Heh... my aluminum backplated "distorted" when I tightened it to overcome the constant loosening that happened with it.

It bent then cracked.

Luckily I caught it before attempting to start the plane.... as I decided to take the cowl off to check something else...

Had I been in the line of fire for those metal fragements, well.... on this the plastic pieces would have caused less damage.

You can have problems with both materials as I found out the hard way.

Aluminum spinners are in no way immune to the same problems.