Thick plated pcb

[ItsaboutROI]

I have some thick plated PCB.. will the acid peroxide method still work on it? Does it matter if the plating is real thick like 100 microinches or more? Because I tried the acid peroxide method and I was unable to get the gold to be removed from the board the resistors and capacitors fell off but the gold is still on there. I didn't use a fish pump I just shook it occasionally maybe that's why It didn't work? I had tried hydrochloric acid and bleach on other boards and that seemed to remove the foil perfectly before I switch to that I'm wondering if anyone has any insight on why the acid peroxide method didn't work is it because I don't have the fish pump to continuously agitate the solution? I have attached a picture of the boards.. Thank you in advance for the help..

 

[Lino1406]

"Acid peroxide" with dilute H2O2 attacks base metals in priority after wounding the gold, what is difficult in the case of thick gold

 

[kernels]

Basically, AP doesn't work well on thick plated stuff because it can't get 'through' the Gold layer to dissolve the base metals below, so it can only attach said base metals from the small side area. For a smallish quantity of very thick plated boards, I would probably deplate with a Sulfuric cell.

 

[nickvc]

Another idea might be to score across the boards if you only have a few to allow the acid a chance to get at the base metals.

 

[anachronism]

I'd like to see the reverse side of the boards please.

 

[g_axelsson]

I'd like to see the reverse side of the boards please.

That is a good point, I would also want to know what the base material is? Fiber glass boards or some thick metal for thermal dissipation?

Göran

 

[ItsaboutROI]

I'd like to see the reverse side of the boards please.

Hey Guys thank you for taking the time to respond here is the opposite side of board... I have circled the parts that have fallen off and along with those there was some reddish sand looking material but gold was not really affected.

 

[anachronism]

Thanks.

Id be clipping off all the Tantalum capacitors before doing anything at all with these.

The Al caps are going to be dissolving in your HCl vigorously.

How many of these do you have? I ask because this type of gold plating is best dealt with using something like cyanide because it's fast simple and effective. I'd be finding a US member who is comfortable with the process and safety associated with it and sending them over.

The time you'll take do do these and the materials you will use will outweigh the toll fee.

If they were thick metal ones then weak Nitric should be tested to see if it works too.

 

[ItsaboutROI]

Thanks.

Id be clipping off all the Tantalum capacitors before doing anything at all with these.

The Al caps are going to be dissolving in your HCl vigorously.

How many of these do you have? I ask because this type of gold plating is best dealt with using something like cyanide because it's fast simple and effective. I'd be finding a US member who is comfortable with the process and safety associated with it and sending them over.

The time you'll take do do these and the materials you will use will outweigh the toll fee.

If they were thick metal ones then weak Nitric should be tested to see if it works too.

I have 40 of them.. Send them right over.. lol. Cyanide is too dangerous for me. Hcl bleach works just fine for thick plating.. I have attached a photo of other batches.Usually I get boards that have not had any chips, capacitors, etc attached to them.. I just thought that AP Method would work better on these since these had chips, capacitors, etc on one side.. I am sure i likely got the AP recipe wrong.. I should have used a fish pump too. But the one side all plated thick likely wont budge without something a little stronger..

 

[etack]

I had some boards for radar detectors for cars that looked like those. the gold was "THICK" on them too the thing was they had a varnish on them that made them feel thick.

Eric

 

[ItsaboutROI]

I had some boards for radar detectors for cars that looked like those. the gold was "THICK" on them too the thing was they had a varnish on them that made them feel thick.

Eric

So the boards you had turned out not to be really thick plating and it was just the varnish? I was assuming mine were thick because the Acid peroxide did not do anything to them..