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REPAIR

REPAIR

COATING METHOD FOR PP BUMPER

Process No. Process name Job contents
1

Bumper mounting

Set the bumper on paint worktable if required. Use paint worktable conforming to inner shape of bumper when possible.



1. Bumper

2. Set bumper section


2

Masking

Mask specified part (black base) with masking tape. Use masking tape for PP (example, Nichiban No. 533, etc.).

3

Degreasing, cleaning

Clean all parts to be painted with white gasoline, normal alcohol, etc. to remove dirt, oil, fat, etc.

4

Primer paint

Apply primer one to all parts to be painted, using air gun. Use primer (clear).

5

Drying

Dry at normal temperature [10 to 15 min. at 20°C (68°F)].

In half-dried condition, PP primer paint is dissolved by solvent, e.g. thinner, etc.

Therefore, if dust or dirt must be removed, use ordinary alcohol, etc.

6

Top coat paint (I)

Solid color

Metallic color

Use section (block) paint for top coat.


• Paint in use (for each color):

Solid paint

Hardener PB

Thinner T-301

• Mixing ratio:

Main agent vs. hardener = 4:1

• Viscosity: 10 — 13 sec/20°C (68°F)

• Film thickness: 35 — 45µ

• Spraying pressure: 245 — 343 kPa

(2.5 — 3.5 kg/cm 2 , 36 — 50 psi)


Use section (block) paint for top coat.


• Paint in use (for each color):

Metallic paint

Hardener PB

Thinner T-306

• Mixing ratio:

Main agent vs. hardener = 10:1

• Viscosity: 10 — 13 sec/20°C (68°F)

• Film thickness: 15 — 20µ

• Spraying pressure: 245 — 343 kPa

(2.5 — 3.5 kg/cm 2 , 36 — 50 psi)


7

Drying

Not required.

Dry at normal temperature [10 min. or more at 20°C (68°F)].

In half-dried condition, avoid dust, dirt.

8

Top coat paint (II)

Not required.

Apply a clear coat to parts with top coat paint (I), three times, at 5 — 7 minutes intervals.


• Paint in use:

Metallic paint

Hardener PB

Thinner T-301

• Mixing ratio: Clear vs. hardener = 6:1

• Viscosity: 14 — 16 sec/20°C (68°F)

• Film thickness: 25 — 30µ

• Spraying pressure: 245 — 343 kPa

(2.5 — 3.5 kg/cm 2 , 36 — 50 psi)


9

Drying

60°C (140°F), 60 min. or 80°C (176°F), 30 min.

If higher than 80°C (176°F), PP may be deformed. Keep maximum temperature of 80°C (176°F).

10

Inspection

Paint check.

11

Masking removal

Remove the masking in process No. 2.



REPAIR INSTRUCTIONS FOR COLORED PP BUMPER

Note

All PP bumpers are provided with a grained surface, and if the surface is damaged, it cannot normally be restored to its former condition. Damage limited to shallow scratches that cause only a change in the lustre of the base material or coating, can be almost fully restored. Before repairing a damaged area, explain this point to the customer and get an understanding about the matter. Repair methods are outlined below, based on a classification of the extent of damage.


Minor damage causing only a change in the lustre of the bumper due to a light touch

Almost restorable.

Process No. Process name Job contents
1

Cleaning

Clean the area to be repaired using water.

2

Sanding

Grind the repairing area with #500 sand paper in a “feathering” motion.

3

Finish

Resin section

Coated section

Repeatedly apply wax to the affected area using a soft cloth (such as flannel). Recommended wax: NITTO KASEI Soft 99 TIRE WAX BLACK, or equivalent.

Perform either the same operation as for the resin section or process No. 18 and subsequent operations in the “3)” section, depending on the degree and nature of damage.

Polish the waxed area with a clean cloth after 5 to 10 minutes.



Deep damage caused by scratching fences, etc.

A dent cannot be repaired but a whitened or swelled part can be removed.

Process No. Process name Job contents
1

Cleaning

Clean the damaged area with water.

2

Removal of damaged area

Cut off protruding area, if any, due to collision, using a putty knife.

3

Sanding

Grind the affected area with #100 to #500 sand paper.

4

Finish

Resin section

Coated section

Same as Process No. 3 in the “1)” section.

Perform Process No. 12 and subsequent operations in the “3)” section.



Deep damage such as a break or hole that requires filling

Much of the peripheral grained surface must be sacrificed for repair, and the degree of restoration is not really worth the expense. (The surface, however, will become almost flush with adjacent areas.)

Recommended repair kit: PP Part Repair Kit (NRM)

Process No. Process name Job contents
1

Bumper removal

Remove the bumper as required.

2

Part removal

Remove the parts built into bumper as required.

3

Bumper placement

Place the bumper on a paint worktable as required.

It is recommended that contour of worktable accommodate internal shape of bumper.


(1) Bumper

(2) Set bumper section

4

Surface preparation

Remove dust, oil, etc. from areas to be repaired and surrounding areas, using a suitable solvent (NRM No. 900 Precleno, white gasoline, or alcohol).

5

Cutting

If nature of damage are cracks or holes, cut a guide slit of 20 to 30 mm (0.79 to 1.18 in) in length along the crack or hole up to the bumper’s base surface. Then, bevel or “vee-out” the affected area using a knife or grinder.


