Quote Originally Posted by Geezer View Post
They both work...2" for up to 20mm, 4 inch for 26 and larger.
Pack them the same way you would make a knot fit into a regular handle. Use the glue that works for you. I used silicone (RTV) in very thin layers with a day between the layers. Silicone adhesives need a bit of humidity/ moisture to properly set. Some are colored.A bit of Bondo could help you set the height of the knot after it sets. The head needs to have the funnel...left after tearing the hair out... cut around to make it the right size for the knot. Use a part of the brush ferrule if you have a cheap brush to make the switch as in the 4" above.

And...Ed is the genius who was trolling us all....first!
Have fun!
~Richard
Wow, Richard! Those are unique brushes!