What it is
Hareline Penetrator Hard As Hull Head Cement is a penetrating head cement made from acrylic copolymers. It soaks into thread and materials with low bulk, then dries in place to add durability. You brush it on where you want the wraps and tie-in points to lock down without building a thick, glossy head.
What to tie with it
Use it to lock thread wraps, especially down at the core where you want materials anchored before you cover them. It’s also handy for coating finishing wraps, sealing a wingcase, and for the all-purpose “cement as you go” steps during a build when you want penetration rather than a surface shell. Because it’s brush-applied, it’s easy to target small tie-off and tie-in areas without flooding the fly.
Flies and the fish they're for
This is the kind of cement you’ll reach for on wet flies, nymphs, and dries when you want a tough head and secured materials but don’t need a shiny finish. On trout and panfish flies, it’s commonly used to reinforce thread heads, wingcases, and key tie-in points that take abuse from teeth and rocks in rivers and stillwaters. It also fits right into streamer tying for species like bass and trout when you’ve got bulky thread work or stacked materials and want the wraps to penetrate and hold.
How it compares
Compared with Hareline Hard as Hull Head Cement, this Penetrator version is made to penetrate more deeply through thread and materials, while the standard cement has less penetration.