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Application Guide - Above Waterline Application Systems

Surface Preparation and Priming - Aluminum

This section contains preparation methods for two types of aluminum surfaces:

  1. Non-anodized parts

    • Grinding

    • Blasting

    • Blister Repair

  2. Anodized parts

These systems are designed to provide maximum performance of the coating system with allowances and adjustments for facility and engineering limitations.

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In these situations blasting or grinding the aluminum to remove the oxidization, creating clean, bright, shiny aluminum with an appropriate profile will provide excellent performance. The key here is priming the surface immediately after completing the blast or grind before the aluminum can re-oxidize.

The system for blister repairs on previously painted surfaces specifically takes into account difficulties in obtaining perfect surface preparation in these situations.

Non-Anodized Parts


Grinding

  1. Thoroughly clean and degrease the surface. Use commercial detergents, steam cleaners or pressure washers. Be sure all detergent residue is rinsed from the surface. Use Awlgrip Wipe-Down Solvent (NA/AP: Awlprep Plus T0115; EU: Surface Cleaner T0340) as a final wipe down of the surface.

    Important

    Plan your work schedule carefully! Any area which is ground or blasted must be primed during the same work shift. Preferably within 4 hours.

  2. Grind with 36 grit disc to bright, clean aluminum. The metal must be bright silver and completely free of gray oxidation. The surface profile must be a 2–3 mils profile (50–75 microns).
  3. Blow off the surface thoroughly with clean, dry compressed air or vacuum to remove all grind/sanding residue and any dust or dirt. Use a brush or broom if necessary.

    Caution

    Do not use rags to clean this surface. The sharp metal will snag fibers from the rags. These fibers can act as wicks for moisture or other contamination to enter the paint film. This can lead to premature failure of the Awlgrip Coating System.

    To hold your surface preparation and prevent the need to repeat this work, the substrate should now be primed as detailed below.

    Important

    Products in Step 5 must be applied within maximum 72 hours of the completion of Step 4 (preferably within the same work shift).

  4. Prime the prepared aluminum with Max Cor CF. Spray apply 1 coat of Max Cor CF in one full wet coat to approximately 0.8–1.4 mils (20–34 microns) wet film thickness to achieve 0.6–1.0 mil (15–25 microns) dry film thickness.

    Important

    Allow to cure for a minimum of 17 hours.

    Caution

    Do not use a roller to apply the primer in Step 4. See previous caution regarding wicks.

  5. Apply Hullgard Extra by roller or spray. For spray application apply 9 mils (220 microns) wet film thickness to achieve 4 mils (100 microns) dry film thickness. Allow a minimum drying time of 3 hours at 68°F (20ºC) before proceeding.

Roller application will require at least two coats to achieve 4 mils (100 microns) dry film thickness. Allow a drying time of 3 hours at 68°F (20ºC) between coats.

Depending upon the conditions it may be possible to proceed to filling and surfacing without the need for sanding (See Fairing and Surfacing section for detailed information). Please consult product datasheet for further details.

Hotworks on the aluminum will damage the Hullgard Extra primer, please check with your local Technical Sales Representative for the appropriate repair guidelines.

Blasting

  1. Thoroughly clean and degrease the surface. Use commercial detergents, steam cleaners or pressure washers. Be sure all detergent residue is rinsed from the surface. Use Awlgrip Wipe-Down Solvent (NA/AP: Awlprep Plus T0115; EU: Surface Cleaner T0340) as a final wipe down of the surface.

    Important

    Plan your work schedule carefully! Any area which is ground or blasted must be primed during the same work shift. Preferably within 4 hours.

  2. Grit blast to bright, clean aluminum with a 2–3 mils (50–75 microns) profile. If profile is particularly jagged, grind to remove "spikes," providing a more uniform surface.
  3. Blow off the surface thoroughly with clean, dry compressed air or vacuum to remove all blast/grind/sanding residue and any dust or dirt. Use a brush or broom if necessary.

    Caution

    Do not use rags to clean this surface. The sharp metal will snag fibers from the rags. These fibers can act as wicks for moisture or other contamination to enter the paint film. This can lead to premature failure of the Awlgrip Coating System.

    To hold your surface preparation and prevent the need to repeat this work, the substrate should now be primed as detailed below.

    Important

    Products in Step 5 must be applied within 72 hours of the completion of Step 4 or the surface will have to be sanded and Step 4 repeated.

  4. Prime the prepared aluminum with Max Cor CF. Spray apply Max Cor CF in one full wet coat to approximately 0.8–1.4 mils (20–34 microns) wet film thickness to achieve 0.6–1.0 mils (15–25 microns) dry film thickness.

