Spruce top cupped...how to flatten

[Frank Capo]

I am repairing an otherwise nice Gibson B25 12 that sustained a collapsed fingerboard tab.

I understand how to deal with the cracks along the tab, a few lose braces and deformed plywood bridge plate. I removed the plate, bridge and the adj hardware.

The problem that I need advice on is a cupped area of the top, basically forming a 3 inch C on the mid to upper left of the sound hole where a brace let go. It is about 1/4 inch deep. If I clamp it dry it surely will crack, so I think I must wet, steam or heat it first... I appreciate advice on how to do this. Thanks.

[Glen H]

I'm not sure I follow, but wouldn't the cupping be removed if you put the brace back in place?  How do you know it will crack?  Maybe a picture would help.

[Frank Capo]

Glen. Thanks for the courtesy of your response. I think the wood needs to be humidified or dampened before I try to flatten it and reattach the brace. Unlike the bridge area, the cupped area does not seem so compliant when I press on it. I have a sponge in a tray and the sound hole covered to see if the top will take one moisture, and will give t a few days. Then i may even later apply a wet paper towel on the caul when I attempt to clamp it down. Thanks.

[William F.Eden]

Frank just put a hot damp cloth on the inside were it is Cup. and leave it for a day  then clamp it up inside with a piece of plywood that you have heated and another cull on the outside that is not heated leave it over night.Bill............

[Frank Capo]

Bill. Thanks. I was thinking that heating and then cooling while clamped must be involved in the process to get the wood "memory" reprogrammed.