(1) Paint surface

(2) PP base surface

(3) 20 — 30 mm (0.79 — 1.18 in)

(4) 3 mm (0.12 in)

6

Sanding (I)

Grind beveled surface with sand paper (#40 to #60) to smooth finish.

7

Cleaning

Clean the sanded surface with the same solvent as used in Process No. 4.

8

Temporary welding

Grind the side just opposite the beveled area with sand paper (#40 to #60) and clean using a solvent.

Temporarily spot-weld the side, using a PP welding rod and heater gun.


(1) Welded spot (Use heater gun and PP welding rod)

(2) PP base surface

(3) Beveled section

Note
• Do not melt the welding rod until it flows out. This results in reduced strength.

• Leave the welded spot unattended until it cools completely.


9

Welding

Using a heater gun and PP welding rod, weld the beveled spot while melting the rod and damaged area.


(1) Melt hatched area

(2) Welding rod

(3) Section

Note
• Melt the sections indicated by hatched area.

• Do not melt the welding rod until it flows out, in order to provide strength.

• Always keep the heater gun 1 to 2 cm (0.4 to 0.8 in) away from the welding spot.

• Leave the welded spot unattended until it cools completely.


10

Sanding (II)

Remove excess part of weld with a putty knife. If a drill or disc wheel is used instead of the knife, operate it at a rate lower than 1,500 rpm and grind the excess part little by little. A higher rpm will cause the PP substrate to melt from the heat.


Sand the welded spot smooth with #240 sand paper.

11

Masking

Mask the black substrate section using masking tape.

Recommended masking tape: Nichiban No. 533 or equivalent

12

Cleaning/

degreasing

Completely clean the entire coated area, using solvent similar to that used in Process No. 4.

13

Primer coating

Apply a coat of primer to the repaired surface and its surrounding areas. Mask these areas, if necessary.

Recommended primer: Mp/ 364 PP Primer

Note

Be sure to apply one coat of primer at a spraying pressure of 245 to 343 kPa

(2.5 to 3.5 kg/cm 2 , 36 to 50 psi) with a spray gun.


14

Leave unattended.

Leave the repaired area unattended at 20°C (68°F) for 10 to 15 minutes until primer is half-dry.

Note

If dirt or dust comes in contact with the coated area, wipe it off with a cloth impregnated with alcohol. (Do not use thinner since the coated area tends to melt.)


15

Primer surfacer coating

Apply a coat of primer surfacer to the repaired area two or three times at an interval of 3 to 5 minutes.

Recommended surfacer:


• UPS 300 Flex Primer

• No. 303 UPS 300 Exclusive hardener

• NPS 725 Exclusive Reducer (thinner)

• Mixing ratio: 2: 1 (UPS 300: No. 303)

• Viscosity: 12 — 14 sec/20°C (68°F)

• Coated film thickness: 40 — 50µ


16

Drying

Allow the coated surface to dry for 60 minutes at 20°C (68°F) [or 30 minutes at 60°C (140°F)].

17

Sanding (III)

Sand the coated surface and its surrounding areas using #400 sand paper and water.

18

Cleaning/

degreasing

Same as Process No. 12.

19

Top coat (I)

Solid color

Metallic color

Use a “block” coating method.


• Recommended paint:

Suncryl (SC)

No. 307 Flex Hardener

SC Reducer (thinner)

• Mixing ratio: 3: 1

Suncryl (SC) vs. No. 307 Flex Hardener

• Viscosity: 11 — 13 sec/20°C (68°F)

• Coated film thickness: 40 — 50µ

• Spraying thickness: 245 — 343 kPa

(2.5 — 3.5 kg/cm 2 , 36 — 50 psi)


Use a “block” coating method.


• Recommended paint:

Suncryl (SC)

No. 307 Flex Hardener

SC Reducer (thinner)

• Mixing ratio: 3: 1

Suncryl (SC) vs. No. 307 Flex Hardener

• Viscosity: 11 — 13 sec/20°C (68°F)

• Coated film thickness: 20 — 30µ

• Spraying thickness: 245 — 343 kPa

(2.5 — 3.5 kg/cm 2 , 36 — 50 psi)


20

Leave unattended.

Not required.

Leave unattended at 20°C (68°F) for at least 10 minutes until the topcoated area is half-dry.

Note

Be careful to keep dust or dirt from coming in contact with the affected area.


21

Top coat (II)

Not required.

Apply a clear coat three times at an interval of 3 to 5 minutes.


• Recommended paint:

SC710 Overlay Clear

No. 307 Flex Hardener

SC Reducer (thinner)

• Mixing ratio: 3: 1

Suncryl (SC) vs. No. 307 Flex Hardener

• Viscosity: 10 — 13 sec/20°C (68°F)

• Coated film thickness: 20 — 30µ

• Spraying pressure: 245 — 343 kPa

(2.5 — 3.5 kg/cm 2 , 36 — 50 psi)


22

Drying

Allow the coated surface to dry at 20°C (68°F) for two hours or 60°C (140°F) for 30 minutes.

Note

Do not allow the temperature to exceed 80°C (176°F) since this will deform the PP substrate.


23

Inspection

Carefully check the condition of the repaired area.

24

Masking removal

Remove the masking tape applied in Process No. 11 and 13.

25

Parts installation

Install the parts on bumper in reverse order of removal.

26

Bumper installation

Install the bumper.