depopulating cell phone boards

[ahmadbayoumi]

Thanks a lot steyr223 for your reply.

So I think Sodium Hydroxide should be my 1st step to remove the solder mask ..

Now for the Nitric, I think and after what you have mentioned wouldn't be an option because Incineration is also not an option due to the nature of the PCBs (large size).

So now I'm waiting for Geo or anyone that could help me on this.

Thanks again steyr223 and for everyone here in this great forum

 

[steyr223]

Also there are members here that will tell you they have seen gold dissolved in sodium hydroxide

Let see if i know geo he will tell you to scratch the board up so the ap can attack. Under the mask

Steyr223 rob

 

[Geo]

in my experience, cell phone boards are not gold plated under the solder mask. there must be exceptions but not any that i can find. no need to remove the solder mask before AP treatment. the AP, if done correctly by adding an air supply, will work its way under the solder mask as easily as it does the gold plating. if by chance you have a phone board that has gold plating under the solder mask, the AP will lift it off with no problem even under the solder mask. the solder mask will wind up as green flakes mixed in with the gold flakes but will not effect the dissolution of the gold by hcl/CL when that time comes. the green flakes will be filtered out after the gold is dissolved.

 

[ahmadbayoumi]

Thanks a lot Geo .. great information.

But if it's so for cellphone broads .. what about other breads ?

I mean which broads that would be gold plated ?

 

[Geo]

it will work the same for any modern (the past decade) board. i have had the (dis)pleasure of working with some old military boards that had gold traces under solder mask that AP would not effect. these boards had some sort of solder mask that even warm sodium hydroxide solution wouldnt dissolve. i had to physically cut around the edges with a blade so the AP could work underneath the solder mask.