As we know the armour against cannon in SimplePlanes is next to none. No matter how thick the fuselage used is, it will likely not even survive a single shot from a cannon. Even stacking the fuselages ends up exploding in a chain causing everything to be damaged. So it "isn't" quite possible.

I did an test 8 hours prior to this post. I was using 4 layers of fuselage sandwiched together and a thick layer of glass which I set the health to zero. I was using a 150mm cannon which I set the muzzle velocity to 1250m/s and the projectile to "basic" instead of "explosive". I went to do the test. I fired the cannon at the "composite" piece I've built. It survived two or three of my shots. The glass managed to stop the projectile and not explode. It instead pushes forward toward the direction of the projectile or it shatters after receiving a few shots.

Unlike fuselage, glass actually shatters instead of exploding like normal fuselage. The explosion of the normal fuselage actually causes the other part to damage or explode too like a chain reaction.

We can conclude that glass is better as an armour than normal fuselage. It acts like a NERA (Non-explosive reactive armour or non-energetic reactive armour).