FAIRING COMPOUND 242

What is ALEXSEAL FAIRING COMPOUND 242 and why choose it?

ALEXSEAL Fairing Compound 242 is a solvent-free, epoxy-based, lightweight filler designed for professional yacht building and repair. It offers excellent application, sanding and anti-sagging properties, creating a smooth and stable surface that can be re-coated with other ALEXSEAL Yacht Coating products. Suitable for use above and below the waterline (when sealed with ALEXSEAL Finish Primer 442 below the waterline), it is engineered to be easy to mix, apply and sand, while delivering high-quality fairing results on properly prepared substrates.

Main features

• Solvent-free epoxy filler: 100% catalyzed volume solids without reduction.
• Lightweight fairing compound: Ideal for filling and fairing yacht hulls and superstructures.
• Excellent workability: Optimized for easy mixing, troweling and feathering with minimal sagging.
• Good sanding characteristics: Designed for block sanding with 36–120 grit to achieve a fair, smooth surface.
• Re-coatable system: Cured film provides an excellent base for subsequent ALEXSEAL primers and topcoats.
• Above and below waterline use: Can be applied on all appropriately prepared surfaces; below waterline applications must be sealed with ALEXSEAL Finish Primer 442.
• Clear color coding for mixing: Base and converters are different colors to visually control mix homogeneity.
• Professional-grade product: Intended for professional use only, in controlled conditions.

Technical specifications

Product identification

• Product name: ALEXSEAL Fairing Compound 242
• Product code: P2420
• Type: Epoxy-based, solvent-free, lightweight fairing compound

Colors

• Color of mixture: Green-gray
• Standard Base: Light ivory
• Standard Converter: Green
• Fast Converter: Red

Coverage

Volume solids (catalyzed, without reduction): 100 %

Coverage depends on filling depth and total surface area. Theoretical and practical coverage values (base + converter):

• Theoretical coverage: 1 m²/L (3.8 m²/gal, 41 sq ft/gal) at 1 mm (1/25”) dry film thickness.
• Practical coverage at average thickness:
  • 0.15 m²/L (0.6 m²/gal, 6.4 sq ft/gal) at 6 mm (1/4”).
  • 0.11 m²/L (0.44 m²/gal, 4.8 sq ft/gal) at 8 mm (3/8”).
  • 0.07 m²/L (0.29 m²/gal, 3.2 sq ft/gal) at 10 mm (1/2”).

Substrate preparation

• General: Substrate must be clean, dry and free of dust, grease, oil and other contamination.
• Surface profile: Grind and/or blast with 36–60 grit prior to priming to ensure adhesion.
  • Full fairing systems: heavily abraded substrate recommended.
  • Thin fairing systems (< 3 mm / approx. 1/8–0.012 in): less aggressive profile sufficient.
• Metal substrates: Prime with ALEXSEAL Protective Primer 161 for optimum mechanical and corrosion resistance. Fairing Compound 242 may be applied directly over Protective Primer 161 without sanding for up to 6 months.
• GRP substrates: Apply ALEXSEAL Super Build 302, Finish Primer 442 or Protective Primer 161 over the properly prepared surface. All ALEXSEAL Primers (except 161) must be sanded with 60–80 grit after overnight dry before application of Fairing Compound 242.
• Other substrates (e.g. epoxy resins): Consult your ALEXSEAL representative.

Trade names and packaging

• P2420: ALEXSEAL Fairing Compound 242 Base – ½ Gal, 2 Gal
• C2427: ALEXSEAL Fairing Compound 242 Converter – ½ Gal, 2 Gal
• C2425: ALEXSEAL Fairing Compound 242 Converter Fast – ½ Gal, 2 Gal

Mixing ratio

• By volume: 1 : 1 (Base : Converter)
• By weight: 10 : 6 (Base : Converter)
• Reduction: Product must not be reduced; solvent-free application.

Application

• Application tools: Trowels, spatulas, straight edge materials.
• Mixing control: Base and converter are different colors; after thorough mixing, the filler must show a homogeneous color. Incomplete mixing can result in improper cure.
• Mixing method: Mechanically with slow-turning dough mixers or manually. Drill mixers must not be used. Avoid entrapping air bubbles.
• Application technique: Apply in thin layers with spatula or trowel, working up to the required thickness and then pulling off excess with a straight edge to minimize air pockets.
• Equipment cleaning: R4042 ALEXSEAL Epoxy Primer Reducer.
• Sanding: Block sand with 36–120 grit. Finishing with 80 grit or finer helps prevent sand scratch print through in the final coating system.

Pot life and drying

Optimal application environment: 15–30 °C (60–85 °F), 40–80 % RH.

Use Fast Converter below 15 °C (60 °F). Do not use the product below 10 °C (50 °F) or above 40 °C (104 °F). Actual drying and recoat times depend on surface temperature, air flow, sunlight exposure and applied film thickness.

