I started in the upholstery trade in the early 60's and used to encounter vast amounts of kapok. It was used as pillow and cushion stuffing and fill in padding on furniture. It has mostly been replaced with foam, dacron and polyester over the years. Often the kapok was mixed with down as a less expensive filler material. What I remember most about working with this substance was how it would float around the room and get in my nose, hair and eyes. It is a messy material to work with. I can imagine it would be a good dubbing material if one could control it and keep it from floating away. Also a little would go a long way. I would imagine a couple of pounds would last a lifetime. Jim