Arcstruct EP 240 MIO Intermediate Coat
Two-pack epoxy intermediate coat pigmented with micaceous iron oxide, whose plate-like particles align in the film and lengthen the path that moisture and ions take to reach the steel. It is the standard middle coat of a three-coat structural steel system and provides most of the total dry film thickness.
Grade Arcstruct EP 240 | Range Industrial and Infrastructure Coatings | Technology Two-pack solvent-borne epoxy with micaceous iron oxide pigmentation
Technical Data Sheet
Arcstruct EP 240
Issue 2026.09
1. Product description
Two-pack epoxy intermediate pigmented with micaceous iron oxide, whose plate-like particles align in the film and force moisture and ions to take a longer path to the steel. It is the standard middle coat in a three-coat structural steel system and provides most of the total dry film thickness. Sprays to a consistent build on complex fabrications and recoats cleanly under polyurethane or polysiloxane.
2. Features
- Lamellar micaceous iron oxide lengthens the diffusion path
- Delivers the specified dry build in one airless pass
- Consistent build on complex fabrications
- Recoats cleanly under polyurethane or polysiloxane topcoats
- Defined minimum and maximum overcoating interval
3. Recommended uses
Intermediate coat over Arcstruct PR primers in three-coat systems for structural steelwork, plant and equipment, and a build coat directly on blast-cleaned steel where a two-coat system is specified.
Substrates. Arcstruct PR primers, aged epoxy after abrasion, blast-cleaned steel where a two-coat system is specified
4. Typical properties
| Property | Typical value | Method |
|---|---|---|
| Technology | Two-pack solvent-borne epoxy with micaceous iron oxide pigmentation | Formulation |
| Finish | Matt, below 35 gloss units at 60 degrees, grey with the lustre of micaceous iron oxide | ISO 2813 |
| Pigmentation | Lamellar micaceous iron oxide that aligns parallel to the substrate | Formulation |
| Volume solids | 60 to 80 per cent | ISO 3233-1 |
| Density, mixed | 1.5 to 2.0 g/cm3 | ISO 2811-1 |
| Dry film thickness per coat | 100 to 200 micrometres | ISO 2808 |
| Adhesion, pull-off from blast-cleaned steel, complete system | Typically 5 to 15 MPa, cohesive failure preferred over adhesive | ISO 4624 or ASTM D4541 |
| Solvent resistance, fully cured film | 50 to 100 MEK double rubs without softening | ASTM D5402 |
| Neutral salt spray resistance, complete system | 240 to 1000 hours or more, set by the ISO 12944 corrosivity category and durability range, rated for blistering, rusting and undercutting | ISO 9227, rated to ISO 4628-2, -3 and -8 |
Typical values, not a specification. Values for each batch are given on its Certificate of Analysis.
5. Application
| Parameter | Guidance |
|---|---|
| Application method | Airless spray at a wet film that delivers the specified dry build in one pass; brush stripe coat on edges, welds and bolt heads before the main pass. |
| Substrate | Arcstruct PR primer, clean, dry and within its overcoating interval; aged epoxy abraded and cleaned; blast-cleaned steel to Sa 2.5 to ISO 8501-1 where a two-coat system is specified. |
| Mixing | Base and curing agent mixed completely at the stated ratio, given the stated induction time and used within the pot life, which shortens as temperature rises. |
| Film thickness | 100 to 200 micrometres dry per coat, wet film checked with a comb during application and dry film verified to ISO 2808. |
| Over inorganic zinc | First pass applied as a thin mist coat and allowed to flash off, then the full wet coat. |
| Conditions and overcoating | Substrate at least 3 degrees Celsius above the dew point during application and initial cure. Topcoat within the stated minimum and maximum overcoating interval; beyond the maximum interval the surface is abraded before topcoating. |
| Next coat | Arcstruct PU 260 Acrylic Polyurethane Topcoat or Arcstruct PU 420 Polysiloxane Topcoat. |
Process. Airless spray at a wet film that delivers the specified dry build in one pass, wet film checked with a comb and dry film verified to ISO 2808. Two-pack ambient cure, with a defined minimum and maximum overcoating interval. Exceeding the maximum interval requires abrasion before the topcoat. Over an inorganic zinc primer the first pass is applied as a mist coat
6. Storage and handling
Store in the original closed containers under cover, dry and out of direct sun, at 5 to 35 degrees Celsius; stir the base to redisperse any settlement before mixing. 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
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