Things You'll Need
Leather work gloves
Oxy-acetylene torch (with a torch tip size between "000" and "2")
550-degree prefabricated temperature crayon
Making aluminum shrink is a handy trick to master if you need to reduce the size of metal. Thin aluminum if often stretched wide to prefabricated lengths. The idea, according to Body Shop Business, is to make the aluminum thick again. The trick to shrinking aluminum is to heat the surface of the metal to encourage the molecules to move back into the hot area, thus reducing the size. Considering aluminum does not change colors when it is hot, purchase a temperature crayon at a home or auto body supply shop before shrinking.
Slide on a pair or leather work gloves, safety glasses and a dust mask to protect your skin, eyes and lungs.
Place your aluminum sheet onto a work surface. Fit an appropriate tip -- between size "000" or "2" -- to an oxy-acetylene torch. Ignite the torch.
Heat up a quarter-sized spot on the aluminum sheet. Hold the torch flame just off the surface for 30 seconds. Turn off the torch.
Touch the tip of a prefabricated 550-degree crayon to the hot spot at a 45-degree angle. Hold it for 10 seconds. Repeat steps 4 and 5 as often as necessary until the crayon turns orange. The 550-degree prefabricated crayon is designed to specifically correspond with the shrink temperature of aluminum. While not 550 degrees itself, the crayon will change colors once the tip reaches 550 degrees.
Hammer the aluminum with short, rapid strokes around the hot spot as soon as the shrink temperature is reached. Continue for 15 to 30 seconds. Avoid striking the hot spot directly to prevent additional thinning.