All other isotopes of aluminium are radioactive. Probably the most stable of such is 26Al, with a 50 %-lifetime of 717,000 a long time: although it was present along with secure 27Al while in the interstellar medium from which the Solar System fashioned (believe to are already produced by stellar nucleosynthesis https://sheds-and-garages91233.yomoblog.com/44167187/5-simple-techniques-for-sheds-and-garages