Copper and tin have a few uses. Copper can be crafted into wires, with the ability to be insulated using rubber. Combinations of rubber and tin are used in making batteries.
The ores can be grounded using a macerator. By combining the resulting copper and tin dust in the crafting table with a ratio of three copper to one tin, one can obtain bronze dust, which can be smelted into bronze ingots. When you mix 3 Tin Ingots with 3 Refined iron Ingots and 3 Bronze Ingots, you get 2 Mixed Metal Ingots.
Copper and tin dust can also be crafted into Iron Dust Heaps, two of which will result in iron dust, which can then be smelted down into iron. A crafting recipe of this is (Where C=Copper and T=Tin.):
(Some elements of the recipe can be interchanged.)
Copper and tin are unable to make tools or armor without first being turned into dust. However, Copper and Tin can be crafted into Bronze, which is used in wrenches, armor, tools, and several others items. This recipe takes three copper and one tin.You can also make tin cans to store food to craft make a tall u shape with tin.