I have now installed all the cross-grain "cleats" on the underside of the soundboard. In a day or so when the last patch is well and truly dried I will put strings on the guitar and see if it holds together....... That's going to be nerve-racking.....
I haven't decided yet if I am going to attempt to re-finish the top, especially since I have suspicions that my guitar is going to crack further. While I'm thinking about that I'm going to "temporarily...." put pieces of low-tack clear plastic film, the type used to cover books, over the cracks & ding to stop dirt & moisture getting into them.
Tongdee & Vasavekkuli, thanks for the suggestion about repairing the ding. You were right that because the wood fiber's were broken that I wouldn't be able to get the ding out with water and heat. I think I will try one more time to remove the ding before I admit defeat.
Tongdee wrote:The lid drop ding has broken fibres in the wood. It can be repaired by carving out a slightly larger patch from a similar grained piece of similar wood
The crack above the fretboard (the left side) didn't close up and it's approximately 1.0 to 0.5mm wide. Once I find a bit of cedar that's close to the Western Red Cedar that the tops made of I will glue a sliver into the crack, and also patch the ding.
Working out how to mark the locations for the cleats was challenging. I cut a pencil and attached a piece of wire to the end and then bent it into a "U" shape. When it was inserted into the sound hole, my hand was then above where the crack was.
A co-worker lent me a video boroscope to look at the cracks with- it's didn't work as well as just using my inspection mirror and shining a flashlight onto it.
The suggestion posted by Dennis Tolz for using magnets to hold the patches worked FANTASTIC! I never would have thought of that. I also used the magnets to hold a steel-rule so I could take approximate measurements for the cleats.
I used scraps of balsa wood which were cut by trial and error down to the correct size for the cleats. I didn't find a successful way of putting glue on the cleats and not getting the glue smeared in the wrong spot on the soundboard as I adjusted the cleat into the correct location.
Thank-you for the helpful suggestions to repair my guitar.