We have spotted other sign companies using a cheaper “composite aluminium” for their school signs, we disagree with this practice due to the safety of the materials.
Composite aluminium is made up of a layer of composite plastic sandwiched between two thin aluminium sheets. The danger to school children is that the aluminium is sharp on the edges.
We always put safety first when recommend material for school signs. We use solid aluminium for our school signs, and we also round any sharp corners for safety. Solid aluminium also ensures a longer lasting sign.