I tried some nail polish but it isn't as hard as I had hoped.
Maybe the polish isn't the good stuff you all used, but I can dent it with my fingernail, and a little bit of clenching is going to remove the polish.
For comfort and performance, I prefer the twine rapping on the OD williamsburg, but prefer the polish on the small Old German Clay pipes.
I'll try the silicon tape after the polish wears out. I have high hopes for the silicon.
Experiments with the painted pipes:
On one attempt, I painted a with a very thick coat, added a thin coat or two the next day.
On one I added a single coat per day for a few days then leave it sit about a week (because I forgot about it).
One where I coated it thick with multiple coats and waited a day or two before smoking.
They all take a dent from my fingernail, and feel about the same in hardness.
That stuff can take a while to cure. Try multiple very thin coats over a few days.