    Important

    Allow to cure for a minimum of 17 hours.

    Caution

    Do not use a roller to apply the primer in Step 4. See previous caution regarding wicks.

  5. Apply Hullgard Extra by roller or spray. For spray application apply 9 mils (220 microns) wet film thickness to achieve 4 mils (100 microns) dry film thickness. Allow a minimum drying time of 3 hours at 68°F (20ºC) before proceeding.

Roller application will require at least two coats to achieve 4 mils (100 microns) dry film thickness. Allow a drying time of 3 hours at 68°F (20ºC) between coats.

Depending upon the conditions it may be possible to proceed to filling and surfacing without the need for sanding (See Fairing and Surfacing section for detailed information).

Please consult product datasheet for further details.


Alternative Aluminum Systems

In some circumstances a full anti-corrosive/fairing system may not be required (e.g. window frames, parts etc). In such instances there are two alternative options for coating the suitably prepared aluminum — A Fast Drying Topcoat System or a Build System. Below details the surface preparation for both systems.

Fast Drying Topcoat System

  1. Thoroughly clean and degrease the surface. Use commercial detergents, steam cleaners or pressure washers. Be sure all detergent residue is rinsed from the surface. Use Awlgrip Wipe-Down Solvent (NA/AP: Awlprep Plus T0115; EU: Surface Cleaner T0340) as a final wipe down of the surface.
  2. Sand with 180 - 220 grit paper.
  3. Blow off the surface thoroughly with clean, dry compressed air or vacuum to remove all blast/grind/sanding residue and any dust or dirt. Use a brush or broom if necessary.
  4. Apply by air atomized spray 1 coat of Wash Primer CF at 2 mils (50 microns) wet film thickness giving a dry film thickness of 0.25 mils (6 microns). Several passes are required with the spray gun for a good surface. The first pass should be relatively slow (5–10cm / 2–4 inches per second). This pass is to obtain basic coverage.

Following sanding, if necessary, surface is now ready for topcoat application.

Build System

  1. Grind the substrate as per steps 1–3, p23 or blast the substrate as per steps 1–3, p24.
  2. Apply by air atomized spray 1 coat of Wash Primer CF at 2 mils (50 microns) wet film thickness giving a dry film thickness of 0.25 mils (6 microns). Several passes are required with the spray gun for a good surface. The first pass should be relatively slow (5–10cm / 2–4 inches per second). This pass is to obtain basic coverage.

Following sanding, if necessary, surface is now ready for final prime and topcoat application.

Important

While the build system will be touch dry at 24 hours at 77°F (25°C) following topcoat application, it’s important for the ‘controlled fusion’ to fully activate and through dry. No assembly, stacking or drilling should take place prior to 2 weeks at 77°F (25°C), or 3 weeks at 55°F (13°C).

This section is for repairing corrosion–related blistering on both heavily faired surfaces and surfaces with little or no fairing where obtaining ideal surface preparation and profile is not feasible. The intact coatings around the repair area must be tested for adhesion and compatibility with the Awlgrip Systems. See the Previously Painted Surfaces section for details of these tests.

On heavily faired surfaces this system should be limited to repairs 1 sq ft. (30cm2) or less of bare metal. Repairs exposing more than 1 sq ft. (30cm2) of bare metal are indicators of serious problems in the paint system. Full repair would require removal of large areas of the coating system and preparation as per full system application.

After completion of the repairs the blistered areas and surrounding sound surfaces would be prepared and primed as per the “Previously Painted Surfaces” section.

Note: Corrosion, and the resultant blistering, is often caused by construction features such as stitch welded attachment of rails and brackets, contact of dissimilar metals at hardware attachments and improperly grounded electrical systems.

Repairs which only address the blister and not the root cause of the blister, usually result in reoccurrence of the blister in the same area.

A detailed condition report should be written for those responsible for the yacht’s maintenance. With the report, the owner, or owner’s representative, can make an informed decision on how extensive the repair process should be.

