Important Information about Conversion Coatings

Have you ever asked yourself why industrial painting contractors Indiana use conversion coatings? A clean surface may not be all that is needed in industrial painting. The type of substrate to be painted determines whether or not additional surface chemical treatment is needed.

In case you are painting wood, you will only need a clean surface and surface smoothness. A wood surface has polar cellulosic composition that provides excellent adhesion base for paints and this makes it unique from other types of surfaces. Plastic surfaces require chemical treatment unlike wood surfaces. Some industrial painting contractors Indiana paint plastic surfaces directly after cleaning them and achieving a good paint adhesion. Other plastics with low polarity such as polypropylene and polyethylene need additional treatment so as to enhance the adhesion of the surface. Just like the plastics, some metals are painted immediately after cleaning the surface. Such metals do not have severe requirements for corrosion or adhesion resistance. Surfaces that are low priced and are expected not to last for long can fall in this category.

Conversion coatings for metal

In most cases, industrial painting contractors Indiana paint most metals with the conversion coating after cleaning. Conversion coatings are chemically developed surface coatings to help shield the metal from moisture, air and industrial gases. This makes the metals resistant to corrosion and provides a roughened surface that has high adhesion. Conversion coating surfaces have micro porosity and micro roughness in form of pores, undercuts and fissures that form excellent stratum into which the paint flows to create a good hold onto the surface. This conversion process also leaves slightly acidic residual pH on the surface and this is more receptive to good paint adhesion that has an alkaline pH Solutions that are alkaline in nature can degrade the paint resins and find use in the paint strippers. Alkaline pH on surfaces that needs to be painted is undesirable.

Enhancing long term paint

You can enhance long term paint adhesion thermal expansion and the contraction buffer that is provided by conversion coating between the paint and the metal. The contraction and expansion coefficient of the paint film is many times that of the metal underneath. Conversion coating is intermediate in the expansion and contraction features. The severity of the difference in rate of expansion between the underlying metal and the paint is lessened when sudden cold and hot changes are experienced.

The conversion coating this reduces the lateral creep of corrosion from gouges and the scratches that have gone through the paint down to the bare metal. The conversion coating helps in inhibiting the undercutting of paint by loss of the underlying metal and spread of rust away from a scratch line is then slowed significantly. The thickness of the conversion coatings are given in weight per area unit. The reading is traditionally on mg/sq ft in Indiana. The thickness for conversion coatings to be painted by industrial painting contractors Indiana varies. They are usually specified within certain ranges for optimum corrosion and adhesion resistance for a given product.