Surface treatment of wooden furniture before painting

A piece of furniture usually needs to go through dozens of processes and meticulous work before it can be shaped.
Moreover, the quality control of each process operation directly affects the final quality and value of the furniture (painting).

In the furniture surface decoration, in addition to the professional technical requirements for coatings, coating technology, equipment/environment, the coated substrates (materials) must also meet the corresponding coating conditions .
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Therefore, the pre-processing of materials is the basis of painting.

Depending on the conditions of the wood substrate, the pre-treatment methods generally include

■ Dry

■Removing wood hair

■Remove stains (objects)

■Remove grease (resin)

■Bleaching

■Dyeing (artificial veneer)

■Padded/inlay

■Coloring/Painting

Operation content of material pre-processing

01 Drying of the substrate

• In order to prevent the deformation, cracking, shrinkage and expansion of the furniture in the later use, the quality, function and value of the finished product will decrease.

  
  Before painting, the moisture content of the substrate must be measured first, and the painting can only be carried out after the moisture content reaches the requirements.
  
  
  

• Generally, the humidity of furniture should be controlled at 9~14%.

  
  (When there are special requirements, it needs to be dried in accordance with the special requirements)
  
  

• The wood drying process is generally divided into 3 stages
  

*Wood drying: according to different material types and process requirements, there are different drying methods.

02 Removal of wood wool

Once the wood wool touches or absorbs water or solvents, it will be wet and swelled and stand up, so that the color cannot be evenly colored with the inside of the wood grain, but it accumulates around it, and there is a defect that the inside of the wood grain (conduit) is not colored.

After polishing, There appeared small white dots (sesame dots).
Therefore, it is necessary to fully sand and remove the wood wool before painting (for thin materials, avoid sand penetration) to provide a high-quality base condition for painting and coloring.

Polishing the job site

Ways and methods to remove wood hair↓

03 Decontamination/cleaning

The stains, grease, and glue marks on the surface of the substrate will directly affect the dryness, adhesion, and uniformity of the paint film.

Therefore, the coated substrate must be cleaned before painting.

04 Remove (seal) grease (resin)

For materials with a lot of grease, a sealing primer can be used for sealing; it can also be washed with alkaline lotion, then washed with water and dried.

(Alkaline solution: 5~6% sodium carbonate or 4~5% caustic soda solution)

For the material of the local resin (oil sac), first use a knife to remove the oil sac, and then fill it with the same material (the wood grain direction should be the same); if it is not allowed to remove it, it can be cleaned with organic solvents, turpentine, lacquer oil After cleaning, toluene, acetone, etc.

, after removing the grease, to prevent secondary exudation, it needs to be sealed first, and then work according to the procedure.

05 Bleaching (decolorization)

When furniture is painted in light colors, if the original color of the base material is inconsistent, the dark material needs to be bleached to achieve uniform painting conditions.

The bleaching agent can be a mixture of hydrogen peroxide (30%) concentration and ammonia (25%).

*Different bleaching agents have different bleaching effects on wood, and the actual effect needs to be confirmed and adjusted in advance.

06 Dyeing (man-made materials/technical veneer)

Due to the limited resources and high price of natural solid wood, man-made materials have been widely used in the field of furniture.

Rich effects of technical veneer 

Artificial veneer needs to be covered with a layer of film to protect it from light after dyeing.

Before painting, it is necessary to uncover or sand off the light-shielding protective layer covering the technical veneer before applying the paint.

07 Defect Filling

Furniture base materials such as hardwood and other materials with relatively wide and deep pipe holes, or materials with defects such as holes, nail holes, cracks, processing grooves, etc.

, in order to meet the painting requirements or closed process construction requirements, Generally, it is necessary to use putty, soil filling and other materials with filling ability to repair and fill up.

Fill in small holes (PE is recommended to fill in large gaps)

08 Coloring/Painting

Coloring and paint coating are carried out according to the process setting requirements.

Furniture painting job site

Finished furniture painting effect

On the basis of doing a good job in the pre-treatment of the coating substrate, the standardized requirements and management of each operation process is to empower high-quality coating.