# kovar question



## kronix (Mar 9, 2012)

What happens if you use processors that contain kovar in AP? are you supposed to boil them in HCL instead? thanks.


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## lazersteve (Mar 9, 2012)

Kovar contains a high percentage of iron that fouls the AP preventing it from regenerating and being reused. 

Kovar is best processed in the stripping cell or dilute sulfuric acid to recovery the gold foils. Dilute 35% nitric acid will also work.

Steve


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## kronix (Mar 9, 2012)

if im not worried about re-using the solution because its a small amount will it still work? the only sulfuric acid i can find around here is called liquid lightning drain opener, im pretty sure its concentrated, it says "virgin sulfuric acid". what percentage should i dilute it to? also i can't get ahold of nitric acid where i live, im on an island with no chemical supply. i saw a video about cpu pins and he boiled the pins in HCL for 3 hours has anyone tried that method with good results? thanks.


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## samuel-a (Mar 9, 2012)

kronix 

HCl (31%), sulfuric acid (30-40%) and nitric acid (35%) will work at about the same rate while cold. All of them will work rather slow (days) on the cold, AP will be a little faster.
Hot dilute sulfuric will also work very fast and maybe even faster then HCl. Hot AP runs the risk of dissolving some gold and cementing it back as black powder but also work fast.

While the stripping cell has its merit, trying to strip such tiny pins you talk about (those that removed from CPU's) may prove challenging...

Just a safety note, If you ever try to dilute sulfuric acid, always add the acid to the water and do so very slowly.


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## Sucho (Mar 9, 2012)

For kovar made transistors i use diluted nitric acid with 30 g / dm3 of copper nitrate.it works at lab temp-it heats itself to quite high temperature.
I use this technique only for partially plated kovar.


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## auction_junkie89 (May 10, 2013)

While using Sulfuric Acid, about how much do you guys think would be needed to dissolve, say, 250g of CPU pins?


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## solar_plasma (May 10, 2013)

> For kovar made transistors i use diluted nitric acid with 30 g / dm3 of copper nitrate.it works at lab temp-it heats itself to quite high temperature.
> I use this technique only for partially plated kovar.



How long would this take for transistors? Are you cutting the cap off? How much acid is needed? Are using 2M or 4M HNO3 (to me both are "diluted")?


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