Re: PCB through hole activation for copper plating
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Hi all,
the reason is drilled holes activation: the standard way to make conductive holes is to drill them on a blank board, then "activate" (get them to have some conductivity) the internal surface of the drilled holes, then do electroplating of copper to grow a sufficient layer of copper inside the holes.
If I remember correctly, there are other ways to activate holes. A long time ago, I experimented with it, with limited success. I tried to replicate this:
The best I could manage was to get 95% plating of the holes, which is not what you want. What I mean is: I did test boards while tuning the process, with a couple hundreds holes, trying to plate them, then measure each and every single one of them with a milli-ohm meter. And in every single batch, I had failed holes, either with zero connectivity, or too high of a resistance.
I gave up, but maybe someone could be more successful with it?
C.
what is the reason ... process....? to use Calcium Hypophosphite when
home brewing a PCB?
On 06/11/2020 01:29 PM, Jim Higgins wrote:
>
> Hypophosphites can be used in the manufacture of methamphetamine and
> some other controlled substances requiring similar reactions, so it's
> hard to get in the USA. No telling what you'll get from Asian vendors
> on Ebay, or if you risk seizure by customs. If you do order from them,
> you better specify DHL shipping or you might not have it before autumn.
>
> If the PCBs are only 2-sided, and you're willing to drill 0.062"
> holes, you might try brass eyelets available for this purpose from
> Mouser. The holes will be 0.045" when the eyelets are in place.
>
>
> Or solder copper wire in the holes... something I wouldn't want to do
> if there are many holes... but for a one of a kind home-made board
> that's the way I'd go if I could tolerate the required hole size.
>
> Jim H
>
>
>
> Received from Terry Gray at 6/10/2020 23:58 UTC:
>
>> Does anyone on the list have access to Calcium Hypophosphite?? This
>> stuff is impossible to find in the US, being a "controlled
>> substance".? For crying out loud. I really can't see the point
>> considering the volumes we are talking about!
>>
>> Alternatively, do any of you chemistry majors out there know of a
>> substitute formula using more easily available chemicals?
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