My experiments with the shrink wrap for bending have been yielding interesting results that I think are worth sharing. There have been a few times that I've had some splitting happen to green bows, but not the kind I'm used to. It isn't the sort of letting go that I've seen before, where a small bit lifts up and it spreads to a larger break. These look more like the wood is pulling itself apart with small breaks that are perpendicular to the bend. I think that perhaps leaving the plastic in place after the bend until the wood cools is giving the wet/hot/stressed wood a chance to pull apart. Today, I bent a C arm, and really took my time on the second bends just to see how long the heat really kept the wood limber and it worked like a charm, but then, I cut open the plastic to let the heat and moisture out and the bend stayed perfect, and I mean perfect.
This log I've been working on has been questionable during bends, but this bend was ideal. I am going to do some more samples to see how long I really have to complete the bend with this process. Stay tuned for the results.