I have the boiler of Rancilio S24 with the chrome coming off.

Do someone know what is beneath? Copper?

Is it dangerous to keep it like that?

Thank you

Hey Sergio,

Welcome to HB!

Raw copper boilers are quite common. The exposed copper will quickly form oxides (copper II or "Cupric" Oxide is black and the preferred oxide to have) that will be impervious and protect the boiler from any wear and protect you from any potential leeching of any potentially undesirable compounds into your boiler water.

The only risk is of the actual nickel or chrome coating flaking off and causing blockages in the plumbing. Once you're quite certain that you've got the loose stuff removed, you can proceed with reassembly.

Cheers!

- Jake

I have a big S-20 and the boiler on that was chromed on the outside but I did a rebuild and during descaling, it all came off. The boiler is basically copper, but it'll self-oxidize a bit and be a dark brown on the outside, which isn't a problem, it won't rust. I have mine under an insulating blanket for heat retention and it's fine, plenty of material to keep it healthy.