What is ALEXSEAL Interior Primer 178 and why choose it?
ALEXSEAL Interior Primer 178 is a professional-grade, two-component epoxy primer designed for fast-drying corrosion protection on interior metal surfaces. Formulated with low odour and high mechanical resistance after curing, it provides a solid epoxy base that can be left uncoated in non-visible areas or quickly overcoated with ALEXSEAL N-Series Interior Topcoat 578. The product is approved under IMO Resolution MSC.307 (88) – FTP Code 2010 as a marine paint with low flame-spread characteristics, making it suitable for demanding marine interiors where safety and performance are critical.
Main features
- Two-component epoxy system: epoxy base plus converter for a durable, chemically and mechanically resistant primer film.
- Fast drying: dust-free from approximately 20–45 minutes and tape-dry from 12–24 hours depending on temperature (15–25 °C).
- Low odour formulation: improves working comfort in enclosed interior spaces.
- Excellent corrosion protection: protects steel and aluminium substrates and promotes adhesion for subsequent interior topcoats.
- High solids content: approximately 68% solids (catalyzed without reduction) for efficient film build.
- Can be used without topcoat: suitable as a stand-alone coating in areas where aesthetics are not critical.
- Marine certification: approved as a low flame-spread marine paint according to IMO Resolution MSC.307 (88) – FTP Code 2010.
- Available colours: White and Light Gray for bright, practical interior surfaces.
- Professional-use formulation: designed for industrial serial painting and application with professional spray, brush and roller equipment.
Technical characteristics
Product composition and appearance
- Type: Epoxy-based, two-component interior primer.
- Base materials: White or Light Gray epoxy base (P1780 White, P1783 Light Gray).
- Converter: ALEXSEAL Interior Primer Converter C1787 (clear).
- Reducer: ALEXSEAL Interior Primer Reducer Spray & Brush R1789.
- Physical state: Liquid.
- Flash point: Approx. 26 °C (ISO 13736).
- Density: Approx. 1.75 g/cm³ at 20 °C.
- VOC content: Approx. 23.55% (about 412 g/l).
Coverage and film build
- Solids (catalyzed, without reduction): 68%.
- Recommended dry film thickness (DFT): 150 µm (5 mils) for coverage table; 200–250 µm (8–10 mils) when applying two full coats by spray as specified in section 8.
Theoretical coverage at 150 µm (5 mils) DFT:
- 4.8 m²/litre (17 m²/gal), approx. 183 sq. ft./gal.
Practical coverage at 150 µm (5 mils) DFT (approximate):
- Conventional air spray: 3.0 m²/l (11.0 m²/gal), about 120 sq. ft./gal.
- HVLP air spray: 3.2 m²/l (11.8 m²/gal), about 130 sq. ft./gal.
- Airless equipment: 3.6 m²/l (13.2 m²/gal), about 140 sq. ft./gal.
- Brush/roller: 4.0 m²/l (15.0 m²/gal), about 165 sq. ft./gal.
Mixing ratios
For spray application:
- 4 parts by volume P178x Interior Primer Base 178.
- 1 part by volume C1787 Interior Primer Converter.
- Approx. 30% reduction (vol.) with R1789 Interior Primer Reducer Spray & Brush.
- Example: 4 : 1 : 1½ = 30% reduction.
For brush and roller application:
- 4 parts by volume P178x Interior Primer Base 178.
- 1 part by volume C1787 Interior Primer Converter.
- Minimum 15% reduction (vol.) with R1789 Interior Primer Reducer Spray & Brush.
- Example: 4 : 1 : ¾ = 15% reduction.
The exact reducer amount may be adjusted to suit application conditions. Mixed material must be filtered before application.
Application parameters
- Viscosity for spray: DIN 4 cup (4 mm) ≈ 35 s at 30% reduction.
- Viscosity for roll: DIN 4 cup (4 mm) ≈ 70 s at 15% reduction.
- Nozzle size – gravity gun: 1.4–1.7 mm (0.055–0.067 in), conventional and HVLP.
