Paint We've All Heard The Word

Paint...it's a word most of us have heard of and understand, right? Well, when you really consider the word do you understand what it does or why it's actually capable of doing it? This article seeks to give you an grounding in what paint is and why it actually works, how does it transmit from tin to roller to wall and work so well and why.

Paint The Definition

Below is technically how paint is defined from an industrial paint point of view.

“Paint is a product, liquid or in powder form, containing pigment(s), which, when applied to a substrate, forms an opaque film having protective, decorative or specific technical properties”.

“Varnish is a product which, when applied to a substrate, forms a solid, transparent film having protective decorative or specific technical properties. In fact, varnish (clear coating) is substantially the same as a paint, the difference being that varnishes contain no pigments”.

All well and good you say but how does a coating such as paint actually work?

Coatings - How They Work

Coatings (what we'll describe here as industrial paint) prevent corrosion primarily by restricting the availability of water, oxygen and ionic materials to the metallic surface underneath. Coatings therefore are usually barrier materials. The basic idea of a barrier carries with it the idea of cohesiveness, resiliency and strength. It is toward these objectives of cohesiveness, resiliency and strength that the formulator of maintenance finishes continues the development of improved coatings.

In addition to the barrier effect, a coating may also possess other features calculated to prevent corrosion. Corrosion inhibiting pigments may be present. These act toward inhibiting the formation of electrolytic cells.

Pigments actually contributing strength to the barrier may also be made to regulate the acidity of the substrate surface and thus retard the corrosion for which acid conditions are required.

The surface of the topcoat may be resistant to bacterial growth and act to prevent corrosion from the penetrating acid products of microbiological metabolism. These considerations indicate the barrier and strength functions of maintenance coatings.

Paint Is a System Not a Standalone

If you've ever repainted the walls of your home if they are in good condition you may have simply recoated in emulsion and found that the colour and finish were of a good standard and pleasing to the eye, with no further coatings necessary. This is probably because your internal walls are already in good condition and the previous coating acts as a sort of primer paint.

In reality and especially in industrial paints for professionals, a paint coating is part of system and in general is not standalone.

Just as all architectural structures are built on a foundation, likewise all coating materials are built on a foundation. Just as large buildings require strong, carefully designed and constructed foundations, highly durable coating systems require carefully designed and constructed foundations. Just as a building consists of a number of interlocking parts, each part having a different function, likewise a coating system consists of a number of interlocking parts, each part having a different function.

In a building the parts are classified as foundation, superstructure and roof; likewise a paint system is classified as primer paint, intermediate coating and topcoat.

Paint Systems and Houses

You could even say that a paint system is very much like the house it will be coating! The list below shows how just like a house is built on levels of foundations so is a paint system if done correctly.

• ① The Basement ⇢ Primer Paint

• ② One Level ⇢ Midcoat

• ③ More Levels if required ⇢ Midcoat

• ④ The Roof ⇢ Top Coat

• ⑤ They all have a special function in the house ⇢ in the "Paint System"

The Difference Between Residential Painting and Industrial Painting

In construction small buildings where strength and long life is not required, minimum foundations and minimum superstructures are frequently tolerated.

Likewise, where a paint coating is not intended for industrial maintenance but is used for a short time and for decorative purposes only, considerations of strength, substrata, and therefore useful life are overlooked.

But in industrial new start projects and maintenance coatings where extremes of reliability, durability and resistance to corrosive action are required and must be achieved, the engineering factors of substrate preparation, strong foundation priming coats, reinforcing intermediate coats and weather resistant topcoats must be carefully provided for - you need an industrial paint.

A reliable new start or maintenance coating system consists of a primer, one or more intermediate coats and a topcoat. What it attaches to and how this attachment occurs is of basic importance in relation to the ultimate utility of the system.