: Bill -

: First, I'm not familiar with "HWM poly pads" and a quick Google
: search didn't yield much useful (that I could recognize, at least).
Always nice to know something that google doesn't: HMW Poly is High Molecular Weight Polyethylene. Think of it as a strong, dense, slippery plastic.
I'm not sure how Bill is using blocks or pads of this stuff, but it holds a woodscrew nicely. Two possibilities spring to mind. First is that he might use a long screw, putting it through a predrilled, oversized hole in the plastic pad, then driving the screw through the chine and on into the frame. That way the head of the screw doesn't maks direct contact with the wood. The plastic pad exerts clamping pressure over a larger area and prevents marring the surface. With no indentation from the screwhead, the screw hole is very small and easily filled or concealed. For many years people have use small blocks of wood for the same job. The plastic is slightly better than wood for this job. It won't stick to your glue, and won't split along grain lines like wood does. On the other hand, wood scraps are plentiful, and essentially free. Waxing them, or using a piece of wax paper, can keep the from sticking to any glue that might squeeze out. Using scraps of thin plywood eliminates splitting problems.
The HDPE (High Density PolyEthylene) Tom Yost uses for frames is roughly the same stuff. If you are making frames with it you'll have lots of oddsized scraps.

BTW, I don't want to sound critical, but now might be a good time to start teaching your daughter about proper safety in the shop. Floppy bunny ears are cute, but the strap was covering her eyes--and that can be dangerous. Why not get her a pair of child-sized overalls and make that her official outfit for carpentry?When she is ready to work, she changes into her work clothes. From a practical point, it is easier to get sawdust off of denim, than out of plush fur, too.
Hope this helps.
PGJ