tgyee wrote:-
>   If you are talking about the voids at the PTH walls, one way is to dip
>     the PCB in a solder pot for a few seconds and then do cross-section
>     throught the solder in the PTH. Outgassing will occur if there is a
>     void, hence bubble is visible in the PTH solder. I tried this method
>     before, and find it very difficult to discover the bubbles because of
>     their small size. Anybody have a better method please let me know.
>
A quick and simple method is to use a hand soldering iron at 250 C and
fill the hole with solder. After the intial fizzing from the flux, the
solder should not outgas. Keep the iron on the hole for around 10
seconds to see if gassing occurs. Don't place the pwb on a flat surface
as this will give a false indication.

This is a pretty severe test and can be carried out at any stage after
plating.
--
Paul Gould
[log in to unmask]
Isle of Wight,UK

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