Randy,
	IPC-L-108B and IPC-L-109B are the specifications that address laminate 
and prepreg respectfully.  However, I believe that they allowed 1 ply 
constructions prior to the military specification change.  I can't verify that 
since I don't have those standards at hand.  As for concerns about 1 ply 
constructions, not all one ply alternatives can match the thickness of the two 
ply core that it's replacing, and there will be a slight difference in 
electrical performance.  However, thickness variability will be better, and of 
course the cost advantage of the one ply.  You really shouldn't see any 
problems with voiding or measling unless the supplier has adjusted their 
process parameters to try to get a greater thickness.  Hope this helps.

Glenn Pelkey
Maxtek Components Corp.
(503) 627-2084

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