Dad often uses a simple french cleat to hang indoor displays like the fish submarine. Basically, a board is ripped at a 45 degree angle and one side is mounted securely to the wall - the other to the display. When the sign is hung the angles interlock and keep the sign securely in place, tight against the wall and also level.
In this case, the sign is heavy (about a hundred pounds) and it is being mounted to a drywall surface. When dad designed the sign he put a recesses surface into the back to allow for the bracket and wiring. He cut two pieces of half inch plywood to shape and two french cleats (four pieces) at a 45 degree angle. One piece of plywood was glued and screwed to the sign, the other will be mounted to the wall in similar fashion. Then he levelled the display on the workbench and mounted the cleats using a level. He fastened the cleats to the wall plywood, making sure they fit into the sign properly.
Then he mounted the wall bracket securely upright in order to mount the display while he worked on it. Rather than laying the display flat we prefer work with the display sitting as it will when it is done. This way we can see how the lighting and shadows affect the colouring and shading we are doing. When dad is ready to mount the display he’ll remove the bracket from its temporary home and glue and screw it to the wall before mounting it permanently.
