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2

 Adopt sound insulating material to reduce the noise in the compartment.

For the heat, vibration and sound insulation of the body, they are a systematic engineering. Besides you

take measures on effectively improving the rigidity of the body and sealing technique, the following

measures can be taken in the body design and manufacturing:

a. Sound insulating material: paste a layer of asphalt board on the floor and FR/RR fenders. Add

insulation pads on the cowl and the floor.

b. Sound absorbing material: adopt formed carpet which is composed of front floor carpet and rear

floor carpet.

The FR/RR floor carpets are integrated with the floor and sound absorbing pad. It is required that the

floor and the pad will not peeled when torn by outside force.

3. Sealing

An elaborate concern is taken from design and manufacturing on the body sealing. Sealing is very important

for the operation performance of dust prevention, water proofing, corrosion prevention, heat protection, heat

preservation, noise reduction, etc. Especially, the floor and cowl are located in the harshest outside environment.

The mud splashing from road, dust and sand, wheel noise, engine noise and hot air will get in the interior

environment by every opening.

After the body assemble welding completes, apply a line of sealant on all joints of the body to avoid water and

vapor permeating into the metal joint and also to ensure the quality for the following painting.(Figure 5-25).

Besides, a layer of stone-strike proofing paint is applied on the bottom of the body. The paint has good sealing

effect. For the sealing of mounting parts on the body, traditional methods are generally adopted, such as

rubber sealing ring, cover, rubber strip, special-shaped sealing strip, etc. But in order to make more minute

and rigorous considerations in design and manufacturing of structural parts and the stability of the dimension

relationship of contacting sealing. For windshield and rear back door glass, a natural-curing high-tensile

sealant is adopted in sealing. It represents the advanced modern techniques in reliability and mounting technology.

5-25  

1.

 2.

 3.

 

Figure 5-39 Area Where Chloride Ethylene Plastisol Is Applied

1. Front Mud Guard 2. Rear Side Wall 3. Rear Wheel House

Front

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4. Surface Treatment Of Body

The consideration of the body surface treatment is very strict, careful and considerate. Although it is not

high-grade car, it is nearly the same with the high-grade car on the surface treatment.

1

1

1

1

1  Application of Galvanized Steel Plate

In order to prevent the steel plates from rusting, all outside punching parts are made by galvanized steel

plate.

2

2

2

2

2 Phosphatization

Phosphatization is also called pre-treatment of painting. After degreasing cleaning to the body, a layer of

zinc phosphate is applied on the body. The layer thickness is controlled less than 3µm, which can take

effect as the first protecting layer and also is favorable to adhesion of the coating used in the next step.

3

3

3

3

3 Cathode Electrophoresis

Electrophoretic painting shows its high efficiency and quality, safety, economy, etc. in actual application.

Four kinds of electrochemical phenomena (dielectric, electrophoresis, Electrodeposition, electroosmosis)

appear in the course. The feature and the advantage of cathode electrophoresis is multiply better than

anode electrophoresis. None is better than it and the technique management is also extremely strict.

4

4

4

4

4 Intermediate Coating

The intermediate coating is one located between the base coating (primer) and the surface coating. The

function is mainly to improve the flatness of the workpiece surface and the base coating and to create a

good base for top paint. The brilliance and fullness of the painting layer and the decorating effect of the

coating will be greatly improved.

5

5

5

5

5 Final Coating

The final coating on a vehicle is the last coating in multilayer coatings. It will directly influence the

decorating effect, weather resistance and the appearance of the vehicle. Choosing final coating is very

strict. Match, economy and operational easiness should be considered. The performance of all items can

reach the national and company standard. The appearance of the paint film is flat, smooth, plump, etc.

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6

6

6

6 Protecting coating for storage

When left in an open air for a long term (more than 3 months) or transferred by sea, a layer of water

soluble protecting wax should be applied on the surface of the body .Ultraviolet absorbing material is

added in the protecting coating. Clean it with detergent or fresh water before selling to make the brightness

of the painting reappear.

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Section 5 Painting Technique after Body Repair

Partial painting is needed when the vehicle crashes, parts rust, surface bubbles and color changes. The

painting techniques after repair are as follows:

I. Base Treatment (Pre-Treatment)

1. Peel the layer of painting and the coating on the panel.

2. Remove the edges and corners and polish the steel surface where painting peeled and the paint film at the

edges.

3. Cleaning and degrease. Clear up the dust and dirt and remove the oil, etc with degreaser.

II. Base Coating Procedure

1. Apply primer. Apple air drying type paint on the metal surface.

2. Air dry or heat dry (infrared drier) the primer.

3. Apply putty. Apply air drying type oil-base putty and Polyester-base putty on the panel surface that needs

repairing.

4. Air dry or heat dry the putty.

5.Manually polish the putty to make it smooth.

6. Manually polish with water to clear up tracks caused by sand paper.

7. Clear up the dust and the greasy dirt, and dry the putty polishing liquid.

8. Clean the greasy dirt on the polishing surface.

9. Use shield cover or paper to keep out the area that need not repairing.

III.Intermediate Coating Painting

1. Paint the second primer.

2. Air dry or heat dry.

3. Apply putty, and let it dry. Then look for sandhole or sand paper tracks.

4. Manually polish with water.

5. Clean it and let it dry by air. (The times of applying putty and polishing depends on the smoothness of the

surface)

IV. Preparation For Applying Final Paint

1. Shielding. Shield the area that needs not painting with paper.

2. Clear up the dust and degrease. Clear up the dust  and oil on the painting surface.

3. Toning. Mix paints to get the color the same with the final paint.

4. Mixing paints.

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V. Final Paint Applying

1.Apply final paint. Apply fast drying final paint for 3 or 4 times and synthetic resin paint for 2 or 3 times.

2. Air dry or heat dry.

VI.Polishing

1. After painting, you can polish with wax to remove the repairing paint shadow for decoration consideration.

2. Take off the shield. After painting, take off the paper, and clean the paint scattered on the other area.

3. Inspect the quality of appearance.