I have been using ferric to etch boards for a while now. Recently I got lucky and came into a cache of 1973 vintage copper clad PCB stock, which will enable me to make some reproduction pieces that are pretty much indistinguishable from originals in terms of look. However, I have noticed that the ferric solution stains these boards, adding a yellowish tint. Is there any way to avoid this? Or clean it after?
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Ferric chloride staining PCB substrate
2017-07-03 by Brad