Cautionary Points When Repairing Aluminum Alloy Panels

CAUTIONARY POINTS WHEN REPAIRING ALUMINUM ALLOY PANELS




1. PORTIONS WHERE ALUMINUM ALLOY PANELS ARE USED

2. WORK SAFETY







Although aluminum is a nontoxic material, it is very light in weight, which can cause metal particles to easily become airborne during sanding. It is important for technicians to protect their lungs and eyes from these particles.
Being aware of the various dangers involved before starting a work and protecting your body by using the appropriate safety equipment is the personal responsibility of the technician. It is also necessary to provide adequate lighting and ventilating facilities in the workshop.
Please follow the recommended safety precautions when repairing aluminum panels.
- Always wear protective glasses, ear plugs, dust masks, and other protective equipment and protect your eyes, ears, and respiratory system.
- Make sure to wear protective gloves when conducting heat repairs, when sanding or using organic solvents.
- Always make sure the workplace is equipped with fire extinguishers, emergency blankets, first aid kits, and an eye washing area.




3. 5000 SERIES AND 6000 SERIES ALUMINUM ALLOY

HINT: There is a marked decrease in the panel strength if heated over the heating temperature limit.




4. CHARACTERISTICS OF ALUMINUM ALLOY
a. If the base metal of aluminum alloy is left untreated, it will naturally develop an oxide film that will protect against corrosion.
As a result, an anti-rust agent does not need to be used even when aluminum alloy is exposed to heat during shrinking.
b. Aluminum alloy conducts heat very well so a wide area will become heated when heat is applied to one area.
c. Aluminum alloy does not become magnetized.

5. CAUTIONARY POINTS WHEN CONDUCTING REPAIRS
a. If aluminum comes into contact with another type of metal (especially steel), galvanic corrosion will cause the base metal to corrode. As a result, the base metal will corrode if tools used to repair steel panels are not cleaned before they are used on aluminum alloy surfaces because they will leave behind steel particles.
Therefore make sure to completely clean off iron particles on the surface of tools if using them to repair steel parts before use or prepare a separate set of tools (hammers, dollies, chisels, air sander, etc.) for use on aluminum alloy only.

HINT:
What is galvanic corrosion
Rusting that is created by a potential difference is created between two metals that is produced when they are fixed together. This phenomenon occurs with any type of metal and aluminum causes the corrosion when the base metal surfaces of aluminum and steel are put together.

b. An oxide film forms on aluminum alloy within a matter of minutes when the base metal is exposed to the air.
This oxide film has a negative effect on putty and paint adhesion so it is important to immediately treat the base metal after sanding and degreasing.
c. Aluminum is brittle and easily develops work hardening and cracks. Heating aluminum when restoring a deformed portion improves workability and prevents work hardening and cracking so it is an effective method when repairing.
However, heating at the optimal heating temperature provides the very best results and any increase in temperature above this will result in a corresponding decrease in strength so it is important to make sure to keep the temperature within the optimal limit. (There is a marked decrease in strength if the optimal heating temperature is exceeded.)




6. CHOOSING THE REPAIR METHOD

7. THE WORK PROCEDURE OF EACH REPAIR METHOD




a. Repairing Using a Screw Puller.

NOTE: Make sure to completely clean off iron particles on the surface of the tools above if using them to repair steel parts before use or prepare a separate set of tools for use on aluminum alloy only (to prevent galvanic corrosion of the aluminum).

8. CHECK OF THE DAMAGE




a. Inspect visually and brush your hand across the damaged surface to determine the condition of the damaged area and whether there is any stretching. Also, check for any cracking and paint peeling. In cases where no paint defects are found, conduct the work starting from (10).

9. PAINT REMOVAL (NOT NECESSARY IN CASES WHERE ARE NO PAINT DEFECTS)




a. Completely remove the paint at the points where bonding chips will be attached.

10. DEGREASING WHERE THE BONDING CHIP WILL BE ATTACHED




a. After air blowing the surface, apply the degreaser cleaning solution that comes with the screw puller set to a cloth and degrease the area to be repaired.
b. If there are no paint defects present, scuff with the extra fine compound and then degrease.

11. PREPARING THE PLATE HOOK




a. Heat the plate hook with an Industrial heater gun and attach the bonding chip before it cools off.

12. SETTING THE PLATE HOOK




a Attach two-sided tape (or masking tape folded over on itself) on the back of the magnet for positioning and set the plate hook on the panel surface to secure it in place.
b. The magnet must be attached with tape because aluminum does not magnetize.