Recoating

• Over itself: Follow minimum dry-to-sand times before recoating. Scratch sanding with 36–60 grit is recommended to ensure intercoat adhesion.
• With other ALEXSEAL products: Overcoating with 302, 303, 328 or 442 is possible after the minimum time and after block sanding with 36–120 grit. Finishing with 80 grit or finer helps avoid visible sand scratches in the final finish.

Applications and use cases

• Yacht hull fairing: Filling and fairing of metal or GRP hulls prior to epoxy primers and topcoats.
• Superstructure smoothing: Creating an even surface on decks, cabins and superstructures before high-build primers and finishing systems.
• Localized repair work: Filling dents, irregularities and minor defects on previously primed areas within the ALEXSEAL system.
• Below-waterline fairing: Fairing of underwater hull sections when subsequently sealed with ALEXSEAL Finish Primer 442.
• Professional refit projects: Use in professional yards and workshops where controlled mixing, application and sanding are standard practice.

FAQ

1. Can ALEXSEAL Fairing Compound 242 be used below the waterline?

Yes. It can be used above and below the waterline, but below-waterline applications must be sealed with ALEXSEAL Finish Primer 442.

2. Do I need to reduce or thin the product before application?

No. ALEXSEAL Fairing Compound 242 is solvent-free and must not be reduced.

3. Which substrates are suitable?

It is suitable for appropriately prepared and primed metal and GRP substrates within the ALEXSEAL system. For other substrates such as epoxy resins, contact your ALEXSEAL representative.

4. How should the surface be prepared for best adhesion?

The substrate should be clean, dry and free from contamination, then ground or blasted with 36–60 grit before priming. Primers (except 161) must be sanded with 60–80 grit after overnight drying before applying the fairing compound.

5. What is the recommended pot life?

With standard converter C2427, pot life ranges from about 1 hour at 15 °C (60 °F) to 30 minutes at 30 °C (85 °F).

6. How soon can I sand the fairing compound?

Dry-to-sand time varies with temperature, from approximately 36 hours at 15 °C (60 °F) to 12 hours at 30 °C (85 °F).

7. Which grits should I use for sanding?

Block sand with 36–120 grit. Finishing with 80 grit or finer helps prevent sand scratch print through in the final coating.

8. What cleaning solvent is recommended for tools and equipment?

Use R4042 ALEXSEAL Epoxy Primer Reducer for cleaning application equipment.

9. Can I recoat Fairing Compound 242 with other ALEXSEAL products?

Yes. After minimum dry and proper sanding (36–120 grit), it can be overcoated with ALEXSEAL products including 302, 303, 328 and 442.

10. Is this product intended for consumer or professional use?

The product is specified as Professional Use Only.

Section 14 – Transport information

• UN number: UN 3077
• UN proper shipping name (ADR / IMDG / IATA): ENVIRONMENTALLY HAZARDOUS SUBSTANCE, SOLID, N.O.S. (reaction product: bisphenol-A-(epichlorhydrin) and epoxy resin (number average molecular weight ≤ 700), REACTION PRODUCT:BISPHENOLF-(EPICHLORHYDRIN), EPOXY RESIN)
• Transport hazard class: 9 (ADR, IMDG, IATA)
• Packing group: III (ADR, IMDG, IATA)
• ADR classification code: M7
• ADR hazard identification number: 90
• Labels: 9 (Miscellaneous dangerous substances and articles)
• ADR tunnel restriction code: (E)
• IMDG EmS code: F-A, S-F
• IATA packing instructions: 956 (cargo aircraft and passenger aircraft)
• Environmentally hazardous / Marine pollutant: Yes
• Bulk transport (MARPOL/IBC): Not applicable for product as supplied.

Section 8 – Personal protective measures

Exposure controls

• Engineering controls: Provide adequate ventilation using local exhaust and good general extraction.

Personal protective equipment (PPE)

• Eye protection: Wear safety goggles to protect against splashes.
• Hand protection:
  • Use chemical-resistant protective gloves compliant with EN 374.
  • Recommended for short-term contact: nitrile rubber or neoprene.
  • Minimum material thickness: > 0.4 mm; breakthrough time: > 480 minutes.
  • Check gloves for suitability and damage before use and replace when worn.
• Skin and body protection: Wear standard chemical-industry work clothing. Wash skin after contact. Preventive skin protection (skin protection cream) is recommended.
• Respiratory protection: Normally not required, but avoid breathing vapours. Avoid inhalation of dust from sanding, particulates and spray mist arising from application.

General protective measures

• Do not eat, drink or smoke while working with the product.
• Avoid contact with skin, eyes and clothing.
• Avoid release to the environment; do not allow product to enter drains or watercourses.