im with mike on the sinew being fine to get a smooth finish on your sinew,, but if it has been worked down too fine, you may have more glue in the mix than you might want, then the glue will be doing a lot more work than the sinew,,, so far from all the composites ive built , i realize their ma be a happy meadium between the two, i had a very old chinese horn bow and it was very smooth across the surface and it had sinew that was very large , the size of large spaghetti, and that was when it was fully cured, no telling how big it was when freshly put on.. i break mine down to a little bigger than pencil lead size when its dry then it swells when wet. let us know how it goes no matter what you do .james