Aluminum Brass is an alloy added by Tinker's Construct created by smelting Copper and Aluminum in a Smeltery. The recipe is three Aluminum and one Copper (equates to two ingots of aluminum brass). You can place something (such as a Tool Rod) in a Casting Table, pour the liquid in, and create a cast. You can also do this by using Molten Gold.

Aluminum Brass Ingot