I first saw this Spiked Pentakis Dodecahedron made with 60 Sonobe units on
Tom Hull's Model Gallery.
I made one of my own a couple of years ago and I thought I will share some hints with fellow folders.
More recently, I found out that the Sonobe Units were first assembled like this by Michael Naughton.
First make 60 Sonobe units of any kind - meaning, original
or variations of sonobe units.
Mountain and valley fold as shown in the figure below, i.e., mountain fold AC and AD and valley fold BC.
Pair up units and assemble as follows: Take two units, say X and Y. Insert tab 1 of X into pocket 1 of Y and
tab 1 of Y into pocket 1 of X to form one vertex of your pentakis dodecahedron. Make 30 such compound
units. Then assemble these into clusters of 5 to arrive at the finished model.
More details about this construction may be found in my book
Marvelous Modular Origami
The finished Pentakis Dodecahedron.