I always just go with the Post-it note. How is it failing? is the post it note sliding down the ken? Or is it just not thick enough to hold the sara in place?
Cant hurt to try something a little stickier and thicker like medical tape or something similar, I have never tried this but it might work.
The majority of KendamaUSA kendamas are fixed together. Any that are labeled “Tribute” do not come apart. The Tributes have a hole drilled straight through both pieces with a small metal rivet that fixes the two pieces together.
The Tribute kendamas play great, the only difference you may notice is the ken will hang at a slightly different angle since the string is set straight through instead of at angled between the two pieces. this gives a slightly different pull but isn’t bad in any way. I have a few tributes and really like them!