hi, this may be a daft question but what is the coating that you get on black bolts ( tuf neck stem bolts and the likes)
ive had some rusty bolts in lemon juice an they've come out like new - the black coating ,
i dont want to paint them as it chips off, i 'd like to have them recoated but not sure what it is or where you could get it done
or is there something you can buy to DIY which would be better for me.