Arcshield HT 270 Heat-Resistant Silicone Coating
A single-pack silicone or silicone acrylic coating pigmented with aluminium or heat-stable pigment for hot, dry, uninsulated steel. The film air dries to a handleable state and develops its final hardness and heat resistance on first heating in service.
Grade Arcshield HT 270 | Range Protective and Marine Coatings | Technology Single-pack silicone or silicone acrylic, aluminium or heat-stable pigment, solvent-borne
Technical Data Sheet
Arcshield HT 270
Issue 2026.09
1. Product description
A single-pack silicone or silicone acrylic coating pigmented with aluminium or heat-stable pigment, for exhaust stacks, flare lines, steam and process pipework, boiler casings and other hot, dry, uninsulated steel. The film air dries to a handleable state and develops its final hardness and heat resistance on first heating in service, so the cure schedule is part of the specification. It is suited to steel that runs hot and stays dry, and it is not suited to insulated lines or to wet cyclic exposure.
2. Features
- Aluminium-pigmented silicone for continuous dry service up to about 540 °C
- Air dries to handle; final cure on first heating to service temperature
- Applied in two thin coats to avoid cracking on heating
- Over blast-cleaned steel or an inorganic zinc silicate primer
3. Recommended uses
Exhaust stacks, flare lines, steam and process pipework, boiler casings and other steel that runs hot and stays dry. It is not suited to insulated lines or wet cyclic exposure.
Substrates. Abrasive blast cleaned carbon steel and stainless steel, and over an inorganic zinc silicate primer where the system requires one. It is not applied over organic anti-corrosive primers that will degrade at the service temperature.
4. Typical properties
| Property | Typical value | Method |
|---|---|---|
| Technology | Single-pack silicone or silicone acrylic, aluminium or heat-stable pigment, solvent-borne | Formulation |
| Appearance | Aluminium or coloured film; colour range limited by pigment stability at temperature | Visual, supplier protocol |
| Dry heat resistance | Aluminium-pigmented silicone: continuous dry service up to about 540 °C with short excursions towards 600 °C; coloured and silicone acrylic grades at lower limits stated per grade | ASTM D2485 |
| Volume solids | Typically 25 to 50 per cent | ISO 3233-1 |
| Dry film thickness per coat | Typically 20 to 40 µm, two coats | ISO 2808 |
| Surface drying | Typically 0.5 to 2 h at 20 °C | ISO 9117-3 |
| Cure | Final hardness and heat resistance develop on first heating, by ramping the asset to service temperature to the stated schedule | Customer or supplier protocol |
| Service limitation | Hot, dry, uninsulated steel; not for insulated lines or wet cyclic exposure | Customer or supplier protocol |
Typical values, not a specification. Values for each batch are given on its Certificate of Analysis.
5. Application
| Parameter | Guidance |
|---|---|
| Method | Airless or conventional spray at low film build, because thick films of silicone crack on heating. |
| Surface preparation | Carbon steel abrasive blast cleaned to Sa 2½ (ISO 8501-1), profile typically 30 to 50 µm Rz (ISO 8503-2); stainless steel sweep blasted to a uniform angular profile with a non-metallic, iron-free and chloride-free abrasive; or over an inorganic zinc silicate primer where the system requires one. Not over organic anti-corrosive primers that degrade at the service temperature. |
| Thinning | Thinner as stated on the product data, added only as needed for the application method. |
| Applied film thickness | Two thin coats, typically 20 to 40 µm dry each, to the specified total, verified to ISO 2808. |
| Application conditions | Steel temperature at least 3 °C above dew point (ISO 8502-4) and relative humidity normally 85 per cent or less during application and cure. |
| Cure schedule | Air dry, then cure by ramping the asset to service temperature according to the stated schedule. |
Process. Airless or conventional spray at low film build, because thick films of silicone crack on heating. Two thin coats to the specified total thickness, air dry, then cure by ramping the asset to service temperature according to the stated schedule. Colour range is limited by the pigment stability at temperature.
6. Storage and handling
Store in the original closed containers in a dry, covered store, typically between 5 and 35 °C and out of direct sunlight. 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.