Arcstruct CM 210 Pigmented In-Mould Gel Coat
Unsaturated polyester gel coat applied to the prepared mould face before lay-up, forming the visible outer surface of the finished moulding and controlling its colour and its resistance to weathering and water. It cures against polished tooling, which is what gives a mould-quality finish, and is supplied in general purpose, weather-resistant isophthalic and low styrene emission grades.
Grade Arcstruct CM 210 | Range Industrial and Infrastructure Coatings | Technology Unsaturated polyester in styrene monomer, pigmented, cured with organic peroxide
Technical Data Sheet
Arcstruct CM 210
Issue 2026.09
1. Product description
Unsaturated polyester gel coat applied to the mould face before lay-up, forming the visible outer surface of the finished moulding once it is released. It controls surface quality, colour and resistance to weathering and water, and is the only layer that can produce a mould-quality finish because it cures against polished tooling. Supplied in general purpose, weather-resistant isophthalic and low styrene emission grades for workshops managing operator exposure.
2. Features
- Mould-quality surface cured against polished tooling
- Controls colour, weathering and water resistance of the moulding
- General purpose, isophthalic and low styrene emission grades
- Catalyst level set by workshop temperature
- Also used for gel coat repair and patching on cured laminates
3. Recommended uses
Pigmented outer surface of glass-reinforced polyester and vinyl ester mouldings made by lay-up against a mould, and repair or patching of gel coat on cured polyester and vinyl ester laminates.
Substrates. Prepared and waxed mould tooling. Also used on cured polyester and vinyl ester laminates for gel coat repair and patching, where the repair is cured against a film or dressed back after cure
4. Typical properties
| Property | Typical value | Method |
|---|---|---|
| Technology | Unsaturated polyester in styrene monomer, pigmented, cured with organic peroxide | Formulation |
| Appearance | Pigmented thixotropic liquid; the cured film reproduces the mould surface | Visual |
| Resin type | General purpose, weather-resistant isophthalic or low styrene emission unsaturated polyester, by grade | Formulation |
| Viscosity | Thixotropic; apparent viscosity at two spindle speeds issued with the Certificate of Analysis | ISO 2555 |
| Density | 1.2 to 1.4 g/cm3 | ISO 2811-1 |
| Gel time at 25 degrees Celsius | 10 to 25 minutes at the reference catalyst level | ISO 2535 |
| Applied wet film | 400 to 700 micrometres | ISO 2808, wet film comb |
| Barcol hardness, cured gel coat casting | 35 to 45 | ASTM D2583 |
| Gloss from polished tooling | Above 70 at 60 degrees | ISO 2813 |
| Accelerated weathering, isophthalic grade | 1000 to 2000 hours fluorescent UV with condensation cycling, with gloss retention and colour change reported | ISO 16474-3 or ASTM G154 |
Typical values, not a specification. Values for each batch are given on its Certificate of Analysis.
5. Application
| Parameter | Guidance |
|---|---|
| Mould preparation | Clean, sealed and waxed or release-treated mould at workshop temperature, free of dust and moisture. |
| Catalyst | Organic peroxide at 1.5 to 3 per cent by weight, set by workshop temperature, mixed thoroughly without entraining air. |
| Application method | Gel coat spray gun, or brush on small tooling. |
| Wet film | 400 to 700 micrometres in one or more passes, checked with a comb; a thin film under-cures and wrinkles at lay-up, and an over-thick film is prone to cracking. |
| Conditions | Workshop and mould typically 18 to 30 degrees Celsius; the working window shortens as the shop warms. |
| Next step | Left to gel, then lay-up begins within the working window. |
| Repair use | On cured laminates, the area is abraded and cleaned, the gel coat applied and cured against a film or dressed back after cure. |
Process. Spray applied with a gel coat gun, or brushed on small tooling, to a controlled wet film. Catalysed with organic peroxide at a ratio set by workshop temperature. Left to gel before lay-up begins, with a working window that shortens as the shop warms
6. Storage and handling
Store in the original closed containers in a cool, dry place out of direct sun, at 5 to 25 degrees Celsius, since warm storage reduces storage stability and shifts gel time; stir gently to redisperse before use. Shelf life is stated on the label and the Certificate of Analysis. Handle and use the product in line with its Safety Data Sheet.
7. Safety and regulatory information
Read the Safety Data Sheet before use. Safety Data Sheets and regulatory declarations are issued by our technical centre against the product and batch supplied, so they are sent on request rather than published. Request a Safety Data Sheet or declaration.
This Technical Data Sheet is published for on-screen reference. The information is given in good faith from laboratory and application experience and describes typical values; it is not a specification and does not replace a trial on your own substrate and line. Arctic Materials may revise this sheet without notice. Issue 2026.09.
Technical Data Sheets on this site are for on-screen viewing. For a controlled copy, write to tech@arcticmaterials.com.
Other grades in this range
Need a Safety Data Sheet, a regulatory declaration or a grade specified to your line? Contact our technical centre.