She has decided that segmenting so far is what she enjoys the most. The creative freedom to her adds to an otherwise mundane task of drill, turn, assemble.
Thick CA typically does the trick. We've had more than our share of explosions and have learned that certain sounds and feel during turning usually alert you before it happens. Stopping to flood the blank in thin CA and add clamps if necessary to pull it back tight if you've had a partial separation.
For direct wood-to-wood I like titebond wood glue. Just takes longer before you can turn it. I'm also not counting glue drying time in that time estimate above.
We've also been able to repair many of the blowouts as usually the failure happens between the metal and wood. Just clean the old glue out of the joint, sand again and re-glue.
On the metal segments, you have to make sure that you file the edges to remove all the burrs, or cut it big enough to keep the edges clear, and give it a good sanding to get any coatings or oils off the metal before gluing.
These pens were done with flashing from one of the big box stores, but we also use thicker metals from the craft stores on other pens. If we wanted thinner, a soda can would do the trick.