Testex Tape

• Steel is often abrasive blast cleaned or roughened prior to painting.
• The peak-to-valley height of the resultant surface profile is an important factor in the performance of applied protective coatings.
• Low profile may reduce coating bond strength (adhesion).
• High profile may lead to insufficient coverage and possibly rust prematurely
• For these reasons, surface profile should be measured prior to coating application to ensure that it meets contract specifications.

Replica tape consists of a layer of compressible foam affixed to an incompressible polyester substrate.When pressed against a roughened (steel) surface, the foam collapses.

Acquire an impression of the surface.

Placing the compressed tape between the anvils of a micrometric thickness gage, and subtracting the contribution of the incompressible substrate (50 micrometers or 0.002 inches), gives a measure of the surface profile.