Brush application

Application of paint.

Table of Content.

Section	Title	Page
7.1 7.1.1. 7.1.2. 7.1.3. 7.1.4.	Application methods – Introduction Brush application Roller application Application by spraying Application technique – airless spray	7.2 7.3 7.4 7.4 7.5
7.2 7.2.1. 7.2.2. 7.2.3. 7.2.4. 7.2.5.	How does spray equipment function Low pressure spray equipment High pressure spray equipment Plural component spraying (Two component spraying) Float coating Paint-drum pump	7.7 7.7 7.8 7.9 7.9 7.9
7.3. 7.3.1. 7.3.2.	Treatment of equipment before and after application Before application After application	7.10 7.10 7.11
7.4	Application and curing condition	7.11
7.5.	Safety aspects during application	7.14

Application of paint.

7.1. Application methods – Introduction.

The protective properties of paint have no effect unless the paint is applied correctly. Many people think that all the problems are solved as soon as the anti-corrosive paint is applied in the specified film thickness. It is, however, a fact that the method of application can be equally important with regard to the final result. The following general guidelines for application are recommended:

· All coating systems must be applied in accordance with their product data sheets.

· Application must take place under controlled climatic conditions suitable for the particular product in use.

· If thinning of the paint is required, this must be done in accordance with recommendations given in the data sheets.

· Correct coating intervals, i.e. max./min recoating times according to data sheets, must be respected.

· Film thickness measurements must be made after each stage of application. The wet-film thickness of each coat must be checked and adjusted, so that the coating thickness meets the requirements in the specification.

· Maximum and minimum paint film thicknesses given by the technical data sheets from the paint supplier must be satisfied.

· Stripe coating must be done with brush for the first coat. (Roller application can be used on subsequent coats).

The paint must be applied by means of the most suitable equipment and correct application technique. Methods of application include the following:

· Brush

· Roller

· Low-pressure spray (conventional spray)

· High-pressure spray (airless spray)

· Other methods

Figure 7.1.

All methods have their good and bad points.

Brush application

From a technical point of view the ideal method of applying a paint is with a brush. The advantage of brushing is that the paint is worked well into the surface so that gaps, pores and pits are filled up, for example in uneven welding seams. Also the paint brush is moved back and forth, moving the paint or coating in two or more directions. Each of these actions makes the coating flow over the surface in several directions, increasing the intimate contact of the paint with the surface. This is particularly valuable where a coating with only low wetting characteristics is applied. It is also an advantage where the surface is rough, hand prepared, or where there may be surface contaminants or dust present. Contaminants on the surface must of course be avoided! Still, any dust, water drops or other impurities present will, to a certain degree, be moved by the brush thus allow for the paint film to have good contact with the surface. Without this physical action the surface may not be wetted and there will be poor adhesion between the coating and the substrate when the coating has dried.

Another action of the brush is that of stippling or dabbing the coating on to the surface. This is particularly important when applied around bolt heads, rivets, welds, and in corners. Such a movement aids in filling pinholes, pits and rough surfaces with the coating. In many cases the physical action created by using the brush is the only one that can make the coating flow into these areas. Neither rolling nor spraying will do this so well.

Figure 7.2.

Дата добавления: 2015-10-26