I broke a harp string (e above middle c) and I was wondering if I could change it with a nylon guitar string if I wanted some immediate replacement (it could take a while to order new harp strings by mail).
Don’t get into the habit of improvising like this. Once you put a guitar string on the harp you’ll leave it there and do the same thing again. This is why harpists keep an extra set of strings on hand. If you call a place like Vanderbilt, you’ll have the replacement string in 2 days.