I was called out to attach a new sign to a pre existing sign but after looking at the sign currently in place I noticed that the two HDU panels had separated from each other on one side. Looks to be metal cross beams with routed out channel in signs, then glued back to back. From close inspection it looks like the glue never made contact with the opposing face as theres no smears or squeeze out, just a solid bead. Also no screws or brackets involved so I notified the business that if the remaining glue fails there's nothing stopping the two sides of their signs from just falling off. Question I have is whats the best way to fix this? Am i able to just clean out some of the debris between the two panels, gorilla glue, clamp and call it a day? Looking for any advice on this as i'm still relatively new in the HDU field. Also apologize in advance for the quality of photos attached... it was a negative windchill and wanted very badly to not be up on a ladder lol