There was a thread a while back about whether or not to apply head cement to the fly head.

I mentioned that I rarely, if ever, use it and do not have thread wraps coming loose.

Anyway, was reading "Hatches II" again and noticed, for the first time, Caucci and Nastasi saying this, while showing how to tie their Comparadun patterns:

"Important Tying Notes: Do not cement or lacquer head. It is not necessary and quite often the lacquer bleeds back to the dubbing affecting the buoyancy of the fly. Four or five jam knots will outlast the materials of any fly you can tie."

Page 313

Not sure that was in the original Hatches book. Will have to look again.