I think that part of the reason my wood has been splitting when I bend it is that I do not have a bending strap. The bending strap keeps the wood on the outside of the bend from stretching, and so prevents it from splitting.
Here is the theory. You heat the wood to make it flexible for bending. The fibers in the wood become flexible when hot. It is the heat in the steam that makes the wood flexible, not the water. The steam helps because it keeps the wood from drying out as you heat it, but it is the heat that makes it possible to bend the wood, not the water.
When the wood is hot, the fibers of the wood become more compressible. They do not become more stretchable. Even when hot, if you stretch the wood the fibers will split apart. So the ideal situation when bending wood is to direct all of the movement into a compression. Here are some diagrams to illustrate the point.
This Wood Will Split When Bent
The wood in the figure shown above is being bent with no support on the outside of the curve. The fibers on the outside of the curve will be stretched by the force, so they are likely to separate and split.
A bending strap is usually a thin, flexible stainless steel sheet with blocks installed on the ends so that the length of the strap between the blocks is exactly the same length as the wood that is to be bent. When the wood is placed between the two end blocks and forced into a curve, the wood cannot increase its length, so the outside curve cannot stretch. All of the movement is forced into a compression on the inside of the curve, as shown below.
The Strap And End Blocks are Black
Because the wood is captured between the blocks on the ends of the strap, it cannot stretch, so all of the movement is translated into a compression on the inside of the curve, and the wood does not split.
So I went looking for something that I could use for a bending strap. A stainless steel sheet that is 3 1/2" by 48" was not available anywhere. Every hardware store that I asked said that they had nothing like that. One independent hardware store sent me to Woodcraft® since they specialize in wood working equipment. I looked there and at Rockler® as well, and alas, all of the commercial bending straps are piddly little 1" wide things for bending canes and walking sticks etc. None of them had anything like what I was looking for.
I ended up back at the Big Box store, where I found this.
An Emergency Towing Strap
This is nylon, so it will be stretchy. But if it can tow 7000 pounds, how stretchy would 48" of it be? And even if it does stretch a bit, wouldn't that be better than having no strap at all?
I unwrapped it from the plastic, and this is what it looks like.
The Towing Strap Unwrapped
That is a mongo piece of nylon. The strap is only 2" wide, but if I doubled up two lengths of it side by side, that would make a 4" strap, which would be just the right size. All I need to do is figure out how to mount some end blocks on the two straps that are exactly 48" apart and get it connected to my bending jig. It is something to think about.
Also, since this is a slow day, I thought that I would mention a pet peeve of mine. When I buy my wood at the store, it has UPC stickers on it that are glued on with stuff that is stronger than the glue that holds on the soles of my shoes. Getting those stickers off is a real pain in the neck.
I pick at it forever, but the label just comes apart and leaves a horrid, sticky residue that cannot be removed. You would think that when selling hardwood they could make the stickers removable so as not to mar the surface of the wood like that.
Peeling Off The UPC Stickers Is a Pain
I even tried using a dull utility knife to do this. Nothing makes it any easier.
Scraping With a Knife is No Easier
A pain in the neck!. That is it for today. I didn't get any real work done, but I have some enhancements to consider for my bending equipment.