13. ATTACHING THE PLATE HOOK




a. Heat the bonding chip with an Industrial heater gun and use a handle of a hammer or the like to apply pressure on the plate hook and adhere it to the surface.
b. Next, air blow to cool down the panel surface and plate hook.

14. SETTING THE SCREW PULLER




a. Fasten the magnet rubber plate attachment under the arm of the screw puller (with tape or the like) to prevent secondary damage.
b. Attach the plate hook to the eye nut and then attach the screw puller hook to the eye nut. Pull out to about 1 to 2 mm past the height of the undamaged surface.

15. PULLING










a. Keeping the screw puller in the same pulling condition, lightly strike the convex surrounding area with a chisel or wood piece.

HINT: Repeatedly pull in the order of a - b - c in succession and restore to about 1 to 2 mm of the height of the undamaged surface.

16. REMOVING THE PLATE HOOK




a. After pulling, use an Industrial heater gun to heat the bonding chip until it melts and then remove the plate hook.
b. Heat the leftover bonding chip and use a spatula to quickly remove it from the panel and then apply the de-greaser cleaning solution to degrease the panel surface.

NOTE: After the above work has been completed, conduct the given shrinking work (the same as for repairs on steel panels) if the tension of the repaired panel surface is inadequate.

17. SHRINKING




a. Use a carbon electrode to shrink any heightened portions due to panel stretching to ensure panel tension.
b. Remove the burn mark after shrinking the same as when repairing regular steel panels.

NOTE:
- There is a negative effect on putty adhesion of the exposed panel portions due to oxidation.
- Create a featheredge on the previous coat, apply primer and putty immediately after the shrinking work.




c. Repairing with a Hammer and Dolly after Heating

NOTE: Make sure to completely clean off iron particles on the surface of the tools above if using them to repair steel panels before use or prepare a separate set of tools for use on aluminum alloy only (to prevent galvanic corrosion of the aluminum).

18. CHECK OF THE DAMAGE




a. Inspect visually and brush your hand across the damaged surface to determine the condition of the damaged area and whether there is any stretching.

NOTE: If one more of the two below can be applied to the damage, replace the panel.
- Plastic deformation and paint cracking on a bent portion are present.
- Kinks are present on the inner panel portion.
- Inner panel is broken away from the outer panel.

19. PREPARATION FOR HEAT REPAIRS




a. Cover the undamaged paint coating with a wet cloth so that it will not be burned by the flame of the burner while heating.
b. Apply the heat label 50mm away from the portion to be heat repaired (to prevent it from coming directly into contact with the flame of the burner).

20. HEAT REPAIRING







a. Heat the bent portion at an average temperature and stop heating when the optimal heating temperature has been reached. (Make sure the flame does not come into direct contact with the heat label.)

NOTE:
- Measure the painted surface when using a noncontact thermometer. (The aluminum base metal surface cannot be precisely measured.)
- Apply a guide coat or a lacquer coat (white or black) on the base metal surface and then measure the surface to be painted when measuring the aluminum base metal surface.
- The temperature will rise immediately after heating so make sure to frequently measure the temperature. (There is a marked decrease in strength if heated at a temperature over the heating temperature limit.)

21. REPAIRING BY HAMMERING




a. Rough repairing
Aluminum quickly cools down after being heating so hammer the underside of the panel with a plastic or wooden hammer immediately after heating.




b. Guide for when rough repairs are completed
Rough repairs are completed when the panel edge lines have been restored to the undamaged condition regardless if there is still surface unevenness present.




c. Repairing with a Hammer and Dolly
- Smooth the surface repeatedly using an on-dolly and an off-dolly on the surface.
- Restore the panel edge line with an on-dolly.

22. CHECK OF THE REPAIRED SURFACE




Check the given two areas and repair by shrinking using a carbon electrode if even one of the two apply.
- There is an area that is higher than the repaired surface.
- There is inadequate tension.

23. REPAIRING DENTS ON THE INNER PANEL PORTION




a. If there are no high points, repair by putty shaping.




b. Procedure if High Points are Found Hold an industrial heater gun close to surface and heat for about 30 minutes.




c. Repair the shape of the surface with a finishing hammer before the heated portion cools off.

HINT: Alternate between heating and hammering.

24. PROCEDURE FOLLOWING PANEL REPAIR (PUTTY SHAPING, PAINTING, ETC)




a. Conduct the procedure based on the work process. (The basic work process is the same as for repairs on steel panels)