There is no IPC specification requirement for storage of PWB, and lenght 
of storage.  We have done a couple of studies about storage (IPC-TR-462) 
which looked at solderability over a 2 year storage condition.  
Essentially this study concluded, that if you had good solderabilty to 
begin with and solder coating, and relatively benign storage, you could 
solder well after 2 years.  I don't know how to extrapolate this to 3-4 
years, but I believe the same conclusions would hold.  We have also 
studied the literature on steam aging of components, and have done round 
robin testing on this as well.

Regards
***************************************************
David W. Bergman, Technical Director
IPC
2215 Sanders Road
Northbrook, IL  60062-6135
708-509-9700 x340 Phone
708-509-9798 Fax
email  [log in to unmask]
***************************************************



On Tue, 29 Aug 1995 [log in to unmask] wrote:

>      WE NEED TO KNOW IF THE IPC MANUALS SPECIFY SHELF LIFE OF 
>      RAW PC BOARDS (AND ANY OTHER PARTS). CAN BOARDS BE 
>      SUCCESSFULLY SOLDERED AT 3-4 YEARS OLD? ANY HELP ON THIS 
>      WOULD BE GREATLY APPRECIATED.
>      
>      GLORIA 
>        
> 
>