Summary for stannate tin plating Discussion
cyanide copper and stannate tin process questions are raised by Seth S., who is documenting an in-house capacitor plating line and wants to verify whether the bath makeups and operating settings are reasonable. He describes a tin bath with caustic soda and sodium stannate, a copper bath with sodium hydroxide, copper cyanide, and sodium cyanide, plus a variable AC-to-DC power supply, filmed tin anodes, and vapor degreasing followed by DI rinsing. He asks for confirmation of the chemical mix and for recommended amps or volts, especially any ASF guidance. The only direct process guidance comes from Alex Sirota, who says his tin-plating practice uses NaOH at 1-2 oz/gal and sodium stannate at 4-7 oz/gal, with bath temperature at 160-180 °F and plating at 10-40 ASF. The thread does not fully validate the copper bath, so the discussion is only a partial sanity check rather than a complete process specification.
“Electroplating and Electroless plating of Copper and Its Alloys”
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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!
Seth S.
– Tucson, Arizona
October 21, 2024
This is a meeting place for camaraderie & sharing, not a free consultancy. So some readers don’t engage with anonymous posters.
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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