Originally Posted by JermynStreet
Interested to know why, if you don't mind.
I have never had a problems lasting shell although very early on in my career I did have some shell tear quite drastically when blocking for boots.
But shell can be very irregular--you need two to three pieces to make a pair of shoes and it seems they seldom match up with regard to thickness or finish. Also shell has to be cut "just so" because it reflects light differently depending on how pieces, such as the vamp or quarters, are aligned on the shell.
You could blame the maker for cutting irregularities but the problems with varying substance and finish are either inherent in the nature of the product or on the tanner. That said, the only way for a maker to end up with any consistency is to buy large quantities of shell--futurities, essentially--and hand sort them.
It is my opinion that if the patterns are designed correctly, you don't need to draft (pull) a shoe very much to get it to go over the last. I have made cordovan shoes and the leather was stiff, but there were no tool marks left when I was done...anywhere.
And I don't use a tack to center the heel (as so many London makers do) so there's never a hole on the back of my shoes.