I don't think there is an answer, even within a single brand of FR-4. As 
another illustrious member of this forum would say, "it depends!". What 
do you mean by carbonisation? Thermal discoloration is a result of 
carbonisation, oor do you mean going all black, crispy and flaky? And 
over what period of time? According to Mr Arrhenius, the speed of a 
decomposition reaction will vary according to the temperature; the 
converse is also true.

Brian

Wood, Kenneth wrote:
> Hey all...
> Does anyone know at what temp FR-4 carbonizes?
> I know the delam temp (Tg) but was asked to find this obscure
> bit of info.
> Thanks
> Ken
>  
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