Aluminum isn't really a heavy metal, but take it.
Melting 1,000 Cans To Cast An All-Aluminum Electric Guitar

Because dream it and (with enough cans and a recycling center paying 5¢ apiece) you can achieve it, this is a video of luthier Burl of Burls Art crafting an all aluminum electric guitar after melting some 38-pounds of aluminum cans (over 1,000) to cast the neck and body. My body? My body should also be cast — in bronze. “Or into the sea.” Yes, or into the sea.

Thanks to my dad, who agrees that guitar should only be used to play metal.