Strumming Techniques - The Thumb Strum
Strumming Techniques - The Thumb Strum by Robin Clark
Strumming with the thumb is an old traditional technique. It is mentioned in Jean Ritchies 'The Dulcimer Book' that includes old photos of her father and Ed Thomas who both look like they may be using the technique. Also 'thumbing' or 'thumping' is described by Bill Graves in this article:
With this technique the dulcimer plays slightly quieter and mellower than when strummed with a quill but it does give the melody a certain clarity.
Both Jean Ritchie and Bill Graves talk about using the fingers of the right hand on the dulcimer as a support. I find that this also helps to hold the dulcimer steady while strumming with the thumb.