- Nozzle size – siphon cup: 1.6 mm (0.063 in), conventional and HVLP.
- Fluid nozzle size – pressure pot: 1.2–1.4 mm (0.047–0.055 in), conventional and HVLP.
- Atomizing pressure: 3.0–4.0 bar (44–58 psi) for conventional & HVLP.
- Pot pressure (pressure pot systems): 1.0–2.0 bar (15 psi).
Spray application recommendation:
- Apply 2 coats to achieve a total wet film thickness (WFT) of 400–500 µm (8–10 mils).
- This results in a dry film thickness (DFT) of approximately 200–250 µm (8–10 mils).
Pot life and drying times
Optimal application environment: 15–30 °C (60–85 °F) and 20–70% relative humidity. Minimum object temperature during drying is 15 °C (68 °F); ideal temperature is 25 °C (77 °F). Minimum application conditions should be 3 °C (5.4 °F) above the dew point.
| Condition |
15 °C (60 °F) |
20 °C (68 °F) |
25 °C (77 °F) |
| Pot life (approx.) |
6 hours |
4 hours |
3 hours |
| Dust free |
45 min |
30 min |
20 min |
| Tape dry |
24 h |
16 h |
12 h |
| Fully cured |
10 days |
7 days |
5 days |
Recoating intervals
- Recoating by spraying with another coat of Interior Primer 178:
- 15 °C: minimum 3 hours; maximum 3 months.
- 20 °C: minimum 2 hours; maximum 3 months.
- 25 °C: minimum 1.5 hours; maximum 3 months.
- Recoating by rolling with another coat of Interior Primer 178:
- 15 °C: minimum 6 hours; maximum 3 months.
- 20 °C: minimum 4 hours; maximum 3 months.
- 25 °C: minimum 3 hours; maximum 3 months.
- Overcoating with other products (including ALEXSEAL N-Series Interior Topcoat 578):
- 15 °C: minimum 12 hours; maximum 14 days.
- 20 °C: minimum 8 hours; maximum 14 days.
- 25 °C: minimum 6 hours; maximum 14 days.
Substrate preparation
- Substrate must be clean, dry and free from dust, grease, oil and any other contamination.
- Apply Interior Primer 178 directly to properly cleaned and prepared substrates, ideally within 6 hours of preparation.
Recommended surface preparation:
- Steel: Sandblast to near white metal SA 2.5 (SSPC–SP10-85) or grind with 36–40 grit to achieve a profile of 50–100 µm (2–4 mils).
- Aluminium: Sandblast or grind with 36–60 grit to bright, clean aluminium with a 50–100 µm (2–4 mils) profile.
- Gelcoat (80–100 grit) and fiberglass resin (36–60 grit): surfaces should be ground before the interior topcoat application.
Applications and use cases
- Marine interiors: bulkheads, structural steel and aluminium components inside vessels where low flame-spread characteristics are required.
- Industrial interior metalwork: corrosion protection and adhesion promotion on steel and aluminium inside machinery rooms, enclosures and structural frames.
- Interior areas not requiring decorative finishes: can be left without a topcoat where appearance is secondary but long-term protection is essential.
- As a base for ALEXSEAL N-Series Interior Topcoat 578: provides an optimised epoxy underlayer for high-performance interior finishing systems.
FAQ
1. What substrates can ALEXSEAL Interior Primer 178 be applied to?
The primer is designed for steel and aluminium substrates. Gelcoat and fiberglass resin surfaces should be ground prior to applying the interior topcoat system.
2. Can this primer be left without a topcoat?
Yes. After full curing, Interior Primer 178 can be left uncoated in areas where there are no specific aesthetic requirements.
3. Which topcoat is recommended over this primer?
The system is designed to be overcoated with ALEXSEAL N-Series Interior Topcoat 578 within the stated recoating window, but other compatible products may also be used according to the technical data.
4. How many coats are recommended?
For spray application, apply 2 coats to achieve 400–500 µm (8–10 mils) wet film thickness, resulting in 200–250 µm (8–10 mils) dry film thickness.
