The Importance of Adhesion Testing for ACM Panels as Painting Supports

Adhesion testing is crucial for the longevity and stability of artwork on Aluminum Composite Material (ACM) panels. This process evaluates whether the paint will bond effectively to the ACM surface, ensuring durability against environmental and physical stressors. It directly affects whether the paint will remain securely bonded to the surface over time, ensuring the artwork's integrity against environmental stresses such as humidity, temperature changes, and physical handling. A strong adhesive bond minimizes risks of peeling, cracking, or delamination, which could otherwise compromise the visual and structural quality of the piece. Artists must understand the relationship between primers, substrates, and painting mediums to create durable works. This article explores why primers are essential, addresses misleading claims by commercial ACM panel manufacturers, and outlines reliable testing methods to ensure strong adhesion.

Why Adhesion Primers Are Essential for ACM Panels

Primers play a vital role in the adhesion process. They chemically and mechanically bond to both the ACM panel and the paint medium by forming a molecular connection. This occurs through interactions between the primer’s adhesive and the panel’s surface and cross-linking within the primer itself. This bond creates a durable connection, ensuring the paint remains securely attached even under environmental stresses. This dual adhesion ensures stability by preventing peeling or delamination over time, even under varying environmental conditions. The paint may flake or delaminate without this bond over time, compromising the artwork’s integrity.

ACM panels are smooth, non-porous surfaces composed of aluminum veneers over a solid polyethylene core. This composition makes adhesion inherently challenging. Primers address these challenges in three ways:

  • Promoting Adhesion: Primers bond chemically and mechanically to the ACM surface, preparing it for paint.
  • Protecting the Surface: They prevent oxidation and corrosion, which could degrade the paint.
  • Improving Uniformity: Primers provide a suitable surface receptive for the painting medium used by the artist, ensuring smooth paint application and consistent results.

According to the ASTM D3359 standard for adhesion test methods, proper preparation and priming significantly improve adhesion, particularly for slick surfaces like aluminum.

Debunking Commercial ACM Panel Claims: Adhesion and Archival Standards

Many ACM panels marketed to artists make claims like “archival,” “acid-free,” or “ready to paint.” These phrases can be misleading. For example, panels marketed as “archival” may lack proper adhesion testing, leading to issues like delamination over time. Similarly, claims such as “acrylic-ready” or “ready to paint” often overlook the necessity of primers to ensure proper adhesion. Artists may assume these panels require no preparation, only to find that their work is compromised by peeling or cracking later. For instance, products like AlumaComp panels from Jerry’s Artarama claim to be archival and ready for paint but often lack evidence of adhesion testing.

  • Archival Misuse: “Archival” implies long-term durability. However, even archival-grade materials may not ensure paint adhesion without appropriate priming.
  • Irrelevant Terms: Claims such as “acid-free” apply to paper-based materials, such as watercolor or drawing papers, not aluminum. Aluminum doesn’t interact with pH in the same way.
  • Unsubstantiated Readiness: Phrases like “ready to paint” often lack evidence of adhesion testing. If left unprimed, panels may fail to support paint in the long term.

Artists should critically assess these claims. Companies like Artefex and Natural Pigments provide reliable data on adhesion, offering products tested according to ASTM standards.

Adhesion Testing Standard: ASTM D3359

The ASTM D3359 standard describes two methods to evaluate coating adhesion. The choice between Method A and Method B depends primarily on the coating thickness:

Method A: Suitable for coatings thicker than 125 μm (5 mils). This method involves making an X-cut through the coating to the substrate, applying tape, and removing it to measure coating removal.

Method B: Ideal for coatings thinner than 125 μm (5 mils). This method uses a grid pattern of cuts, followed by tape application and removal, offering more precision and suitability for laboratory conditions.

Test Method B - Adhesion Test Results

These tests rate adhesion on a scale from 0 (complete failure) to 5 (perfect adhesion). Within 90 seconds of applying the tape, it is removed rapidly at an angle as close to 180° as possible to evaluate the bond. The grid area is inspected for breaks in the coating using an illuminated magnifier. The results are rated as follows:

  • 5B: The edges of the cuts are completely smooth; none of the squares of the lattice is detached.
  • 4B: Small flakes of the coating are detached at intersections; less than 5% of the area is affected.
  • 3B: Small flakes of the coating are detached along edges and intersections; 5-15% of the lattice is affected.
  • 2B: The coating has flaked along the edges and parts of the squares, affecting 15-35% of the lattice.
  • 1B: Flaking occurs along the edges in large ribbons, and whole squares detach; 35-65% of the lattice is affected.
  • 0B: Flaking and detachment exceed Classification 1B.

