Is the white solder mask handled same as green?

[Metaphore]

I got a few of these white boards: https://www.dropbox.com/s/uvjhu3yub8b13ka/White solder mask pcb.jpg?dl=0

What's the best way to remove the white solder mask? Lye, same as a green mask?

I'd appreciate any suggestions on the best way to process these.

Thanks!

 

[g_axelsson]

I don't think there are any real differences between various colored solder masks. But you should check on a small sample that you have gold under the mask. Take a razor and scratch the surface.
In the picture the white solder mask looks like there are dark traces under the mask, if it was covered in gold I would have suspected a lighter shade.

Göran

 

[Metaphore]

I scraped the traces and they are definitely gold. That's a drop of 22kt testing solution on the trace. https://www.dropbox.com/s/r3wlvrgeayf77xb/White solder mask scrape.jpg?dl=0

 

[butcher]

I see some gold plated spots in the picture that was not under the white caoting. That scraped portion where you removed the solder mask looks like copper to me, it also looks like the acid dissolved some of the copper giving a blue reaction, maybe you just consumed the drop of acid in the drop of testing solution, before it could dissolve the whole trace of copper strip underneath it.

 

[Metaphore]

butcher, what is the "drop of acid in the drop of testing solution" are you referring to? I didn't use anything but a 22k testing solution. Maybe I need to learn how to use this stuff, I was under the impression that if it changes color, it's gold. Is that wrong?

 

[g_axelsson]

Let me sell you some gold! Special price just for you! 8)

Yes, you got it wrong. The testing solution is used with a "touch stone" and the way to use it is to make a streak with your unknown gold object and compare the speed it is dissolved with a reference streak of a known karat. The blue you see is copper nitrate.

Time to hit the books again, or at least the search function of the forum.

Göran

 

[rickbb]

Yep, you got it backwards, reaction = not gold, or at least less than the K value of that test solution.