Poh--the oxidation/corrosion that has built up on those boards is probably
pretty extreme, but you have in investment in them and would like to
recover as best you can.

Tim Crawford, our Materials Group Lead, suggests that some saponifiers can
do a fairly effective job of removing those surface oxides. One material
our process engineers have used in the past was from a company called LONCO
and the saponifier was called LONCOTERG (probably an acronym from LONCO and
DETERGENT.) Another material we have had success with related to this issue
is Church and Dwight Armakleen. Just try cleaning with your most active
saponifier you have access to. If that doesn't restore solderability enough
to meet your needs, you may need to go through a process that will
essentially retin the solderable surfaces on your boards. To do this, try
the following steps.

1) bake as you have done (this will actually increase surface oxides, but
you NEED to get the moisture out of the boards
2) run bare boards across wave (dynamic is best) using a VERY active flux;
depending on severity of oxidations, and hopefully having good soldermask
still on the board, you may have to flip the board and run the other side
across the wave also.
3) CLEAN!!
4) go through normal assy process fairly soon thereafter




>I have a serious problem on some of the board that stucked in the store.
>All of them is at least 2 years.
>When I  wave-soldered the bare board, it has a lot of blow-holes, solder
>balls, pin-holes.
>
>Anyway, I try to purge all of them, but there are 6000 pieces in the Store.
>
>I try to bake at at 100 deg. C for 4 hours. Too bad, it doesn't work.
>
>I try to bake for any 4 hours just before wave-soldering. The result is
>terrible. Not even a slight Help !!!
>
>Can anybody give me some advises what should I do ???
>
>Thanks in Advance
>
>Poh ..
>
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***ALL NEW EMPF PHONE NUMBERS***

Jack Crawford, HelpLine Coordinator
Electronics Mfg. Productivity Facility
****NEW--317.655.3688
****FAX  317-655-3699
714 N Senate Ave, Suite 100
Indianapolis IN  46202-3112
VISIT OUR HOME PAGE AT: http://www.empf.org
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