Sandblasting aluminum to remove the imperfect parts is one way of fixing rust or other damage to the metal. Before sandblasting aluminum, it generally is a good idea to clean it to ensure all the imperfections are visible. There are many different sand grades, and picking the right grade will ensure the aluminum is not further damaged by the sandblasting. As someone sandblasts, he should keep moving and not remain on one spot, which could dig a hole in the aluminum. The aluminum also should be checked frequently — every few seconds — to ensure only the correct amount of sandblasting is done.
While it is possible to start sandblasting aluminum before cleaning it, this generally is not the best idea. If there is dirt or grime on the aluminum, it may hide further imperfections or create an optical illusion that makes the damage look worse. To get a proper idea of how damaged the aluminum really is, it should be cleaned beforehand with simple soap and water.
The sand that can be used in a sandblaster comes in many grades, which differ in thickness and abrasiveness. Sand should be picked according to how much work needs to be done and how damaged the aluminum is. Sandblasting aluminum with fine sand is best for small imperfections, while medium is better for larger imperfections. Large-grain sand is rarely needed and may be too harsh for even very damaged aluminum.
During sandblasting, it normally is best if the person moves back and forth and does not stay on one spot, even if there is only one spot that needs to be repaired. If someone sandblasting aluminum focuses on one area, then it will cause that section to wear away very quickly and may take away too much aluminum. Going back and forth also makes the sandblasting blend better and look more natural.
Keeping a sandblaster trained on a piece of aluminum for an extended period of time can make it difficult for the operator to know how well the sand is working, and it may cause him to sandblast too much away. This normally makes it best to turn off the sandblaster every few seconds — or minutes, depending on the size of the area being sandblasted. This allows the operator to see exactly how much work still is needed. As soon as the damaged sections are sandblasted away, the operator should stop, because further sandblasting at this point can lead to permanent damage.