What is a stripe coat when painting?

A coating system may consist of a coat of an anticorrosive material (primer) and one or more stripe coats. Stripe coats are applications of the top-coat (paint) which has been applied to edges of structure, welds, drain holes and other areas to over-come potential problems that can result when paint coverage is difficult/insufficient or non-uniform.

In a perfect coating system, the coating develops a constant thickness that never exceeds the proper limits (either too thin or too thick).

In reality, most coating materials exhibit behaviors that cause a reduced thickness around sharp corners like edges of structural steel profiles. This is caused by two phenomena: one is the surface tension of the coating material trying to "pull" from the edge, thinning the coat. Two is the chemical shrinking that many polymers exhibit when curing. Epoxies and polyurethanes show a marked shrinking. In adition to reduced coating thickness, the coating develops Residual Stresses that promote minute local failures in the coating, that progress until the coat fails or delaminates.

To reduce this phenomena, two things can be done: A) provide radiusing to reduce the Stress level and prevent coating failure at sharp edges. B) Apply a "Stripe-Coat" to all edges, welds, joints and high stress areas.

Radiusing is expensive and time consuming. Stripe coating is therefore the preferred solution. To provide a good Stripe-Coat, the painter must use a different color of material, painting a one to two inch stripe at every edge, weld, etc. For this action, there are special brushes, rollers and cartridges that supply the coating in the best way possible. Check Sherwin-Williams (and many others) specific materials for stripe-coat application. Check Theoretical principles at Academia.edu under "Fenómeno de generación de Esfuerzos Residuales".

Amclaussen, Mexico City.