The front panel on the seat that surrounds our fireplace has fallen off. It is made of slate; about six inches wide; 8 feet long and perhaps a half inch thick. It is quite heavy; I'd guess 40 pounds or so.
The slate hangs vertically attached to wood with some type of adhesive. Looks like it has been repaired before since there is both white and black adhesive attached to the wood.
What type of adhesive would be best in this situation? Do I need to remove the old adhesive or just put the new adhesive in other spots along the back of the piece. I've got C-clamps to attach until it is dry.