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Brushes
A brush is a collection of bristles attached to a handle by means of a plastic setting compound and protected at the base by a metal ferrule. Bristles should be checked carefully for quality. Cheap bristles are to be avoided. High quality “Natural” ( Pure Chinese Hogs Bristle) or “Synthetic ( Polyester or Nylon) are available. The virtue of the Chinese Hogs Bristle is a natural splitting at the end called “Flagging”, which enables the brush to hold more paint than other natural animal bristles as well as having a multitude a small hairs at the tip of the bristle that gives a finer finish when brushing out the paint.
 
  Natural or Pure Bristle (Chinese Hogs Bristle)
Natural bristle was probably one of the first type of animal bristles that was found to work well as a bristle in a paint brush. The natural flagging of the bristle end produces fine, wet brush marks which would have a better chance of leveling and disappearing as the paint dried. This type of bristle works well in oil paints and industrial enamels. It does not work well when used to apply water based coatings and paints. The water in the coating causes the bristle to soften and swell with water. The brush will lose flexibility and become soft and lose shape.
 

 

Synthetic Bristles ( Polyester / Nylon)
Synthetic bristles are an attempt to copy the good qualities of the Chinese Hogs Bristle using plastic components like Polyester and Nylon. These filaments do not react to water so they are best suited when using a coating that contains water ( Latex, Acrylics and Vinyl Water-Borne Paints) Polyester reacts very little or not at all to most solvents so Polyester brushes are sometimes called “ All Purpose”. Polyester brushes do a good job of copying Chinese Hogs Bristle. Used in latex or low sheen alkyds, Polyester brushes work very well. When used in High Gloss Alkyds and Varnishes the Polyester brushes will produce brush marks that are too visible. Even though Polyester brushes can be used in many types of coatings they are best suited for water based Architectural coatings. Pure Chinese Hogs Bristle work very well in Industrial enamels like Epoxies and Polyurethanes.
 
  Chinese Hogs Bristle
Synthetic Bristle
 
   

 

Types of Brushes:

Brush types may be classified into five main types: 1. Wall Brushes, 2. Sash and Trim Brushes, 3. Enameling and Varnish brushes, 4. Stucco and Masonry Brushes, 5. Specialty Brushes.

 

 

1. Wall Brushes: These Brushes are flat and range in sizes from 3 to 6 inches wide. They have a short heavy handle and the bristle end is square. They were used primarily for wide, large surfaces but today they are used mostly for brushes siding and wide frames. The roller has replaced the wall brush for painting walls. (see fig. 1- Wall Brush).  
  2. Sash and Trim Brushes: These are available in four common types : round, oval, flat with a square edge, and flat with an angled edge. They range in size from 1-1/2 inches to 3 inches in width. The angled sash tool is by far the most popular because it is not only for trim and sash painting but can be used to “Cut In” a surface before roller painting a surface. Because rollers cannot get into a corner without ruining the adjoining face the edge must first be painted with a brush. The roller is then used to fill in the main surface and overlapping the brushed surface as much as possible without hitting the adjoining surface.
Angular Sash Tool

Flat Sash Tool
 
  3. Enameling and Varnish Brushes:
These brushes have shorter but finer bristles than other brushes so they can lay down high gloss and clear varnishes smoothly and evenly. They are usually made from high quality Chinese Hogs Bristle or Ox Hair. The average size is between 2 and 3 inches and have a flat or angular tip.

Enameling and Varnish Brushes
 
  4. Stucco and Masonry Brushes:
Stucco and Masonry Brushes are wide and look like flat wall brushes. Nylon is preferred as a bristle because the surfaces are rough as well as the coatings are usually high in alkalinity. Animal hair bristles would wear out quickly or break down because of the chemicals in the coatings used.

Stucco and Masonry Brushes
 
  5. Specialty Brushes: There is a wide range of specially designed brushes that are used for specific jobs. Some of the more common ones are Radiator Brush; has an off-set handle to allow the painter to reach around corners and behind objects. Commonly used in Commercial and Industrial Painting. Stencil Brush; Used to transfer a coating on a stencil pattern. A short , round brush that is usually used in decorative stencil painting. Badger Haired Blender; A brush made from actual Badger hair. A very expensive brush used when softening and blending applied glazes. ( Graining and Marbling) Artist Brushes; Assorted sizes and types used for decorative painting and small touch-up work. ( See fig. 5 Specialty Brushes)  
 

Artist Brushes or Fitch

Badger Blender
 

Radiator Brush

Stencil Brush
   

 

Methods and Procedures
There is unlimited types of situations where brush painting can be performed. The over-all result should be a reasonably smooth surface with very little brush marks and a very even gloss. To get to this point relies on the skills of the painter as well as the characteristics of the coating, the environment and the surface. Here are a few points to remember when applying paints with brushes.