Both methods emphasize the importance of substrate preparation and primer selection.

Companies Demonstrating Adhesion Testing

Among manufacturers, Artefex and Natural Pigments stand out for their focus on adhesion testing. Artefex Panels: Artefex tests their pre-primed ACM panels with ASTM D3359 standards. Their lead and titanium alkyd grounds consistently demonstrate excellent adhesion.

Rublev Colours Primers and Their Performance

The Rublev Colours brand offers primers designed explicitly for ACM panels. Their products undergo thorough testing to ensure compatibility and durability. Key products include:

  • Lead White Alkyd Ground: Demonstrated excellent adhesion, with 0% removal in multiple tests, providing artists with a reliable and durable option.
  • Titanium White Alkyd Ground: Like the Lead Alkyd Ground, this primer also achieved 0% removal in tests, highlighting its strong adhesive properties.
  • Lead White Oil Ground: Showed weaker performance, with 15-65% removal depending on the application, making it less suitable for demanding adhesion requirements.
  • Tempera Ground (VAE Primer): Performed well with 5-15% removal, offering versatility as an alternative to traditional acrylic grounds.

These companies provide artists with confidence backed by evidence-based testing.

ASTM D3359 Adhesion Test Method B of Primers on ACM Panel
Adhesion test of lead alkyd ground
Above: Adhesion test of Rublev Colours Lead Alkyd Ground showing smooth edges and no detachment of the primer, indicating a classification 5B
Adhesion test of Tempera Ground
Above: Adhesion test of Rublev Colours Tempera Ground (VAE Primer) showing smooth edges and no detachment of the primer, indicating a classification 5B


DIY Adhesion Testing for ACM Panels: A Guide for Artists

Artists can perform their own adhesion tests using simple tools and methods adapted from ASTM. While these DIY tests are simpler than professional standards, they provide valuable insights into material compatibility and help ensure high-quality adhesion for long-lasting artwork. By performing these tests, artists gain control over their materials, ensuring the quality and longevity of their work. This empowers them to select and prepare their panels confidently, safeguarding their creations against long-term issues like delamination or cracking.

How to Perform Adhesion Tests

  1. Prepare the Surface: Clean the panel to remove grease or contaminants.
  2. Apply the Primer: Follow the manufacturer’s instructions and allow it to cure fully.
  3. Cut a Test Grid: Use a sharp blade to create a cross-hatched pattern on the surface. Ensure cuts reach the substrate without damaging the coating on the aluminum veneer underneath the paint or primer.
  4. Apply Tape: Use pressure-sensitive tape and press it firmly onto the grid.
  5. Remove the Tape: After 60 to 90 seconds, pull the tape off quickly at a 180-degree angle.
  6. Assess the Results: Examine the grid for paint or primer removal. A score of 5 indicates no removal, while lower scores signal adhesion issues.

Adhesion is the foundation of durable and lasting artwork on ACM panels. Primers bridge the gap between the aluminum surface and the artist’s chosen medium, ensuring strong, stable bonds. While some commercial ACM panels lack evidence of proper adhesion testing, companies like Artefex and Natural Pigments provide reliable, tested solutions. Artists can further ensure the quality of their materials by performing their own adhesion tests. These actionable steps help artists to select the right panels, apply suitable primers, and protect their artwork from future issues like delamination or cracking. By prioritizing adhesion, artists can create works that endure for generations.


Bibliography

ASTM International. Standard Test Methods for Rating Adhesion by Tape Test (ASTM D3359). Mar 7, 2023. Last accessed on January 20, 2025.  Access Online.

Natural Pigments. “Painting ACM Panels for Painting.” Natural Pigments Artist Materials. April 16, 2014. Last accessed on January 20, 2025. Access Online.

Artefex. “How Well Do Grounds Adhere to ACM Panels?” Artefex Product Testing. October 7, 2020. Last accessed on January 20, 2025. Access Online.

Golden Artist Colors. “Will It Stick? Simple Adhesion Testing in Your Studio.” Just Paint. January 21, 2019. Last accessed on January 20, 2025. Access Online. Access Online.


The featured image of this arficle is of a cross-cut adhesion tester by Jarp. For more information, visit Jarp.


Primers for ACM Panels

  1. Rublev Colours Lead Alkyd Ground
    Lead Alkyd Ground
    As low as $48.70
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  2. Rublev Colours Titanium White Alkyd Ground
    Titanium White Alkyd Ground
    As low as $19.50
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  3. Tempera Ground
    Tempera Ground
    As low as $18.70
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