Gardner Heavy Impact Tester

The Heavy Impact Tester provides a wide range for impact resistance testing and is suitable for various coatings such as paints, varnishes, water-based wood coatings, high-viscosity plastic coatings, and laminated coatings. It can also be used for quality control of impact and penetration tests in construction materials such as plastics, resins, fiberglass, panels, and plywood.

The test methods comply with GB/T 20624.2-2006, ISO 6272-2, ASTM D5420, ASTM D2794, ASTM D3029, ASTM D4226, and relevant standards for water-based wood coatings in the chemical industry.

Two test methods are available:

Pass/Fail Test: A specified mass hammer is dropped from a defined height to determine whether the result meets the required specification.

Graded Test: The minimum height and/or mass causing coating cracking or substrate detachment is determined by gradually increasing the drop height and/or weight.

Structure and Specifications

Structure

The tester mainly consists of a guide tube, height limiting ring, and base. The guide tube is marked in both centimeters and inches, corresponding to ISO and ASTM standards.

Specifications

a. Base dimensions: 300 mm × 240 mm × 35 mm (L × W × H)

b. Guide tube height: 1250 mm

Testing Procedure

(1) Test Preparation

Prepare a magnifier with 10× magnification.

Place the instrument on a horizontal surface.

Select and install the appropriate indenter according to the test standard.

Select and install the corresponding die.

Insert the guide tube and lock it with the handle.

Install the height limiting ring from the top of the guide tube and fix it with screws.

(2) Test Steps

a. Pass/Fail Test

Adjust the height limiting ring to the required drop height.

Place the test panel on the die, with the coated surface facing up or down, allowing concave or convex deformation. Clamp the panel and release the hammer to impact the sample.

Inspect the coating using a magnifier to determine cracking or detachment from the substrate, and check if the substrate is cracked.

Repeat the test at four additional locations (total of 5 points). If at least 4 points show no cracking or detachment, the coating is considered qualified.

For water-based wood coatings (chemical industry standard):

Indenter diameter: 12.7 mm

Hammer mass: 300 g

If no cracking or coating detachment occurs within the deformation area (optionally marked with a colored pen for inspection), the point is considered “pass”.

Test two panels, each with 5 impact points. If at least 3 points on one panel pass, the result is “pass”.

b. Graded Test

(1) Adjust the drop height where no damage is expected initially.

(2) Perform the impact test as described above.

(3) Inspect the coating. If no cracks appear, increase the height stepwise (increments of 25 mm or multiples). Use a 1 kg hammer initially; if no failure occurs at maximum height, repeat with a 2 kg hammer.

(4) Once cracking occurs at a certain height, perform 5 impacts each at this height, 25 mm above, and 25 mm below (total 15 impacts).

(5) Inspect and record results. The impact failure endpoint is determined based on the height/mass combination where most failures occur.

(6) If no clear endpoint is obtained, repeat steps (4) and (5), using the range of heights as the result.

c. Hammer, Indenters, and Dies

Indenter a: 12.7 mm (0.625 in)

Indenter b: 15.9 mm (0.5 in)

Die a: 16.3 mm (0.64 in)

Die b: 31.75 mm (1.25 in)

Drop hammer: 300 g (for water-based coatings standard)

Drop hammer: 1000 g + additional 1000 g

Standard Combinations:

ASTM D2794 (Coatings impact resistance):

Indenter a – Die a

Indenter b – Die a

ASTM D3029 (Rigid plastics, Method G):

Indenter b – Die a

Indenter b – Die b

ASTM D4226 (PVC impact resistance):

Indenter a – Die a

Chemical industry standard (water-based wood coatings):

Indenter a – Die a

Precautions

(1) Tests should be conducted under constant temperature and humidity conditions.

(2) Sample preparation, panel treatment, and drying must comply with relevant standards.

(3) After testing, remove all accessories and store them properly to keep the instrument clean.

Packing List

Main unit: 1 set

1 kg hammer: 1 pc

1 kg additional weight: 1 pc

300 g hammer: 1 pc

Φ12.7 mm indenter: 1 pc

Φ15.9 mm indenter: 1 pc

Φ16.3 mm die: 1 pc

Φ31.75 mm die: 1 pc

Height limiting ring and screws: 1 set

FAQ

1.What is a Gardner Heavy Impact Tester?

The Gardner Heavy Impact Tester is a specialized instrument used primarily in the quality control of paint and coatings. It evaluates the resistance of coatings to mechanical damage, particularly impacts. By dropping a standardized weight from a specified height onto a coated surface, the tester can reveal how well the coating withstands sudden force, which is crucial for ensuring product durability and performance.

2.How does the Gardner Heavy Impact Tester work?

The Gardner Heavy Impact Tester operates by allowing a heavy weight to drop freely from a set height onto the surface of a coated material. The size and weight of the impacting body can be adjusted according to the testing standards. After the impact, the coated surface is inspected for defects such as cracks, peeling, or other forms of damage, which helps assess the durability of the coating.

3.What are the applications of the Gardner Heavy Impact Tester?

The Gardner Heavy Impact Tester is widely used in various industries, including automotive, aerospace, and consumer goods. It is beneficial for testing coatings on surfaces that are likely to encounter physical damage during use. This includes everything from car finishes to protective coatings on industrial equipment, helping manufacturers ensure their products can withstand everyday wear and tear.

4.What standards does the Gardner Heavy Impact Tester comply with?

The Gardner Heavy Impact Tester is designed to meet specific industry standards for impact testing, such as ASTM D2794 and ISO 6272. Compliance with these standards ensures that the results obtained from the testing are reliable and can be compared across different products and manufacturers. This adherence is crucial for certification and quality assurance in production processes.

5.How do I choose the right impact weight and drop height?

Choosing the right impact weight and drop height for the Gardner Heavy Impact Tester depends on the specific requirements of the test and the type of coating being analyzed. Typically, the manufacturer will provide guidance on standard configurations, but the selection can also be influenced by the expected usage conditions of the coated product. It’s important to consult relevant testing standards or seek expert advice when determining the appropriate settings.