1. Always used thinned, strained coating. Most manufacturers of coatings will allow their materials to be thinned up to ten percent without any problems. The thinner that is added may have slower evaporation rates than the solvent in the paint. This would allow for better flow and leveling of the paint just after application. ( There are special additives that are manufactured for the purpose of slowing down the “Tack Time” of the paint - Materials like “Penetrol” for Alkyds and “Floetrol” for latexes make the paint more brushable and able to produce a smooth finish. )

2. Use the right size and type of brush: As stated in the previous information, Pure Bristle works well in Oil, Alkyd and Industrial Coatings, while Polyester works well in Latexes and Water-Borne paints. Use the largest brush possible to do the job. Small brushes may appear to be easier to handle but produce more brush and stroke marks than large brushes. Large brushes can do the job quickly, with less re-dipping than smaller brushes. The term “ Keep a wet edge” is very Important. A large brush will allow for quicker application thus allowing the painter to always have a wet edge to work back to.

3. Plan the work: Always know where to start and where to end. Typically painters work backwards. The work is usually started in the most difficult and hard to reach areas then work progresses out into the outside or more visible areas. Top to bottom is fairly normal as well as doing corners first then applying paints to the larger surfaces and faces.

4. Handling the Paint and Brush: The painter cannot work successfully out of a full container. The paint pail should be ¼ to 1/3 full. The painter dips only the first 2 to 3 inches of the bristle into the paint then taps the wet bristles once or twice against the exposed surface of the inside of the paint pail. This will remove only a small amount of excess paint and still leave the brush fully loaded with paint. This operation is very important. If the painter wipes the loaded brush against the lip of the pail, too much paint will be removed. This will force the painter to try and drive out the paint that is inside the brush by pushing too hard against the surface to be painted. This is a common mistake made by amateurs. The paint on the outside of the brush is what is needed. Wiping the brush against the lip of the pail should only be done when too much paint has accumulated at the base of the brush or the brush is to be cleaned.

5. Brushing Techniques: There are many styles of brushing but there is one that is the most used. The first step is to cut in the edge if there is one then apply a full wet coat to a small area ( 1 to 2 square feet) Immediately cross brush this area ( do not apply more paint but quickly apply brush strokes perpendicular the first set of strokes. ) Again, immediately follow cross brushing with feathering out strokes in the same direction as when applying the paint. (Feathering strokes should start in a dry, unpainted area or at a corner. The brush in drawn through the wet paint in one full stroke and lifted from the paint while the brush is still moving. If the painter puts the brush down into the wet paint then started moving a definite line would be produced called a “Start Mark”. These start marks are unacceptable and are blemishes on the surface. The next area is then painted and the process repeats itself. The new area is blended into the first area. It is extremely important that this operation be quick so the areas can blend well . Over brushing of the paint should be avoided as the coating will not have a chance to flow out properly.

6. Typical Problems: The biggest problem painters have is when trying to brush fast drying finishes. Coatings and Paints like Latexes, Water-Borne, and fast dry Primers and Enamels will tack up too fast or are naturally quite thick and do not flow out. Slower evaporating solvents can be added and the environment could be cooled down to allow the paint to flow properly. Dirt and debris on or in the paint will be unattractive and could produce a rough finish. The coatings should be strained and the surface clean before painting. Dust in the air can also settle on the surface of the wet paint. The environment should be controlled during application and while the paint is drying to ensure a pleasing finish. Hairs and fibers from the brush can become loose and be deposited into the fresh paint. A good quality brush that has been cleaned properly will be less of a problem. If a brush has not been cleaned properly the residue of the old paint may contaminate the coating being applied. Brushes should be flushed with a compatible solvent then combed and spun out at least 3 times during the cleaning process. Runs and sags are created more by having an uneven paint surface than just a heavy application. Corners and edges can receive twice to three times the amount of paint needed and will run into the areas with a thinner film of paint. A consistent film thickness is important to prevent runs and sags. Too heavy a film build will cause slow drying of the paint as well as the possibility that the coating may crack when dry. Two thin, well applied coats, are better than one heavy one.


 
 
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