Make sure the silicone you are using is 100% silicone, not just caulking compound. Apparently the cure process is different for the two, and silicone will cure better and stronger. When I set the knot for my Dubl Duck M-2, I couldn’t find the tube of 100% silicone, so I used a tube of caulking that I had from a recent project. This morning I was shaking the water out of my brush, and the knot came flying off. Fortunately, all the old caulking was not cured, so I was able to wipe it right out. Once the knot dries, I will reset with 100% silicone. Whoops.
Epoxy sets hard and doesn't require air to dry like latex caulk. I've used Gorilla glue (not the two part epoxy) and don't like the way it expands as it sets. There may be applications but I avoid that product.
100% silicone seems to me too like it would probably work on setting a knot in a handle. I found that 100% marine silicone was the only glue product that was able to secure the upper brake light to my back window of my Jag XJ6 and have it survive the intense Florida heat and road vibrations. I had adhesion failures with every other epoxy product I tried.
I prefer silicone over epoxy, so I can remove the knot if possible. I hate the thought of someone 30 years from now not being able to save a vintage brush because they can't get the knot out.
