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Asphalt Antifouling Paint - Technical Guide for Specialty

Asphalt Antifouling Paint (ACLH-304) technical guide: role in the coating system, detailed technical properties, surface preparation, mixing ratio, cure window, coverage per m², quality control and pricing. From Delshine Coatings.

Asphalt Antifouling Paint - Technical Guide for Specialty

Overview

The specialty range covers the coatings that do not fit neatly into a general category: marine systems for hulls and offshore structures, acid and alkali proofing linings, underwater curing coatings, antifouling, waterborne systems and the high-build primers built for severe corrosion service.

These are the products that solve a specific, difficult problem. A ballast tank coating has to survive immersion in seawater with a very high electrolyte conductivity. An antifouling has to poison the organisms that attach to a hull and stay effective at speed. An underwater curing coating has to harden on a submerged, cold, wet steel surface. Each needs its own chemistry, its own preparation standard and its own inspection regime.

For these systems the product data sheet is not guidance, it is the specification. Surface preparation, film thickness, curing conditions and the acceptance test are all part of the product's performance claim, and deviating from any of them voids it.

Asphalt Antifouling Paint: Ships

Product identification

The identifiers below are the ones printed on the drum and quoted on the purchase order. Always order and dispatch by code, because the grade and the zinc or temperature variant cannot be inferred from the trade name alone.

Product codeACLH-304
Trade nameAsphalt Antifouling Paint
CategorySpecialty coatings
System roleAntifouling coat - underwater hull protection
Manufacturer descriptionShips

Where this product is used

  • Ship hulls, ballast tanks, cargo holds and shipboard structures
  • Offshore platforms, risers, jackets and topside equipment
  • Acid and alkali resistant linings in chemical process plants
  • Underwater structures, pipelines and submerged repair work
  • Yacht hulls and underwater coatings
  • High-pressure pipeline internal linings
  • Waterborne systems for corrosion control in sensitive environments
  • Chemical resistant tank and bund interiors

How it works in the coating system

Antifouling coatings are applied to the submerged hull of a vessel to prevent marine organisms from attaching. The older copper-based systems work by leaching a biocide from the film; self-polishing types go further, shedding a biocide-loaded layer as the vessel moves through the water so the surface stays clean for the life of the coating.

Antifouling performance is governed as much by how the coating is applied as by what it is made of. Hull preparation, the minimum and maximum film thickness, the drying time before immersion and the vessel's service speed all affect how long it works.

Purpose in the system: Applied over a full anticorrosion system on the underwater hull, normally with a boot-topping band between antifouling and the topside coating.

Technical properties

The values below are the typical published range for this product family. The exact figures for your batch are confirmed on the batch certificate and the current technical data sheet.

Role in the coating systemSpecialised coating for a defined service environment
Volume solids50–100 %
Mixing ratio by volume4:1 or 5:1 by volume for two-pack grades; single component where stated
Typical dry film thickness60–300 µm per coat depending on the grade
Theoretical coverage3–12 m²/litre per coat
Application methodsAirless spray · conventional spray · brush · roller
Application temperature window5–40 °C, minimum 3 °C above dew point
Suitable substratesPrepared steel, concrete, tank internals and marine structures
Finish / appearanceFull colour range; matt or semi-gloss
Principal resistanceCorrosion, immersion, chemical attack, abrasion or fire, depending on the grade
UV resistanceVaries by grade — check the specific data sheet
Adhesion to prepared steel> 4 MPa pull-off on prepared steel
Salt spray performance> 2,000 h for the marine and offshore grades
Chemical resistanceVaries from general chemical resistance to acid and alkali proofing
Abrasion resistanceGood to excellent in the abrasion-resistant grades
Flash pointNot applicable (water-based) to 30 °C
Shelf life6–24 months unopened
Density1.05–1.60 g/cm³
Pack sizes1 kg–25 kg kits; 200 kg drums

Surface preparation

  1. Determine the exact service environment first — immersion, splash zone, atmospheric, chemical, temperature and the mechanical wear expected — and select the coating from the service environment, not from the generic product name.
  2. Abrasive blast steel to the standard stated in the product data sheet, which is normally Sa 2½ but may be Sa 3 or St 3 for specific products. Record the blast profile and anchor pattern.
  3. Test for soluble chlorides and wash with fresh water where contamination is likely, particularly on marine and offshore work.
  4. Carry out holiday detection on the completed coating and repair every defect before the coating is accepted.
  5. Confirm ambient conditions — substrate above the dew point by 3 °C, temperature above 10 °C and humidity below 80% — against the product's stated application window.
  6. For underwater or immersed work, use the specifically approved underwater curing grade and verify the substrate is clean of marine growth and loose scale.

Application procedure

The hull must be prepared to the standard stated in the product data sheet and be completely free of oil, grease, weld spatter and soluble salts.

Apply in a single controlled coat at the specified film thickness — antifouling is not designed to be built up in multiple layers.

Allow the coating to dry and cure for the full period stated before the vessel is immersed. Immersing early will damage the film and lose the biocide release mechanism.

Mixing, ratio and induction time

Mix thoroughly until the pigment is fully dispersed and the mix is uniform in colour and density. Some grades need a long induction to wet out the dispersant properly.

