If I have populated boards that have gold plating/flashing that I want to recover from the boards themselves... from what I understand thus far as the best/proper process would be...
After cherrypicking certain components of interest (MLCCs of a certain size & larger, IC chips, SMB Tantalum Caps, IDE-type pins, etc.)...
1. Hot sand bath to remove the remaining soldered on components (or maybe heat gun and tapping?)
2. Then hot HCL soak to remove any remaining solder (I'm assuming in a sealable beaker or other heat-safe glassware and to me "hot" is a relatively loose term... not sure if just heated or boiling in some manner)
3. Then Lye bath to remove solder mask (for the boards with gold under the mask)
4. Then HCL + airbubbler ..or.. AP method to remove the gold plating/flashing foils (of in which I still have some questions about this method even with just the simple gold fingers recovery)
5. Filter, rinse and collect said foils until later for some sort of refining process and save whatever other possible particulates to later figure out what might be in it.
6. And secure & save the HCL for future depopulating only use until it is spent
Am I right in the steps above? Or am I missing something or too many steps?
Also... could I not just skip the hot sand bath and let the hot HCL soak remove the various components since that "eats" the solder that holds them on? Granted I would snip off any aluminum capacitors first (my scrap yard allows me to add those caps to my sheet aluminum scrap) since HCL reacts violently with aluminum and remove as much plastics as possible.
Like others on here... I'm not exactly looking for profitabilty vs time and whatnot per se right now. More of a just wanting to learn here in the beginning and is a hobby of a sorts. Profit considerations can come later on once better perfection of methods and eventual better understanding of various chemicals used... and of course more experience. For the moment, HCL (muriatic acid I should say... not lab grade) is the only chemical I feel comfortable enough to start using. And outside use at that.
After cherrypicking certain components of interest (MLCCs of a certain size & larger, IC chips, SMB Tantalum Caps, IDE-type pins, etc.)...
1. Hot sand bath to remove the remaining soldered on components (or maybe heat gun and tapping?)
2. Then hot HCL soak to remove any remaining solder (I'm assuming in a sealable beaker or other heat-safe glassware and to me "hot" is a relatively loose term... not sure if just heated or boiling in some manner)
3. Then Lye bath to remove solder mask (for the boards with gold under the mask)
4. Then HCL + airbubbler ..or.. AP method to remove the gold plating/flashing foils (of in which I still have some questions about this method even with just the simple gold fingers recovery)
5. Filter, rinse and collect said foils until later for some sort of refining process and save whatever other possible particulates to later figure out what might be in it.
6. And secure & save the HCL for future depopulating only use until it is spent
Am I right in the steps above? Or am I missing something or too many steps?
Also... could I not just skip the hot sand bath and let the hot HCL soak remove the various components since that "eats" the solder that holds them on? Granted I would snip off any aluminum capacitors first (my scrap yard allows me to add those caps to my sheet aluminum scrap) since HCL reacts violently with aluminum and remove as much plastics as possible.
Like others on here... I'm not exactly looking for profitabilty vs time and whatnot per se right now. More of a just wanting to learn here in the beginning and is a hobby of a sorts. Profit considerations can come later on once better perfection of methods and eventual better understanding of various chemicals used... and of course more experience. For the moment, HCL (muriatic acid I should say... not lab grade) is the only chemical I feel comfortable enough to start using. And outside use at that.