getting rid of gold on pcb

[ChairmanOfTheBored]

Gold is one of the least reactive metals. The classic reactant is aqua
regia. I doubt that a bit of chlorine in water would have much effect.
And anything that eats through gold will go wild when it hits the
copper.

Gold is only second to Platinum where oxidation effects come in.

Both could stand a hundred years at ambient and not tarnish one iota.

They are more than a little immune to chemical attack as well.

Soldering involves heat. Dissolution of these metals during soldering
would not occur were it not for the heat involved. This is why one
should always solder with as low a temp process as can possibly be
tolerated while still achieving proper wetting, and good
micro-crystalline solder joint structure. High heat increases
intermetallic contamination in ALL cases.

 

[[email protected]]

<snip>

Threaten to not pay or cancel payment untill they fix the problem.

If it's their mistake they should correct it.

al

 

[Tim Williams]

Superior products that can do more than one hair, one eye or one ear..

"Damnit, where'd I put my other pant!"

Tim

 

[Michael A. Terrell]

Brasso has been available in the US for at least 50 years...and is
still available.

1905

http://en.wikipedia.org/wiki/Brasso Apparently, it's one of the few
good things we got from England.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[John Larkin]

1905

http://en.wikipedia.org/wiki/Brasso Apparently, it's one of the few
good things we got from England.

British Common Law.

Cheddar.

The magnetron.

Telequipment oscilloscopes. Just kidding!

There must be a couple more.

John

 

[Martin Griffith]

British Common Law.

Cheddar.

The magnetron.

Telequipment oscilloscopes. Just kidding!

There must be a couple more.

John

Windward Islands, marmite, trains, antibiotics, Thatcherism, Habeus
Corpus, 3 weeks paid annual vacations, punk, Jet engine, Bombe,


Martin

 

[JosephKK]

TT_Man [email protected] posted to sci.electronics.design:

I would have thought the same..... going through HASL should remove
the gold. Maybe you need to do it a couple of times..... not sure
what the fab plant will say about having their solder contaminated
with gold though. But doesn't the molten gold float on top of the
solder?

If it did not dissolve or go into suspension it could precipitate (to
the bottom, after all, it is denser than lead).

 

[JosephKK]

D from BC [email protected] posted to sci.electronics.design:

I have no experience in this area so I'll just rattle off the wacky
ideas:

1) Sandblasting (copper microspheres?)
2) Planar (as with lumbar)
3) Wet abrasive and lapping (mirror polishing)
4) Air blasting at 1063C (Au melting point)
(Cu melts at 1083C and Ni at 1455C..but PCB will burn)
5) EDM engraving
6) 3:1 HCL:HNO3 etching
7) Chlorine gas etching or Chlorine in solution


D from BC

Personally i think the choices are:
Abrasives, ala pink pearl erasers,
Lapping should be controllable enough,
Plasma etching.

 

[JosephKK]

Martin Griffith mart_in_medina@ya___.es posted to
sci.electronics.design:

What else would aqua regia disolve? BTW in WW2 one nobel prize
winner dissolved his medal in AR to stop the nazis getting it. The
gold was recovered after the war are re-cast into the medal, neat.


Martin

Most certainly any local metal.

 

[JosephKK]

Robert Baer [email protected] posted to sci.electronics.design:

Brasso has been available in the US for at least 50 years...and
is
still available.

Most metal polishes contain reducing agents to convert the corrosion
back to metal. Kinda defeats the purpose to expect it to remove
metal.

 

[ChairmanOfTheBored]

British Common Law.

Cheddar.

The magnetron.

Telequipment oscilloscopes. Just kidding!

There must be a couple more.

The Beatles.

Pink Floyd

Alan Parsons Project

Genesis

Peter Gabriel

Kate Bush

The Who

A few more.

 

[John Larkin]

The Beatles.

Pink Floyd

Alan Parsons Project

Genesis

Peter Gabriel

Kate Bush

The Who

A few more.

William Shakespeare

Jane Austen

George Eliot/Mary Ann Cross

Anthony Trollope

E. M. Forster

P. G. Wodehouse

Dorothy Sayers

Patrick O'Brian

J. K. Rowling

Peter Hitchens

Mr Bean. Just kidding!

John

 

[Tim Williams]

(etc.)

Mr Bean. Just kidding!

(...)

Bessemer, of course.

Tim