5. What is the pot life of the mixed product?
Depending on temperature, pot life is approximately 6 hours at 15 °C, 4 hours at 20 °C and 3 hours at 25 °C.
6. Is this product suitable for use in confined interior spaces?
The primer has low odour and is specifically developed for interior use, but adequate ventilation and appropriate personal protective equipment are still required.
7. What is the recommended environmental range for application?
Apply between 15 and 30 °C, with 20–70% relative humidity, ensuring the substrate temperature remains at least 3 °C above the dew point.
8. Does ALEXSEAL Interior Primer 178 offer fire-related performance?
Yes. It is approved by IMO Resolution MSC.307 (88) – FTP Code 2010 as a marine paint with low flame-spread characteristics.
9. How should the surface be prepared before application?
Steel and aluminium should be sandblasted or ground to the specified profiles, and all substrates must be clean, dry and free of contaminants. Gelcoat and fiberglass resin surfaces should be ground prior to subsequent interior topcoat application.
Section 14 – Transport information
ALEXSEAL Interior Primer 178 is classified as a flammable liquid for transport.
- UN number / ID number: UN 1263.
- Proper shipping name: PAINT.
- Transport hazard class: Class 3 (Flammable liquids).
- Packing group: III.
- ADR (road transport):
- Classification code: F1.
- Hazard identification number: 30.
- Labels: 3.
- Tunnel restriction code: (D/E).
- Environmentally hazardous: no.
- Small receptacles (< 450 l) within user premises may fall under specific ADR exemptions.
- IMDG (sea transport):
- Class: 3.
- Packing group: III.
- Labels: 3.
- EmS code: F-E, S-E.
- Marine pollutant: no.
- Receptacles with less than 450 litres capacity may be exempt from certain IMDG provisions (4.1, 5.2 and 6.1).
- IATA (air transport):
- Class: 3.
- Packing group: III.
- Cargo aircraft packing instruction: 366.
- Passenger aircraft packing instruction: 355 (LQ: Y344).
- Labels: Flammable Liquids.
If transported within the user’s premises, always move the product in closed, upright and secure containers. Ensure personnel handling the containers are familiar with emergency procedures in case of incident or spillage.
Section 8 – Personal protective measures
When handling ALEXSEAL Interior Primer 178, follow the recommendations of the Safety Data Sheet for safe, professional use.
Engineering controls
- Provide adequate local exhaust and general ventilation to keep solvent vapour and spray mist below occupational exposure limits.
- In spray booths or enclosed spaces, ventilation alone may not suffice; additional respiratory protection may be necessary until solvent vapour and particulates fall below exposure limits.
Eye and face protection
- Wear safety goggles designed to protect against solvent splashes.
- In high-exposure scenarios, use additional face protection as required.
Hand protection
- Use chemical-resistant protective gloves compliant with EN 374.
- Recommended materials for splash protection: nitrile rubber or neoprene.
- Minimum glove thickness: > 0.4 mm.
- Recommended breakthrough time: > 480 minutes.
- Inspect gloves before use to confirm suitability for the specific workplace conditions and replace immediately if damaged or worn.
- Wash contaminated skin promptly and consider using protective skin creams as preventive care.
Skin and body protection
- Wear suitable protective clothing adapted to the potential for explosive atmospheres and solvent exposure.
- Avoid product contact with skin and clothing; remove contaminated clothing immediately.
Respiratory protection
- If solvent vapour concentrations exceed occupational exposure limits, use appropriate respiratory protection.
- Use an approved half-mask respirator with suitable cartridges or an air-fed breathing apparatus.
- For dry grinding, torch cutting or welding on coated surfaces, implement wet methods or effective exhaust hoods; if not possible, wear suitable respiratory protection.
General hygiene measures
- Do not eat, drink or smoke while using the product.
- Wash hands and exposed skin thoroughly after handling.
- Avoid inhalation of sanding dust, spray mist and solvent vapours.
*Contenido generado por IA
