Phil, Why not cut this crack so it looks like an intentional V. That will give it clean edges. Then you can shape the opening if you want too. You could leave it at that or you could even lace it with something. I think that was a thought you already had.
I had a thought I wanted to ask you all about. How about if I was to smooth the crack all the way down widen it the top a bit to give it a visual "v" effect and use a red inlace for about the bottom inch and use a red marker or something bright red to highlight the insides of the gash and still use the vine as sort of a stitch/lacing from about an inch from the top to about an inch from the bottom.
Well it's Sunday, so maybe you've already done the piece. I like the idea. Would you drill the piece for the vine lacing. I don't see any prior reference to a vine. I realize it's an apple tree, but does the red have to be bright? Can you make an 'apple' red?
I actually don't have a preference for the tinting of the red ans long as it is red to sort of simulate a gash need stitching. I still intend to use the vine to lash/sew it up. No it is not done yet, too many other things in the way right
Phil,
Just a thought, I have used brass shavings/dust and CA glue, or mixed with epoxy, to fill cracks in plum. Looks like a vein of gold in the wood. Got the brass from Home Depot for free, it is the leftover residue from their key grinding machine. Lacing sounds interesting; if it is anything like caning a chair, you would need to soak the vine in hot water and a spoonfull of glycerine, to soften it.
Luck