Aluminum Alloy Body Repair - Body and Frame Correction
1. Body and Frame Correction
Generally, the thickness of the core structural body parts (such as the frame) is 1.5 to 2 times thicker than those for a steel panel body.
During pulling correction of an aluminum alloy body, more resistance will be felt than for a steel panel body.
When an aluminum alloy body is collapsed by collision impact, the parts are easily cracked because of work hardening. If the parts are pulled as is, cracking will occur, making repair impossible. Therefore use aluminum’s elongation characteristics and pull the damaged area using a body and frame correction equipment while heating the aluminum parts being straightened.


Heating and Temperature Control of Aluminum Alloy:
When aluminum alloy is heated over 392 °F (200 °C), its elongation characteristics are improved. However its melting point is as low as 1184 °F (640 °C).
Heated aluminum does not change color like steel sheet. So there is no way to accurately judge the amount of heat input. Therefore, it is extremely important to carefully monitor the heating temperature by external means.
To accurately monitor and control the correct heating temperature, always use heat detection crayon or paint that changes color at 230 °F (110 °C).
1.
Apply heat detection crayon or paint about 25 mm (0.98 in) away from the border of the flame contact area shown in the figure with a width of about 10 mm (0.39 in).
2.
Always move the flame tip around. Do not keep it at a fixed point.
3.
Stop heating when the heat detection crayon or paint fully changes color.
4.
Restore the frame dimensions by pulling using a body and frame correction machine. Repeat this process as necessary.
5.
Be sure to check for cracks after the repair.