Don't - repair outer aluminum parts. (Replace outer aluminum parts)
As the use of aluminum in the manufacturing of vehicles has increases and we now find aluminum used as structural parts, technicians must learn new repair processes for them as well. Different types of aluminum are sensitive to heat. The way that aluminum responds to the pulling forces is also somewhat different than steel, and different tests and precautions must be used when repairing it.
Alloyed aluminum is grouped into two categories: heat-treatable and non-heat-treatable.
The heat-treatable group includes: 2000 series (alloyed with copper) used often for body panels; 6000 series (alloyed with magnesium), also used for body panels; and 7000 series (alloyed with both zinc and magnesium, making it very strong), used for applications such as bumper reinforcements.
Non-heat-treatable aluminum includes: 1000 series (nearly 99 percent pure), which is very soft and used for electrical wiring; 3000 series (alloyed with magnesium), used for interior structures; 4000 series (alloyed with silicon), often used for electrode welding wire; and 5000 series (alloyed with magnesium), often used for inner structural parts.
Don't- repair cracks in aluminum structural parts (Do replace the structural part)
Or risk driving with unsafe parts which can cause injury when involved in an accident.
Aluminums soften when heated, thus allowing technicians to repair collision-deformed aluminum more easily. Both heat-treatable and non-heat-treatable aluminum alloys may be heated to repair, but as with steel, these alloys may also be damaged with heat if the recommended temperature is exceeded.
Unlike steel, aluminum does not change color as it heats, thus making it nearly impossible to judge temperature by eye as the material is heated. Aluminum also has a critical temperature at which it "anneals" or permanently softens. This temperature is below its melting temperature, but above its repair threshold.
Don't - exceed recommended temperature to soften heat-treatable and non-heat-treatable aluminum alloys.
Technicians must be very diligent when using heat to repair aluminum to stay within the repair temperature limits.
Do - carefully monitor the temperature of the aluminum
Heating aluminum can be monitored using heat detection crayons, heat detection paint, heat monitoring strips, non-contact thermometers or thermocouples found as probes on a digital volt meter. Because of the high temperatures needed to reach the relatively low threshold (400-570 degrees F), careful monitoring should be observed.
Do - carefully detect the cracks
Cracks may be very small and difficult to detect, so repair technicians must use a dye penetrate to detect small cracks.
Do - make certain technicians are specifically trained to aluminum repair and are certified aluminum welders so they are able to test and inspect the repairs that they complete to assure their repair quality, and also in order to be aware of and be able to eliminate galvanic corrosion.
Technicians should be full trained on the basic physical properties of aluminum as well as be able to: