Residual stress testing is done on customer molded parts to see how solvents affect the materials.

The parts are placed in a plastic container and immersed in an aggressive solvent. MEK and ethyl acetate are the most common solvents used.

The samples are immersed in the solvent for 1 minute, and then removed and inspected for damage. If no failure is seen, the concentration of the solvent is increased and the test is repeated until failure is observed.