I was almost out of the ENIG gold-plated FR4 that I dremel for proto circuits, so we had Cirexx make us some more. This is 1/2 oz copper, which dremels nicely.
Certainly better than tin plate. Has anyone tried to etch gold plated boards with ferric chloride?
Cheers
Not much dissolves gold.
It solders beautifully and stays shiny forever.
Hmmm, I thought it dissolves very readily in solder.
Probably need aqua regia. Ferric chloride is miserable to work with but it makes aqua regia look like soda pop.
Gold is fairly inert, but Mercury will dissolve it. the nickel can probably then be plated off leaving the copper which can them be etched chemically.
Seems kind of messy.
, so we had Cirexx make us some more. This is
end with doubts, but if he will be content to
Different stroke for different folks I was going to suggest same kind of thing, a cheap clear coat like clear spray "paint". Good to know the idea has Phil's endorsement ;-)
I'm not in you guy's bizness but I remember long ago a former co worker (who once ran elec assy lines at GE, Schenectady, NY) mention something called "Stay Bright" -- when ordering bare non-plated etched PCBs. Searching for that now turns up other unrelated things. But I suppose PCB makers can offer clean meltable coatings, yes? = RS
There is some liquid that you can dip copperclad into that plates it with tin. It's not any better than bare copper.
If you do need to dissolve a thin layer of gold without using really nasty reagents, then an iodine solution is quite effective.
John
Am 06.05.22 um 19:56 schrieb Rich S:
I use solder laquer SK10 by Kontakt Chemie. It is an excellent flux and protects the copper but is not very hard against mechanical abuse.
When I want to test my circuit today, I use these Bungard presensitized boards:
<For microwave filters, where it counts, the print shop in the next village makes me an offset film from my PDF with true 2400 dpi.
For the flight hardware of space projects we had to remove the gold from the transistor legs etc. Looks good, but the Au makes the solder joints brittle. Non-compliance ==> junk pile. There was a tin bath just for this purpose.
A friend told me his grief when he tried to repair a YIG oscillator. Tried to solder a golden bond wire under the microscope. The gold wire disappeared as fast in the tin as he moved the tin blob. Shocking. It went simply into solution.
Cheers, Gerhard
Yup, been there. 2% silver solder is a big help in preserving the gold. Indium-tin eutectic also works well, but it's so low-melting that flux doesn't work well.
Cheers
Phil Hobbs
The gold on my boards is microinches thick. I'm sure that it dissolves in solder. But then the solder sticks to the nickel somehow.
The gold plated FR4 solders agressively. I have to be careful about little solder splashes ruining the prettiness.
Am 06.05.22 um 20:54 schrieb John Larkin:
This one is good and much better than copper:
<The Cu surface must be _absolutely_ clean. They have a special eraser rubber for it, quite abrasive. "Poliblock"
For me. it works best to put the etched Bungard presensitized board without photo mask under UV again and then use the NaOH developper to remove the photo resist.
cheers, Gerhard
But I don't want to dissolve it.
One board house wanted $1200 a square foot. Cirexx did 3 sq feet for $500.
Yeah, I recall that stuff; it just rubs on, and by electroless plating puts a bit of silver on a copper surface. Don't see any suppliers, but this shows up on a web search
So how do you remove fingerprints? Isoprop, acetone, soap and water?
(need to plan my next crime:)
Guess you never had the chance to see the Jim Williams workbench exhibit at CHM. Bummer.
The electrons don't care about aesthetics and the photons will get over it. The customers might, but you don't want those sorts of customers anyway.
-- john, KE5fx
On a sunny day (Sat, 07 May 2022 17:27:48 -0400) it happened Joe Gwinn snipped-for-privacy@comcast.net wrote in snipped-for-privacy@4ax.com:
Its a good investment....
On a sunny day (Sat, 07 May 2022 17:27:48 -0400) it happened Joe Gwinn snipped-for-privacy@comcast.net wrote in snipped-for-privacy@4ax.com:
Its a good investment....
I usually clean the bare board with soap and water, or occasionally some Barkeeper's Friend or 0000 steel wool with soap.
Once the board is dry, you hit it with the Krylon, then just do the dead-bug thing (using SMT breakouts when needed) as usual. It solders like a bare board.
Cheers
Phil Hobbs
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