Force

• Exerting force onto the aluminum will usually return the metal back to its original shape. Depending upon how thick the aluminum is, you may need to get some pretty heavy machinery to bend the metal back to its original shape. Most of the time, a large wooden mallet can be used, but you may need to get a sledgehammer in order to bend the thick metal back into place. You can also use your heal to put pressure onto the aluminum in order to force it back into place. When exerting exorbitant amounts of force onto anything, it is always smart to anchor down the object before doing so. This can be done using an anvil, weights or clamps.
  
  

Heat

• Another remedy for warped aluminum is heating it up and bending it with thick, metal tongs. As with other remedies, depending upon the thickness of the aluminum, varied amounts of heat can be applied. Be careful as reheating any type of metal reduces its strength over time.
  
  

Causes

• Along with heat and force, sandblasting is the most common cause of aluminum warping. Sandblasting is used to clean the aluminum, giving it its natural shine back. Sandblasting can take nearly everything off of aluminum, but if you are not careful you will be taking the aluminum off along with the debris. As the aluminum is blasted, the metal's natural protecting oils are diminished. With these reduced amounts of oil, the aluminum easily is attacked by moisture and air. This is what warps the aluminum. The problem is that most of the time the naked eye cannot see the aluminum oils dissipating, and if you do it is more than likely too late.
  
  

Prevention

• The easy way to prevent aluminum warping is to polish the aluminum with metal oil to maintain a strong exterior. Depending upon how often you clean the aluminum and how often the aluminum is attacked by the elements, you need to oil the aluminum at least once per year. With proper maintenance, your aluminum siding, roofing, car or boat will be around for a very long time.