Cure, recoat window and service readiness

Touch dry in 4 to 8 hours, with an immersion allowed only after the full drying period stated on the data sheet — typically 12 to 24 hours, longer in cool or humid conditions.

Coverage and thickness calculation

Specified by minimum dry film thickness rather than coverage per litre, and the two must both be met. Under-film is the most common antifouling failure and there is no way to correct it once the vessel is in the water.

Technical note. Coverage (m²/litre) = (volume solids × 10) / DFT (µm)

Worked example

Specified DFT150 µm
Volume solids70 %
Theoretical coverage4.67 m²/litre
Total for the area100 m² → 466.7 litres

Advantages

  • Products engineered for severe service — ballast tanks, chemical immersion, splash zones and underwater repair.
  • Certification available for ship classification and potable water where the grade requires it.
  • Specialised chemistry for genuinely difficult problems such as underwater curing and static conductivity.
  • High-build formulations that deliver long service life in corrosive atmospheres with fewer coats.
  • Waterborne options for sites with strict VOC limits or occupational exposure controls.
  • Full coating systems available from a single manufacturer, which removes compatibility risk between coats.

Limitations and precautions

  • Each product has a narrow, defined application window and is not interchangeable with a superficially similar product.
  • Failure to follow the specified preparation, film thickness and curing conditions voids the performance claim.
  • Marine and offshore work requires access, weather windows and specialist application equipment.
  • Some specialty grades are expensive and the volumes required may not justify the cost on small projects.
  • Chemical resistance ratings assume the stated concentration and temperature; exceeding either invalidates the selection.

Storage and shelf life

  • Store component A and B in their original sealed containers in a cool, dry, ventilated store between 5 °C and 30 °C.
  • Protect from freezing and direct sunlight, and keep containers tightly closed.
  • Do not store two-pack components next to strong oxidisers or solvents.
  • Rotate stock first-in-first-out and observe the labelled shelf life.

Safety, PPE and ventilation

  • Use full respiratory protection, chemical-resistant gloves, goggles and protective clothing for all application work.
  • Ensure excellent ventilation; offshore and confined-space applications require atmospheric testing before entry.
  • Keep ignition sources away from solvent-borne grades.
  • Follow the product's specific safety data sheet — marine and antifouling grades may carry additional handling requirements.
  • Collect all waste and dispose of it through a licensed contractor.

Quality control and inspection

  • Record the hull preparation standard before coating.
  • Measure the dry film thickness at multiple points during application.
  • Confirm the drying time before immersion and record it against the vessel's actual docking time.

Pricing and how to order

Delshine quotes this product per square metre at a specified dry film thickness, or per drum/litre depending on the project. The material cost is usually the smallest part of the installed cost — surface preparation, access and application labour dominate. Send us the substrate, the service conditions and the required DFT and our technical team will return a full system recommendation with a firm price.

Specialty and marine coatings are quoted per square metre at a specified dry film thickness, normally as a complete system. On offshore and marine work, the preparation and access costs are frequently larger than the coating cost itself, so always specify preparation, holiday testing and inspection explicitly in the contract scope.

Frequently asked questions

The questions below are the ones our technical team is asked most often about this product family.

What is underwater curing coating and when is it used?

Underwater curing coatings are formulated to harden on a submerged, cold, wet steel surface where conventional epoxy cannot cure because it needs oxygen and warmth. They are used for offshore structural repair, pipeline repair clamps and any situation where the steel cannot be dried. The underwater curing anticorrosive coating in the Delshine range is designed for exactly this application.

What is antifouling paint and how does it work?

Antifouling prevents marine organisms — barnacles, algae, molluscs — from attaching to a hull underwater. Traditional copper-based antifouling works by leaching biocides from the film; self-polishing antifouling goes further and sheds a biocide-containing layer as the vessel moves, keeping the surface clean for the life of the coating. Application, thickness and hull preparation all follow strict specification.

Which coating should I use in a ballast tank?

A ballast tank coating must resist seawater immersion with a very aggressive electrolyte, and it must be able to withstand movement and vibration of the vessel. The modified epoxy ballast tank anticorrosive coating in the range is specified for this service, in grey, with a defined preparation standard and acceptance test.

What is a static-conductive coating?

It is a coating that conducts electricity to earth at a controlled rate, dissipating static charge that would otherwise build on equipment and create a spark. It is used in fuel tank interiors, pharmaceutical cleanrooms and areas handling flammable materials. Unlike an antistatic coating, which limits charge build-up, a static-conductive coating has a defined low surface resistance and requires an earth connection to work.

How do I select the right coating for chemical immersion?

List the chemicals, their concentrations and the operating temperature, then select a coating whose published resistance table covers all three. Phenolic epoxy is the standard answer for strong acids, vinyl ester for a broad acid and alkali range, and epoxy coal tar for petroleum products. If the combination is not covered by a published table, ask the manufacturer to test — do not assume compatibility.

Can a specialty coating be applied in the field?

Many can, provided the preparation, ambient conditions and film thickness match the specification. Field application is routine for offshore maintenance, provided the surface is prepared to the required standard and the application is inspected. Where the product's certification depends on controlled factory application, check the certificate before specifying a field-applied system.

These products are normally used in the same system as the product described above.

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