Question
I am one of the garden club sponsors at our high school. Two years ago we planted a Bloodgood var. of Japanese Maple in memory of one of our science teachers.  During the recent heavy midwest snow, a plow pushed heavy wet snow onto it. As the snow finally melted, my worst fears were confirmed:  one of the lower main branches split from the trunk.  The trunk is 2-3" in diameter.  The branch is 2" diameter. The branch is still attached where the lower portion meets the trunk.  It looks as if it would if someone were to stand on the branch causing it to rip from the trunk. When pressed together, the branch meets the trunk evenly, however, there is a small gap between the two. The internal sapwood, xylem & phloem layers are splintered.

My plan is to
1. use a very sharp knife to trim the splintered matter off of both the trunk & branch
2. Press both together and hold manually.
3. Apply grafting wax around edges to seal.
4. Wrap tightly with a tree wrap.
5. Support branch a v-notch.

I would appreciate your input.  Would like to get this done early next week when weather is above freezing.  Just have to find grafting wax.

Thank you.

Answer
I do not think that grafting this large a branch will work. When grafting we use fresh small branches (say about a pencil size). This branch may have dried out too much to get a good graft. BUT it maybe worth a try. The hardest thing will be supporting this size branch since the weight may pull the graft away from the trunk. Cutting the scion and parent straight is not the method that is used, Usually a wedge is cut so the scion fits into the cut. There are grafting rubber (large rubber bands) that are used to wrap the branch and this gives support and also helps keep in moisture. Use the grafting rubbers or grafting tape. Grafting rubbers are preferred. Begin wrapping at the base of the graft to secure the end of the grafting rubber by overlapping the first 2 wraps. Slowly work your way up the graft union overlapping as you go while keeping tension on the grafting rubber. This secures the scion in position. As you complete the last wrap, Secure rubber with a loop end of rubber under itself to secure

Here is a web link to grafting methods that may help. Check with nurseries for the wax and grafting rubbers.

http://extension.missouri.edu/publications/DisplayPub.aspx?P=G6971

IF all else fails you can always later just cut the branch off smooth and maybe the tree will sprout new growth on that side. Good luck with this project.