written by:
Tiffany Vines
Tammy Loehrke
Jon Valasek

Impact testing is used to:
  • evaluate the point at which the coating fails to protect the substrate by being degraded
  • evidence of the point of failure includes but not limited to the coating cracking , chipping, or completely separating form the substrate.

 

 

 

Prepared substrates on aluminum foil from the coatings preparation activity and the impact tester which consists of:
  1. A tube
  2. A set of three marbles
  3. A glass jar (50 mm in diameter by 50 mm high)

Eye protection should be observed throughout this activity.
  1. Obtain coatings on prepared substrates and impact tester.
  2. Place the aluminum strip with coating side up over jar opening so that the strip completely covers the jar opening.
  3. Place the nail provided with the tube into the 15 cm hole so that the nail goes through the tube and provides a barrier for the marble.
  4. Mass the marble you will use in the test and drop it into the tube so that it rests above the nail at the 15 cm mark.
  5. Center the tube over the jar containing the strip at least 1.0 cm above the jar. Measure the distance from the top of the strip/jar to the bottom of the tube and record that distance.
  6. While holding the sides of the strip firmly to the sides of the jar, pull the nail out of the tube.
  7. Carefully removed the marble from the strip and observe the results of the impact of the marble on the coating.
  8. Repeat steps 2 through 7 using an untested portion of the strip and increasing the distance the marble falls by 15 cm by moving the nail further up the tube.
  9. Continue to increase the distance the marble moves until the coating deforms to the point determined by your team and teacher.
  10. If after 105 cm the coating shows no sign of deformation, use a second marble and repeat the process starting at the 15 cm mark. If after 105 cm the two marbles show no deformation, use a third marble. Continue the process until the coating deforms.

 

 

Develop a suitable means to visually present your findings to include a comparison of impact resistance to type of coating tested.

Write a summary of your analysis and include which type of coatings would be suitable for high impact use such as coatings on toys and low impact use such as coatings on furniture.

 

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