This great soft two-color blush brush uses standard 3/4" x 5" blanks. Simply turn one end of your blank down to where it just fits into the 15mm (3/4" blanks are 19mm square or round) tubed extension. Turn the rest of the handle to your desired shape and finish. Then glue the handle to your blank. Very simple and since you can use standard pen blanks, your choice of blank material is wide open.
More detailed instructions coming shortly.
Shown finished with a gecko acrylic blank.