Before Starting Paint Repair - Determining Paint Finish and Compatible Repair Materials
1. Determining Paint Finish and Compatible Repair Materials
In paint repair, it is important to identify the old paint layer type and its state of deterioration. To correctly evaluate the old paint layer and decide on the type of paints to be used, follow these methods.

Visual Check

Check the surface appearance and level of polish.
Solvent Method

Wipe the paint film using a cloth wetted with lacquer thinner.
Thermal Method

Polish with P800 to P1000 sandpaper, and heat the sanded area with an infrared lamp to 176 °F (80 °C) or higher.
Quick Check Pencil Method

Press a flattened drawing pencil tip on the paint layer as shown. The hardness of the pencil which does not mar the paint layer identifies the paint layer hardness in the chart on the next page.





Old Paint Film Status by Judgment Method

Type of Paint Film
Judgment Method
Visual Check
Solvent Method
Thermal Method
Pencil Check
Melamine baked type
Granulated
Insoluble
No change
2H
Acrylic baked type
Finely granulated
Insoluble
No change
2H
Baked primer type
?
Insoluble
No change
HB?H
NC lacquer type
Polished
Soluble
No change
F?H
NC denatured acrylic lacquer type
Polished
Soluble
Slightly softened
B?HB
CAB straight acrylic lacquer type
Polished
Soluble
Softened
B?HB
Acrylic Urethane Type
Mirrored
Insoluble
No change
H?2H
Quick drying acrylic urethane type
Mirrored
Hard to be solved
No change
H?2H




Old Paint Film Status by Judgment Method:
Not all paint types can be used for paint repairs, depending on the condition of the old paint layers.
When the old paint layers are a baked or an acrylic urethane type that is not dissolved by lacquer thinner. Or if the old paint layers are totally removed, including the basecoat, lifting rarely occurs.
If the old paint layer is a lacquer type that is dissolved by lacquer thinner, lifting often occurs during paint repair.
For this reason, repair paint types are limited.
Types of top coat paint corresponding to old paint layers.

 
Baked type paint
NC lacquer
NC denatured acrylic lacquer
CAB straight acrylic lacquer
Acrylic urethane
Quick drying acrylic urethane
NC lacquer
?
?
?
?
?
?
NC denatured acrylic lacquer type
?
?
?
?
?
?
Acrylic urethane
?
?
?
?
?
?
Quick drying acrylic urethane type
?
?
?
?
?
?
CAB straight acrylic lacquer type
?
?
?
?
?
?

?: Can be used, but when primer-surfacer is applied, use the same type of paint

?: Can be used depending upon the condition, but select the right primer-surfacer

After deciding on the paint type to be used, confirm the below processes.

?: Required step

?: Optional step as needed