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Pine Beach, NJ
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Cyanide Copper & Stannate Tin Process Questions
by N. Kanani
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Q. We are a capacitor company that has a copper and tin plating solution in-house. I am working to update some of our work instruction literature to assist new employees on how to operate the equipment properly. Currently its a lot of "tribal knowledge" from the person who set it up 10+ years ago. I would like some clarity on proper plating techniques so i can record them for future colleges. I would like to run by the basics of what i have recorded for a sanity check that the baseline process is sound.
Now onto our current process. Tin bath is a 60 gal tank with 7 lbs of Caustic Soda and 48 lbs of Sodium Stannate. The Copper bath is 45 gal tank with 5 lbs Sodium Hydroxide, 8 lbs Copper Cyanide, and 12 lbs Sodium Cyanide. Does this sound like an appropriate mix of chemicals for this type of plating?
We utilize a variable AC to DC transformer that can output 0-9 VDC and up to 100 A. We film the tin anodes prior to plating parts. The parts are put through a vapor de-greaser and rinsed off with DI water prior to going into either bath.
We have voltage and amp readouts but I do not have a real figure to go off of for the "correct" amps or voltage. From what I understand there is a recommended ASF for tin and copper plating. Would someone have that figure handy?
Appreciate any help with my above questions. If I left something out that you need for reference let me know please!
- Tucson, Arizona
October 21, 2024
Ed. note: Many readers use their real names because they enjoy the camaraderie of being part of this community; they may be less likely to engage with those who won't.
A. We perform tin plating. Solution: NaOH 1-2 oz/gal, sodium stannate 4-7 oz/gal, temp. 160-180 °F. Plate at 10-40 ASF. Good luck.
Alex Sirota- Lod, Israel
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