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Cyanide Copper & Stannate Tin Process Questions

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!

Seth S.
- Tucson, Arizona
October 21, 2024

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