@Simao:
Could you please post the links regarding homebrew black hole formulas? I haven't found it using the search engine here or googling.
Regards
--- In Homebrew_PCBs@yahoogroups.com, Simao Cardoso <simaocardoso@...> wrote:
>
>
> Simon Gornall wrote:
> > The SSR's will arrive in January next year, so perhaps I'll have a
> > chance to work on it then.
> > Apart from the chemistry, you're still looking at the high-hundreds
> > for a reverse-pulse-plating machine if you DIY it. I can't see the
> > price being much more "affordable" than that if it's sold
> > commercially.
>
> Hi, Which SSR's are you using? Can they do 0.5ms pulses? Or operate at
> 1V or less? The turn on time and the minimum voltage to operate seems
> out off necessary range. Most the datasheets i shaw for 10-50A DC SSR's
> had 10ms maximum turn on time, and 3V minimum required voltage to
> operate. There was some at sub-0.5ms turn on but for 1A or so. Just
> wondering did you checked if the SSR's you ordered fit the purpose?
>
> Pulse plating documentation refers the value of a good square wave so
> fast turn on/off is recommended. Mine idea of a plating driver was
> started by a crazy wish of a electronically regenerated etchant, was to
> test chemistries than could fit this desire, were very high current
> densities define the efficiency. Fitting both purposes became not so
> simple.
> But any person with it's feet on the ground would just need 2 MOSFETs, 2
> PSUs, a dual driver and a MCU with PWM to archive it. STP80NF55 (one for
> direct other for reverse) and any dual 10V 2A driver gives you around
> 100ns for less money than one SSR.
>
>
>
> It helps me some brainstorm-loud-thinking to set some ideas from
> questions raised on this old thread, so...
>
> Trying to understand the copper plating required voltage: Half Cell
> potential for copper is +0.34V, if i understand the thing right, using
> both copper anode and cathode there is no minimum required potencial for
> deposition. According to graphics from cyclic voltametric stripping
> (CVS) tests used to mesure additive behavior/content, copper start
> plating right at 0.0V+, it start increasing faster at 0.2~0.3V and this
> curve can be slower according to additives use. The current increase up
> to a standing current point, that stands until the water electrolysis
> voltage.
> I don't really remember the precise value on the bath i had access to,
> was something about 2V in the power supply voltmeter. But wires,
> connections and resistive titanium holders will always increase this
> value on the power supply stage. Before i tried to get a simple answer
> to this so i could choose PSU voltage, and got ~0.7 minimum 3V best, and
> was wrong, i don't find any such reference in any documentation now, and
> a 5V PSU may only fit if enough resistance exists between PSU and
> plating cell , or by adding one power resistor in the circuit.
> Finding water electrolysis voltage value is not easy without having good
> chemistry skills, i think it's 1.23V, but in a sulfuric bath should be
> 2.05V but don't know for sure.
> According to real descriptions shared on this discussion group: One
> platter and is bought palladium chemistry and additives, say 0.6V for
> plating voltage. He describes for PSU a 5V toroidal transformer and a
> light dimmer on AC side for regulation. He later added series rectifier
> diodes on the DC side to increase the minimum voltage about 3V so the
> light dimmer work as useful controller. Other platter with is fully
> homebrew carbon black chemistry describes using a 5V output from an ATX
> PSU with steel wire as power resistor, using a alligator clip to choose
> desired current position. He reports 0.7V on the bath 1.6V at PSU with
> macdermind brightener.
> Seems to be possible to conclude that plating will occur under 1V and
> with total connections and wires resistance should be required 2~3V on
> the PSU. The use of one 5V PSU and a resistor can help the current
> control.
