Effect of Surface Treatment on Adhesion to Metals

By Brian Knight

We have performed tens of thousands of adhesion tests over the years and many of these tests were done on metal surfaces. Below is a summary of tests done on a variety of metal surfaces and done with a variety of surface preparations. As you look at the chart, notice the surface preparation that gives the highest number.

All the tests shown below were performed using a PATTI (pneumatic adhesive tensile test instrument) meter. We chose this test method as our default adhesion test method about 14 years ago because it yields consistent results, is relatively easy to perform, and is economical. The results shown below show the tensile strength of a glue-joint. Not all joints are stressed in tension, so consider the data to be comparative, not a specification.

Most of the tests were done with WEST SYSTEM® 105/205 or 105/206. Most were allowed a two-week room temperature cure before the test was performed.

Metal Cleaning Preparation Tensile adhesion (PSI)
Copper
sand 80-grit wet sand  1503
sand 80-grit  1065
Aluminum
2024 T3
sand 80-grit wet sand  1330
sand 80-grit  1126
Steel sand 80-grit  1320
sand 80-grit wet sand  1352
Lead (pure) sand 80-grit wet sand  2753
Cast Iron sand blast  3214
sand 80-grit wet sand  3970
Stainless
Steel 316		 sand 80-grit  957
sand 80-grit  974

Epoxyworks 22 / Winter 2004