Gillig renovation project in the early stages - help needed!

[gilligsnisland]

Hey BCM Forum!
This is my first post of what will likely be many. I'm helping my friend with some work on his Gillig transit. When removing the top layer of sheet metal from the walls, he noticed a white panel inside the wall (shown in picture) which appears to run around the bus under the top layer and is held in by rivets.

We're wondering:
1. the purpose of this panel
2. can it safely be cut without harming the structural integrity
3. does it in-fact wrap around the whole perimeter of the bus, under the top layer

Any help is greatly appreciated!
Thanks,
GilligsnIsland

[Bill Gerrie]

I would be careful in cutting it. I suspect it is a structural part to reinforce the body. On a GM the outside is aluminum with a steel band below the windows for structural strength. There is also a layer between the aluminum and steel to prevent them from contacting each other. This prevents corrosion. Aluminum and steel do not like each other. Electrolysis forms and corrodes the panels. If you need to connect any steel to an aluminum panel use duct tape to separate them. Of course not if it is an electrical connection.   

[Dave5Cs]

Looks like those two windows were put in after not original and that piece may have been added to carry the load across them. You might try some of the Gillig forums also or even schoolies.