Quick facts
- Catalogue code
- SPR 201 FR-GC
- Chemistry
- Thixotropic fire-retardant orthophthalic gelcoat
- Role
- Mould-face surface of fire-retardant FRP parts
- Terephthalic counterpart
- SPR 401 FRGC
A gelcoat for fire-retardant parts
A gelcoat is the first layer in the mould: sprayed or brushed onto the mould face before any glass or laminating resin, it becomes the surface of the finished part. A fire-retardant part built with a fire-retardant laminate still has that outer skin, and a standard gelcoat there would be the weak surface of an otherwise fire-retardant construction. SPR 201 FR-GC is the orthophthalic gelcoat made for that surface.
The catalogue lists rail and metro composite components, automotive FRP components and surface gelcoat for fire-retardant FRP laminates, and pairs it with the family’s fire-retardant laminating resins.
Reading the published values
A gelcoat’s viscosity is published at two shear rates because it is thixotropic: it must thin to spray or brush and thicken so it does not run on a vertical mould. The catalogue lists 5,000–11,000 cPs at high shear and 30,000–45,000 cPs at low shear (both at 25 °C), a gel time of 9–16 minutes at 25 °C, a specific gravity of 1.35–1.55 and 17–25% styrene by weight. It is supplied non-accelerated and thixotropic, with MEKP 1.5–2.0% added during use as the reference cure.
The appearance is milky white to grey, with custom-tinted variants where supplied.
Limitations and alternatives
The gelcoat is one layer of a construction. Its fire-retardant formulation does not give the part a fire rating; the finished construction is tested to the standard the project names. For a non-fire-retardant part, the standard white SPR 201 GC gelcoat is the general choice. The range also carries a terephthalic fire-retardant gelcoat, SPR 401 FRGC, with its own specification.
Source, roles and the Nepal enquiry path
The values on this page are the typical specification printed for SPR 201 FR-GC in the supplier’s 2026 product catalogue. Samrat Poly Resins has since published a Technical Data Sheet for this grade, linked from the product page; its figures and the catalogue’s agree, and the catalogue is the source named beside every figure here.
Samrat Poly Resins, India manufactures the grade and issues its technical information. Samrat FRP Traders is the Nepal supplier and importer and handles enquiries; price, packaging, lead time and stock in Nepal are confirmed on enquiry.
Key properties
| Property | Typical value |
|---|---|
| Appearance | Milky white to grey opaque liquid; custom-tinted variants where supplied |
| Viscosity — high shear | 5,000–11,000 cPs at 25 °C |
| Viscosity — low shear | 30,000–45,000 cPs at 25 °C |
| Gel time | 9–16 minutes at 25 °C |
| Specific gravity | 1.35–1.55 |
| Styrene content | 17–25% by weight |
| Supply condition | Non-accelerated · thixotropic |
| Reference cure system | MEKP 1.5–2.0% — added during use |
Source: Samrat Poly Resins, India — product catalogue, 2026 edition (typical specification). Typical values describe the grade; they are not batch guarantees or acceptance limits.
Frequently asked questions
Can I use it as a laminating resin?
No. It is a gelcoat: the surface layer applied to the mould before lay-up. The laminate behind it uses a fire-retardant laminating resin.
Why are there two viscosity figures?
Because the gelcoat is thixotropic. The high-shear figure describes it while being sprayed or brushed; the low-shear figure describes it at rest on the mould.
How is it different from SPR 401 FRGC?
SPR 401 FRGC is a terephthalic fire-retardant gelcoat with its own published values. The comparison guide sets the two side by side.