Lye In removing gold plate

[MrAndy]

I'm using lye to remove gold plate from copper base material, I bring it to a boil add Lye and in minutes it leaches all the gold off the material some times.
My question is as I'm doing this sometimes it just stops and well not take it off the same material from the same batch with the same bottle of lye everything
is the same but it just stops working, even when I start with another beaker it dose not take it off when I just took it off the same material? What am I doing wrong?

 

[niks neims]

why would Lye leach gold, how?

I think you have your chemistry mixed up...

hit the books man

 

[galenrog]

What is happening is the liquid sodium hydroxide, at elevated temperature, is reacting with copper, and its alloys. Gold is unaffected.

Why your reaction stops? I do not know, having not removed gold plating in this manner.

Still, your misuse of terms shows ignorance. This can be remedied with study coupled with small scale experiments. As Niks suggested, hit the books.

 

[Lino1406]

Maybe the "copper" contains zinc which is affected (brass)

 

[Yggdrasil]

I'm using lye to remove gold plate from copper base material, I bring it to a boil add Lye and in minutes it leaches all the gold off the material some times.
My question is as I'm doing this sometimes it just stops and well not take it off the same material from the same batch with the same bottle of lye everything
is the same but it just stops working, even when I start with another beaker it dose not take it off when I just took it off the same material? What am I doing wrong?

There have been a few answers here,
And some good advice.
I'm just curious where you found this idea?

And here is for your reading.

We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: Screen Readable Copy of Hoke's Book
2. Then read the safety section of the forum: Safety
3. And then read about "Dealing with waste" in the forum: Dealing with Waste

Suggested reading: The Library