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need help to stop oxides on PCB

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rambo99

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I make my own PCB and I need to stop oxides is silver plating powder is ok for the pcb I have uses the lacquer I have clean the board and lacquer but after a day the board has oxides which is the best way to fix this problem.
 
for exaple you could laquer it with liquid flux i.e. kolophonium dissolved in isopropyl alcohol, just a small concetration of kolophonium in IPA like 20% should do.

Or some other solderable mask.
 
Last edited:
for those of us who speak english..... kolophonium=rosin
actually, coating with any reducing agent would work. i also am guessing the OP is in a damp climate. keeping your PCBs in a sealed container with a few silica gel packets might also help.
 
Gold plating is ideal -- and expensive. Tin plating is easy and more affordable. Normally, after cleaning all the flux from the solder-side of the PCB, I just shoot the back of the board with Krylon Clear Spray. It's a thin-enough coat that you can easily do board repair (use clear fingernail polish to recoat the repaired area) yet thick enough to stop oxidation. Unless the board is being used in a nasty environment, corrosion reduction just from exposure to air is more a cosmetic concern. Board with bare copper made in the 1960s still work fine today.
 
I can not have bare copper for most of my projects one is the homemade computer which the parts are 74AC and 74HC I try to fine the liquid tin in Australia the only can fine the liquid flux which is the best so far
 
I can not tell you any thing as I don't no my self all I no is I make the board I clean it and lacquer after a day or two I can not see copper two of my projects did not work because of oxides one off them is a home made computer when i replace the board it ok
 
I do this.
Etch the PCB and drill it.
Clean the PCB with soap water and a tooth brush.
Spray the PCB with a light coat of acrylic lacquer.
Solder the parts and test the board.
Spray the PCB with several heavier coats of acrylic lacquer.

You could use a conformal coating instead of the lacqur after soldering.

This does not work for SMD construction. For that I use liquid tin but do not care for it. I have tried other non plating tin/silver methods and they were worse. The spray is far cheaper and easier to use with good results.
 
I can not have bare copper for most of my projects...
Can you tell us why? I have several home-etched pcb´s with no coating at all and they still work even after 10+ years.
Do you have such environment that your copper gets green over a few months? I think if you use reasonably thick traces according to the method of pcb manufacturing, clean the boards wel after etching and solder parts soon after you made the board you should have no problems at all. Unless you live in the heart of a rainforest of course.
 
I can not tell you any thing as I don't no my self all I no is I make the board I clean it and lacquer after a day or two I can not see copper two of my projects did not work because of oxides one off them is a home made computer when i replace the board it ok

What are you etching with?
How are you removing the resist?
What are you cleaning with before applying the "lacquer?"
You say "lacquer." What does the label actually say? Are any ingredients given? Is it water or solvent based?

John
 
WHY can you not have bare copper for your projects? Does the inside of your house have a high concentraction of nitric acid or something?
 
gold plating is not only expensive, but gold contamination of solder makes it very brittle, the liquid tin idea looks good. my question would be whether it grows tin whiskers.
 
It is unclear why the coating is not working.

Rant on:

It is a bit irritating when people fail with a process that should work and go off seeking alternatives. It is far better to understand why it failed prior to moving on to another process. The same problem may well cause problems with the next process.
 
It is unclear why the coating is not working.

Rant on:

It is a bit irritating when people fail with a process that should work and go off seeking alternatives. It is far better to understand why it failed prior to moving on to another process. The same problem may well cause problems with the next process.

Couldn't agree more. See post #12.

Unfortunately, the OP has not replied at all.

John
 
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