[quote=QuiltnCowgirl]Ok - still new here to some techniqes so have to ask...why do you need to use paper, muslin or lightweight interfacing to make piano keys? TIA[/quote
The paper will be removed and makes for a more lightweight finish, similar to cutting away the under-fabric when you applique. Also the paper will not shift off grain and you will be able to make a straight piece to work with. I think that sewing onto fabric is fine too. There really is no right or wrong way! If you read through the topic link I think they discussed the pros and cons of it. It is a tutorial.
http://www.quiltingboard.com/t-56940-1.htm
I have never done it, but found I already had an old roll of adding machine paper. I wanted something wider to work with and by chance, found this in the paint dept. I thought I would let others know it, just because it was so cheap! KKitty