Copper isn't difficult to remove.
But most use aluminum for deciduous trees.
Most deciduous trees are fairly brittle after they have lignified. Try to develop the tree so you don't depend on wiring old wood.
The best are wired as they grow. Let the new branch extend 5 or 6 inches, then wire the green wood. Let it grow for about 3 or 4 weeks. Then remove the wire, and cut back to the first up/down set of leaves. Defoliate. When the buds start to grow, remove the bottom bud. Let the top bud grow to 5 to 6 inches. Rewire, bend down. Let it grow 3 to 4 weeks. Remove wire. Cut back same as before. Defoliate. Repeat as many times as your growing season will allow.
What you are doing is directing the new growth rather than trying to bend old growth.