your bathware or sanitaryware production?
Get a bulk quote or talk to our technical team about the right gelcoat and laminate combination for your mould.