Where are you getting this info from? Have you tried stretching a typical silk thread?
My info comes from my own trial and error. Yes, I have stretched silk thread, silk cloth and sinew. The sinew stretches farther and maintains its elasticity better than silk will. However, there is more to it than that to be considered here. Most sinewed bows are nowhere near to working the sinew at its max. This bow is probably only using half the potential of the sinew. And I'm just guessing that based on the dimensions and draw. If that guess is remotely close, then the layer of silk is probably not overly strained either(not maxed out in elasticity). If that be the case then the silk probably is not effecting the sinew in this case. So I will concede the point on this one. Sorry Doobs, it would appear that I spoke out of turn here. However, I still maintain that this bow is a beautiful piece of work. Well done sir! Josh
In a lab type test silk actually stretches something like 3%. They used to pre-stretch the old silk backing strips in the pre-glass days so that the silk was under more tension and doing actual work.
Just laying it on top of sinew lets it be very inert and easily stretched, allowing the deeper sinew to still do its job. It would need to be something like low stretch glass cloth over the sinew to shut it down and make it act like a core instead of a backing.
I agree that the sinew could be working harder by inducing reflex during sinew application. Especially with TB glue.