Tortoiseshell

[Geo Kloppel <geok@aol.com>]

Can anyone explain to me how tortoise shell laminations were fused to produce 
deeper sections than individual shells would permit? In the violin business 
this seems to have the reputation of a secret, the details of which are 
supposed to be known to very few people. Most have heard that heat and 
pressure are required, but I'm looking for more particulars than that (or 
perhaps a debunking?)