This idea reminds me a whole lot of the method Edison
used in 1902 to produce molds to mass-produce cylinder
records. First they would take the master recording on
wax and then coat it with graphite and then put it into
a bell jar and pulled down a fairly decent vacuum.
The bell jar was equipped with a means to rotate the cylinder
and also with a way to connect it to one side of a high voltage
DC source. Nearby the rotating cylinder was a gold electrode
connected to the other side of the DC. After a long enough
time, the gold would plate onto the charged graphite surface
of the wax cylinder. Soon there would be enough gold
there to then continue the plating with copper to build up
a sturdy metal cylinder that had the exact groove impressions
as the master. The master was then melted out and then the
copper and gold mold would be pressed into a steel liner.
One of these molds could then be used to cast thousands of
hard wax molded records for sale to the public.
This is all very interesting indeed, because now that it's
starting to be understood that the vacuum is not really
a requirement if there is a hot spark with plasma, this could
open up some new possibilities for many related things.
Chuck Richards
http://www.richardslaboratories.com >
>
>---- Original Message ----
>From: stefan_trethan@...
>To: Homebrew_PCBs@yahoogroups.com
>Subject: Re: [Homebrew_PCBs] plating holes with an exploding wire
>Date: Thu, 6 Dec 2012 05:58:22 +0100
>
>>Nice idea.
>>
>>A similar method is used to gold plate samples for old electron
>microscopes.
>>
>>I've noticed a conductive metal deposit in plastic cases near the
>>point of (arcing) failure of the electronics inside.
>>
>>Usually this is called vacuum deposition, but apparently the vacuum
>is
>>not strictly necessary if the plasma from an arc is used.
>>
>>ST
>>
>>On Thu, Dec 6, 2012 at 4:54 AM, Jeff <jeff.heiss@...> wrote:
>>> A friend descried to me a method for plating through holes. The
>plating is accomplished by inserting a wire into the hole and
>applying a high voltage to the wire, exploding it and connecting the
>layers together. A pdf is available on google. It was too big for
>yahoo. Despite the questionable looking address, it is real.
>>>
>>> https://docs.google.com/open?id=0B9UJMWQidYN0ZE1yNWEzQmluSWc
>>>
>>> Curt's description
>>> It involves feeding a thin copper wire through the hole until it
>touches a massive ground plate which allows a capacitor charged to
>300 - 400 volts to discharge and literally melt the wire rapidly
>enough to cause it to 'explode' and bond to the internal copper
>layers. I find that 10 to 15 bursts leave enough copper for a sturdy
>through hole. I use an X Y table to position the board under a
>chuck that grips the wire and is connected to the high voltage
>source. A small stepper motor feeds the wire through the chuck from
>a spool.
>>>
>>>
>>> Jeff
>>>
>>>
>>>
>>> ------------------------------------
>>>
>>> Be sure to visit the group home and check for new Links, Files,
>and Photos:
>>> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>>>
>>>
>>>
>>
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