Well, the second time I bashed the motorbox, I decided to try the motorbox replacement kit, and I was impressed by how easy and straightforward it was.


First off, save the balsa bits that broke off so you can put them back in place when you put the box in.
The tools I used were:
X Acto knife
diagonal cutters
mini needlenose pliers
micro bar clamps
wife's emery boards
Epoxy- 30 min and 6 min
thin and thick CA
Debonder
pipette
kicker

You should have some scrap balsa in case you have to replace some balsa pieces.

Here's a pic of the plane with the front of the box removed.
Then with the rear of the box removed,
then, finally with the box completely out.


Use plenty of debonder to soften the CA and then gently pry the parts apart with your X Acto.
Use the diagonals to cut thru the thin parts of the ply so that you can take it out in small pieces.
DON'T FORCE ANYTHING, let the debonder do its job.
When you have it apart, cut the residual CA off of the parts in the plane so that the new box will fit.

Progress so far.