>
> ATX PSUs are a easy choice. I would also wish that adjustable voltage
> and current could be done for cheap at the PSU directly. I learned that
> some PSUs from meanwell use DC side simple PWM controllers, with a
> current sensor. On such, a resistor replacement by pots would be enough
> to slightly vary voltage/current. One attempt on a 5V 25A PSU didn't
> fully work, (but at least didn't ended in smoke like other times i tried
> to hack switched mode PSUs :D) IIRC i made the thing going down from 5V
> to 2.5V as expected but only goes back up to 3V... I couldn't test the
> current control because with a 20A multimeter directly connected, the
> PSU don't even power on, and trying with a steel welding rod as a 1ohm
> power resistor it didn't turn on either. I have to get something for
> test load, and the voltage modification isn't convenient done, at the
> store they didn't had the needed potentiometer values and i ended
> modifying other resistor values to fit. I have to try again.
>
> About the pcb plating, there are plenty people in this group which do it
> themselves (either by commercial/homebrew machines/chemistries), none of
> them, by what was shared, seem to bother with reverse pulses. It's an
> obvious good thing, but not an simpler/complete solution.
> Currents and pulse times vary with chemistries, and such vary with
> desired throwing power and aspect ratios. You can find very
> different&confusing copper/acid ratios between chemistries; high aspect
> ratio tend to have more acid and less copper; faster high current
> densities have more copper and less acid; reverse pulse chemistries
> prefer less acid more copper and highly suppressing current additives
> (bigger potencial variance for current adjust).
> Using additives can be PITA in medium term for a non chemistry knowledge
> guy, like i have experienced. Worst, if using this less often you end
> not having all the technical stuff present in your mind, ending in
> mistakes and boring repeated readings, like myself.
> I would like to replace leveler with reverse pulses and brightener with
> filtration for my use, but further reading tells me its not quit as
> first thought, if it works will be like lottery. There is a supplier
> that promotes additives free, reverse pulse plating chemistry, but their
> patents don't disclosure much... except it don't use brightener or lever
> but use catalyst and suppressor (which are not consumed like leveler and
> brightener and are considered initial setup).
>
> Catalyst and suppressor additives are simple chemicals that i got, other
> 3 organic compounds used as leveler can afterall be found as dye or pH
> indicator in pure chemical too, but its useless without brightener
> (Cl-PEG-SPS based system). Brightener is impossible to get as pure
> chemical in low quantities, only from plating supplies as a set. But for
> both leveler and brightener were once used thiourea (i also have it)
> with the downside of lowering plated copper conductivity.
> In the day i finally manage to get all the chemicals for the activation
> chemistry i most probably will use a very simple DC plating setup. Too
> much variables is a bad start.
>
> About the graphite drilling activation, i managed to find a old post
> from the same author of
> drilling-above-graphite-powder-mechanical-activation about his success
> rate, were he says better than 1:200 hole failure rate! (but with
> previous descriptions of 50% failure on <0.6mm holes and a initial
> success report of 10% failure rates with 1mm holes). So considering
> 0.8mm vias and a learning curve seems a fair good system.
>
> I also managed to find a number for the carbon black bath life. Graphite
> chemistry can reach one day life, it suffers from CO2 absorption. Carbon
> black as a problem of losing (???) oxygen, but i never saw bath life
> quantified. The person says that expect 1-2 years life with his homebrew
> chemistry. I was guessing much less, and am still curious about how the
> real life ended to be...
>
> About palladium and carbon black. The plating machine i had access to,
> had quiet some history about misuse of the chemistry. Loosing the
> palladium bath by drag-on from previous bath because insufficient
> rising, plated copper peeling off because not yet hot salt remover use,
> and so. Not only is a bit sensitive but one have to use it rigorously.
> And people tend to make mistakes with it, i was told that similar
> machines were without use because owners ended spending more money with
> it that if ordering the PCBs from a boardhouse.
> Besides the drying and repeat steps of a carbon black chemistry, if one
> could mix it from things possible to dump without worrying about money
> spent or environmental issues, if one damage it, it's always easy to
> start over.
>
> Good year,
> Simao
>