The original was about that and a zinc alloy thinking it was made of aluminium I had it dipped in a hot caustic and there was a chemical reaction and it started to eat the alloy.
Caustic and ally don't mix, if you are lucky it just goes black, unlucky and it dissolves. You can dissolve the ally seat post out of a steel bike frame with caustic in a week and that's about 3/16 thick. Plenty of sob stories from people who put vintage cylinder heads in caustic to clean them...