Homebrew PCBs

On Sun, 26 Feb 2012 09:32:25 -0500, you wrote:

>On Wed, Feb 15, 2012 at 4:11 PM, Harvey White <madyn@...> wrote:
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>> I was wondering if anyone had either of these pieces of equipment and
>> if they had any particular pointers. As I mentioned, the superfuser
>> seems to be able to do the job in 1 pass.
>>
>> Harvey
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>I had an older model of the tank. Don't know if there are any design
>changes on your model.

A lot, from what I can see.  

Minimal:  one heater rather than two.

Significant:  Entire box is made of transparent acrylic.  From what I
can see, the original one was made as an insert on a plastic (gray)
file box.  

Same:  Pumps, though.  You must have the pumps running to heat the
etchant.

>
>I think I used ammonium persulfate  (may have been sodium)  in the tank.
>Worked well, but does need a fair amount of enchant in the sump of the
>tank, also the enchant has a limited life span once it's dissolved in water.

Yep, so does Hydrogen Peroxide/Muriatic acid without adding more
oxygen.  I figured that one in.

>
> I had problems with the magnetic impellers on the pumps falling apart. Get
>spares.  Don't store enchant in the tank. Especially any enchant that tends
>to crystallize.

Ah, then I'll drain it out.  Thanks.

> Think it permeates the sintered magnetic material on the impellers and
>cracks them. (a lot of guesswork here).

Possibly.  I know that the peroxide etchant eats bubble stones, or at
least, the ferric chloride does.

Oh, and for experiments, there's a shock product for pools that is
about 4 something/lb, contains potassium monopersulfate.  Two bags of
that in a gallon of water will etch boards, about 9 dollars/load,
though.  Need to find a cheaper source of the pure stuff.

Note:  you want to make sure that there are no air bubbles on the
board.  I had a board where the holes in the pads did not etch
properly due to air bubbles.  

Thanks,

Harvey

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>-carl
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