  1. Thoroughly clean and degrease the surface. Use commercial detergents, steam cleaners, or pressure washers. Be sure all detergent residue is rinsed from the surface. Use Awlgrip Wipe-Down Solvent (NA/AP: Awlprep Plus T0115; EU: Surface Cleaner T0340) for a final wipe down of the surface.
  2. Grind with a 36–60 grit disk to remove blistered materials. Grind until all loose materials are removed and you reach a hard, tightly bound edge to the paint system. Then bevel/feather the edge of the repair at a 6:1 ratio. The slope of the repair must be at least 6 times the depth. If more than 1 sq ft. (30cm2) of bare metal is exposed, re­grind the areas with a 36 grit disk until a hard, tightly bound edge is obtained.
  3. a: On areas where fairing will be needed: Grind bare metal with a 36–60 grit disk until bright, silver metal is obtained. After grinding, remove corrosion from the pits by spot blasting.
    b: On smooth, unfilled areas, clean the metal bright using 120–180 grit paper. Spot sand blasting may be necessary to remove corrosion from pits.
  4. Blow off the surface thoroughly with clean, dry compressed air or vacuum to remove all blast/grind/sanding residue and any dust or dirt. Use a brush or broom if necessary.
  5. To hold your surface preparation and prevent the need to repeat this work, the substrate should now be primed as detailed below.

    Tip

    For the ultimate anti–corrosive scheme first prime the prepared aluminum with Max Cor CF. Note: This must be within 4 hours of final surface preparation. Spray apply Max Cor CF in one full wet coat to approximately 0.8–1.4 mils (20–34 microns) wet film thickness to achieve 0.6–1.0 mils (15–25 microns) dry film thickness.

    Important

    Allow to cure for a minimum of 17 hours.

    Important

    Following removal of the blistered material and the aluminum being suitably prepared, the first coat of primer must be applied within 8 hours, ideally within 4 hours. Products in Step 5 must be applied within 72 hours of the completion of Max Cor CF application.

    Caution

    Do not use a roller to apply Max Cor CF. See previous caution regarding wicks.

  6. Apply Hullgard Extra by roller or spray.

  7. Note: Only apply Hullgard Extra by roller if applying over Max Cor CF due to risk of snagging roller fibers. For spray application, apply 9 mils (220 microns) wet film thickness to achieve 4 mils (100 microns) dry film thickness. Allow a minimum drying time of 3 hours at 68°F (20ºC) before proceeding.


Roller application will require at least two coats to achieve 4 mils (100 microns) dry film thickness. Allow a drying time of 3 hours at 68°F (20ºC) between coats.

Depending upon the conditions it may be possible to proceed to filling and surfacing without the need for sanding (See Fairing and Surfacing section for detailed information). Please consult product datasheet for further details.

For thin film, no fairing systems (with Max Cor CF applied to the repaired areas) e.g. masts, window frames and other smooth, cast or extruded parts, see the Thin Film Unfaired Systems section.

Anodized Parts

This is designed for the coating of smooth parts which require no fairing or filling. Unlike non-anodized aluminum, anodized aluminum requires a pre-primer. This general system is for anodized mast, spars, equipment and accessories that are above deck and require no filling or fairing.

  1. Thoroughly clean and degrease the surface. Use commercial detergents, steam cleaners, or pressure washers. Be sure all detergent residue is rinsed from the surface. Use Awlgrip Wipe-Down Solvent (NA/AP: Awlprep Plus T0115; EU: Surface Cleaner T0340) for a final wipe down of the surface.
  2. Anodized parts should be sanded with 80–120 grit paper to “break” the anodized surface to ensure adhesion of the pre-­primer.
  3. For architectural grades of anodized aluminum, the surface must be thoroughly sanded with 40–80 grit paper until a surface profile is present. The surface must then be thoroughly cleaned and degreased with Awlgrip Wipe-Down Solvent (NA/AP: Awlprep Plus T0115; EU: Surface Cleaner T0340).
  4. Apply Wash Primer CF. Apply one full wet coat to approximately 2-4 mils (50-100 microns) wet film thickness to achieve 0.25-0.50 mils (7-13 microns) dry film thickness. Allow to cure 1 hour.

After sanding, the surface is now ready for priming.

Tip

If substrate only requires pre-priming and topcoating the following Fast Drying Topcoat System can be applied. Prepare the substrate as per steps 1–3 (see page 26). Sand with 180-220 grit sand paper. Apply by air atomized spray 1 coat of Wash Primer CF at 2 mils (50 microns) wet film thickness giving a dry film thickness of 0.25 mils (6 microns). (Several passes are required with the spray gun for a good surface. The first pass should be relatively slow (5–10 cm/2–4 inches per second). This pass is to obtain basic coverage). Following sanding, if necessary, surface is now ready for topcoat application.

Tip

Alternatively if the anodizing is removed through sanding, Max Cor CF can be used in place of Wash Primer CF. For details on the preparation and application of Max Cor CF, following removal of the anodized layer, please refer to the section on surface preparation and priming of non–anodized aluminum in this guide.