I remember awhile back someone explained a method of repairing hairline drywall cracks with caulking. If the joint is solid but cracked from settling, I believe the trick was to "V" out the crack, fill in with flexible acrylic caulking, then mud over top of that. Is anyone familiar with this?
you are correst sir. You need to did out the crack so when you install the material there is enough space there to get a good amount of material in there. Problem is if you mud over the caulking, they will expand and contract at different rates and you will probably show cracks soon enough. I would dig it out and just use some dura bond and a finish.