At 04:11 AM 6/03/2002 -0000, you wrote:
>--- In Homebrew_PCBs@y..., Adam Seychell <adam_seychell@y...> wrote:
>> The cost is not the problem since the carbon dispersion should be
>available
>> free from one of the large colorant producers. The dye is similarly
>> available. I got 20 kg of dispersion paste for $130 AU. This is
>enough to
>> make about 1000 liters of solution. I've used about 100 grams so
>far. The
>> cost will be in building or setting up your chemical tanks. Plating
>copper is
>> easy but trying to plate uniform smooth copper on to your PCB takes
>a lot
>> more effort. I would say the carbon black process is simple
>relative to
>> copper plating. In other words, if you can get successful copper
>plating then
>> I'm sure the carbon black process will be easy for you. The success
>rate for
>> plating holes is just about perfect, but it has taken me a long
>time to get
>> at this stage. The guide I described is a good start. The only
>concern I have
>> is that a different carbon black dispersion concentrate may give
>different
>> results.
>>
>>
>> Adam
>>
>
>I had a nice long reply to the group, (covering two posts). But it
>seems yahoo decided to screw up my message. But the gist was
>the cost of producing prototypes at home or sending away. I am not
>too concern at plating since I am thinking of buying a prototype
>plating machine. I more worried about making the holes conductive.
>Your prodeduce looks appealing.
>
>Lates.
>
>
First you should worry about how your going to etch. If you decide on
pattern plate then you have choice of tin or tin/lead metal resist. If you
choose tin then you must use alkaline ammonia etch. If you choose tin/lead
then can use sulfuric/peroxide, ammonium persulfate etch, or ammonia etch.
However, I would be wary on having toxic lead plating solutions laying
around. For the ammonia etch it can be chloride or sulfate based. If
chloride based then you have major waste problems because the copper cannot
be recovered easily (at least what I know) and you will need to treat then
dump your solution ($$$). If you use sulfate based alkaline ammonia then
the etchant can be electrolytically regenerated although the etching rate
is much slower than chloride.
PCB fabrication may look simple on a flow chart but when it comes to
actually making it work its a whole different story.
Adam