Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

On Sat, 2009-06-13 at 16:40 +0200, nisma@... wrote:

I think is PTH and not THP :)

> I have experimented with pyrrol based THP. I´m not shure, but if
> i remember correclty, the source speakes about a plastic
> polymerisation process with some activator, but i could remember
> wrong.

Great, so any of the chemistries pyrrol based I read about have
permanganate based desmear/etchback. Is potassium permanganate solution
stable over time?
It should be the pink bath first or second tank. For home use i want non
hazard stable solutions, permanganate seems beter in plenty of reasons
than ethanolamine/polyethyleneglycol based desmear, but i don't know if
is stable. Ok it needs 90ºC so water has to be added. But can i think
using it over time just adding fresh solution, or i have to be always
reading the pH?

Ethanolamine of bungard bath nr 1 is anesthetic, if not used in a closed
ventilated container you will start to talk funny, your mouth/tongue
wont move right from breathing it. And the mixture with PEG is said to
degrade at 70ºC, but should be used at 60ºC, so you have to heat it
slowly with a low power heater. The bungard machine takes more than 3
hours to heat the first bath, its boring. Using a more powerfull heater
will create temperatures above 60º close to the heater. With
permanganate i don't have hazard or fast heating problems. And potassium
permanganate is cheap and widely available.

Pyrrol in theory is a great hole activator, is a water soluble
conductive polymer, at least 'DMS-2' and 'Compact CP' chemistries use
it, but it polymerizes on the all board not only on holes when dipped in
the acid bath, so it needs a microetch after or is used similar thing to
pyrrol like thiophene (DMS-E chemistry), or furane (i think) (Compact CP
chemistry). If you find any common source for these things please tell
me!


> The average results was 800 Ohm of conductivity, but always under
> 1kohm

I tested what i think is a solid piece of PVP and i got 30Kohm, it
should be different in the acid bath or after it bond to de MnO2. With a
low current plating it may work, i should try it. It will be a simple,
non hazard, widely available solution, that can be drain without
problems.

>
> I want use the bungard chemistry.

Is a simple and safe option. But i don't want it at home. And they don't
sell it in less than 10liters kit. For about 1000eur. And i have much
against bungard, if i buy it will be from megauk, they sell exactly the
same thing from the same manufactor at lower price. Bungard just rips
the manufactor name from the label and resells it.

As i said is bath 1 Ethanolamine+PEG; bath 2 NaCL+HCl; bath 3 Pd+PVP
+HCL; bath 3 K2CO3; bath 5 acid copper plating.
If they sold only the bath 1 and 3 will be easy. You can buy
ethanolamine from dry film stripper. But any epoxy glue remover
(Methylene Chloride toxic) should also do. The NaCl use from dish washer
machine salt not table salt. And the palladium based activator search
for palladium nanoparticles or colloids. It can be used the simple to
mix PdCl2 SnCl2 but is unstable, every 20 hours use needs more SnCl. The
Pd/PVP is very stable. But is good thing to buy, seems made like this:

http://linkinghub.elsevier.com/retrieve/pii/S0021979705010350
http://pubs.acs.org/doi/abs/10.1021/jp0535801
http://www.rsc.org/Publishing/Journals/JM/article.asp?doi=b108260b



> Solar furnace or evaporation could be a good possibility.

Better is using only environmental friendly things like potassium
permanganate and polyvinylpyrrolidone!

> Don´t use refrigerator compresser, use instead a double stage ventury
> aspirator, (water outlet type) 5€. If you want go with the compressor,
> you need two stages.
>
> sorry for the short answer.

I will love to know what you have wrote, if in any other time you wish
to share i accept it even in german.

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