Fer fucks sake some people are stupid.... 2024-T4 and 6061-T6 are two of the most common alloys used in kit aircraft today, and are readily available in many forms at affordable prices. The more modern 6061-T6 alloy is a very versatile alloy for aircraft construction, providing superior corrosion resistance, good formability (easy to work with), and flexibility and strength.

Composition of Aluminum Alloys Alloy 6061-T6 2024-T4 Copper 0.25 4.50 Silicon 0.60 Manganese 0.60 Magnesium 1.00 1.50 Chromium 0.25 Above indicates percentage of alloying elements in addition to pure aluminum. Temper (-T) Designations -T6: Solution heat treated and artificially aged -T4: Solution heat treated