video and sound card ?

[donald236]

hi guys
Ive got a question . i know that some of you guys that has been in this for a while has probably run in to this type of problem . first of all my eyes are not what they used to be . i guess that is a sure sign you are getting old . but anyway the video and sound cards have real small round dots and some of these go through the whole board and some dont . these dots that i'm refering to are not the silver dots . those are just test spots for the circuit board . the dots that im refering to is the ones that look like gold . are these gold or is that just the masking :?: now i know the base metal is copper but on some of these cards the base is gold under the masking . so what do you guys think :?: :?: :?:
thanks in advance
donald

 

[lazersteve]

Don,

Lots of cards, memory sticks, motherboards, and other pcbs have gold plating over the copper cladding on the board. sometimes this plating is localized to the exposed areas of the solder mask, while other times the gold plating extends under the solder mask. You should always check fro hidden plating by scratching away a small area of the mask to see if the gold plating is underneath.

Steve

 

[donald236]

OK thanks Steve . next question is can this gold be removed with out having to take the masking off :?: now keep in mind that I've done the scratch test and its copper based (under the masking). i feel like if a man was to remove the masking and it being copper based that the AP-bath would absorb more copper then it would not have any thing to work with as far as to get to the gold or would it :?: please correct me if I'm wrong .
thanks again
Donald

 

[lazersteve]

Don,

The amount of gold you will get is minimal compared to the effort you will put into it. You may want to trim out the sections of the card that has the gold plating and add it into a batch of fingers. Metal cutters or the scroll/band saw work great for trimming sections of cards down to size.

Steve

 

[donald236]

hey thanks steve just like always you are a great help .
thanks a million
donald

 

[pilotdan]

I'm starting to wash my boards with Sodium Hydroxide and table salt to remove the mask. I will let you know how well it works.

 

[g_opolis]

Hi all, my name is Robert. I've been lurking for a while, and am very impressed with not only the volumes of information, but the QUALITY of this info is unsurpassed. I tried the sodium hydroxide and salt on a batch of boards a couple days ago. It worked well on some ( completely removing the mask with a little scrub), but seemed to not even touch others. I did end up with many cards that were completely gold covered.

 

[wop1969]

can someon post a link to the recipe and steps for stripping the masks using salt and sodium hydroxide?
I have a tone of old pc cards and I am sure some are gold clad all the way

Or just post in here, Thanks