Question, What are the back panel boxes usually made out of?

[0igo]

Also are they made from a single sheet? because i never see visible screws on the sides of them.

If there is a supplier that sells them in northern california, can i get a link or number please. thank you. (its for an indoor sign and just the back panel not the channel letters)

 

[Billct2]

Usually fabricated in house. A sheet metal shop could bend them up for you.

 

[DirtyD]

That is probably just 2" aluminum square tube mitered on the corners and welded with a sheet of ACM with Lords or VHB's on, it could also be aluminum angle as well, but it could also just be aluminum sheet broke into a pan box. There is a few ways to do it