Has anyone tried electroplating over a soldermask?

Thread Starter

uknow

Joined Apr 2, 2012
9
Will this work instead of using immersion tin or will your whole board end up being electroplated? Anyone ever tried this? I would guess it would be completely electroplated but maybey not...
 

#12

Joined Nov 30, 2010
18,223
One definition of soldermask is, "stops liquids from contacting the copper".
Therefore, I disagree with you.
As long as the liquid you use to electroplate does not dissolve the soldermask, it would seem that you will only electroplate the bare metals.
 

Thread Starter

uknow

Joined Apr 2, 2012
9
I've never heard of pcb manufacturers doing this though...if it works well why don't they use it...or maybey they do?
 

mcgyvr

Joined Oct 15, 2009
5,394
Its done all the time.
Ni/Gold/Immersion Tin/HASL are the most common finishes.. All applied after the soldermask.
 
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Thread Starter

uknow

Joined Apr 2, 2012
9
But those aren't electroplated.

Don't the immersion techniques use the electroless process? The Tin HASL sounds interesting though so I could just dunk a pcb in a pot of melted tin and blow it off with an air knife or is the pure tin melting point too high? I know the solder and tin melting points are very close. I would like more control of my tin layer though...
 

mcgyvr

Joined Oct 15, 2009
5,394
Sorry should have clarified.. HASL and immersion tin are obviously not but NI/Gold/Tin are all electroplated onto a PCB as a final finish.. There are also electroless NI/Gold (ENIG) as well as using immersion silver now with ROHS/tight pitch components.
basically there are both electro and electroless processes that are commonly used depending on your needs.
 
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mcgyvr

Joined Oct 15, 2009
5,394
The Tin HASL sounds interesting though so I could just dunk a pcb in a pot of melted tin and blow it off with an air knife or is the pure tin melting point too high? I know the solder and tin melting points are very close. I would like more control of my tin layer though...
Huh?. many solders are tin.. Up until a few years ago (prior to ROHS) most places were using 63/37 solder (tin/lead).. Now ROHS has more or less banned lead but straight tin has other issues (tin whiskers) so other methods are now being used like immersion silver/OSP/ENIG.

IMO there is NO real point in applying a brush on or attempting HASL on DIY boards. Its just so the DIYers feel like they have a real circuit board.
 

Thread Starter

uknow

Joined Apr 2, 2012
9
Very nice I will be trying to electroplate over my soldermask then. Probably won't be for awhile but I'll update this post when I do.
 

Thread Starter

uknow

Joined Apr 2, 2012
9
Oops just noticed you said pure tin causes wiskers...is there any diy electroless nickel immersion gold or Organic solderability preservative...not necessarily diy but how do you make it?
 

mcgyvr

Joined Oct 15, 2009
5,394
I don't understand.. Did you DIY a circuit board and actually applied a real solder mask to it? or what.. spit it out man.. :)
 

WBahn

Joined Mar 31, 2012
26,398
Sorry should have clarified.. HASL and immersion tin are obviously not but NI/Gold/Tin are all electroplated onto a PCB as a final finish.. There are also electroless NI/Gold (ENIG) as well as using immersion silver now with ROHS/tight pitch components.
basically there are both electro and electroless processes that are commonly used depending on your needs.
How do you electroplate a board that has mostly electrically isolated tracks?
 

Thread Starter

uknow

Joined Apr 2, 2012
9
I don't know if it's considered a real soldermask but right now I'm about to try a uv cured soldermask that you get from ebay. It should look really professional : ) I havn't actually used it yet but I have everything to use it. Just stuck on the last issue of applying something for the pads so they don't oxidise. And in a professional way.
 
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