I use these often for sanding my didgeridoos. I vary the grits from initial sanding after shaping to final sanding.
Here is link for flex-able sleeves. https://www.supergrit.com/3-x-9-sleeve.html
These sleeves will fit with minimal effort on these pool noodles. https://www.dickssportinggoods.com/p/big-joe-super-swim-noodle-23lnbusprswmndlxxwsr/23lnbusprswmndlxxwsr?sku=24215001&camp=CSE:DSG_92700072979560352_lia_pla-1746450544256_58700008023022506_71700000100235801&segment=&gbraid=0AAAAADv4bTa_KKmLZe2KExdjLU5eHV7co&gclid=Cj0KCQjwj_ajBhCqARIsAA37s0yKFHYBIvW6qskagWcAeGR55kT84GEVUvjepr1Cjxt-QGNPE9JIGmsaAv-oEALw_wcB&gclsrc=aw.ds
You MUST walk your work back and forth and DO NOT bear down or you’ll melt a soft spot in pool noodle. For a hobbyist on a budget this really works well for me.
As I put an epoxy coat on my didgeridoo I can even use the pool noodle with a lambswool covering turning it into a polisher.
See results for yourself on this link. This is a Century Agave Inflorescence turned into an awesome sounding didgeridoo.
https://www.facebook.com/photo.php?fbid=607385831434040&set=a.470144525158172&type=3&mibextid=DcJ9fc