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Re: copper plating - Electrode Tips
Original poster: "Brent Turner by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bturner-at-apc-dot-net>
Terry -
Yes, proper pH is critical to a successful plating job. Too much acidity
and you oxidize the surfaces and also the plating layer - hence that
spongy stuff. Not enough and the plating layer doesn't bond with the
material being plated.
That guy at work with the copper desktop is right -- one chemical used
in electroplating is urea. (Likely derived as uric acid from human pee.)
Also goes by the name thiurea (if I remember my spelling.) I use to do
my own tin-plating on copper printed circuits that I'd make in my
garage, and the system won't work without the urea. (Never tried peeing
into it though. *grin*)
Current density is also critical so as to form a slowly building layer.
I've heard that ordinary table sugar will help produce a hard, shiny
plating.
You might want to dig around some used book stores or a few engineering
college libraries to find books on electroplating.
- brent
Tesla list wrote:
>
> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>
> Hi Mike,
>
> For copper plating tungsten, for easy soldering....
>
> I found "ZEP Commercial Root Kill" at Home Depot. It is used to keep roots
> out of sewer lines. 99.0% Copper Sulfate Pentahydrate and 1% "other". I
> assume that is "the right stuff"... I could not find anything specific
> that was sulfuric acid... Mostly caustic lye type compounds...
>
> I dissolved "some" in water and added a section of 1/4 inch copper tube
> (anode (+)) and a tungsten rod (cathode (-)). Didn't work well at all.
> Just formed soft black spongy stuff (really cool though). More current
> more mess...
>
> I then found some Phosphoric Acid used as the common "PH Down" for
> adjusting the PH of aquarium water. With a very liberal squirt of the
> acid, the reaction changed completely to an obviously much better state.
> So the acid part seems very important. I tried a lot of current with a
> little bubbling and the soft layer of copper wipes off. I am trying a much
> lower current now... I can probably get sulfuric acid from the pharmacy.
> One of the local pharmacists looks like he personally tests everything
> before he sells it... he probably has the right attitude about ordering
> "anything" I need :-))
>
> A guy at work did a beautiful perfect shiny copper plating job a few months
> back on his desk. He was explaining it all to me but one of the main
> ingredients of the plating bath was human urine... and then I didn't want
> to know anymore :-p I'll go ask him more now that I know the true value of
> such information...
>
> I just checked the 1/2 inch long bit of 1/8 inch rod in the solution at
> 10mA. A "little" better but still rubs off... I think the solution
> contents are probably a bit critical... Needs more research on how one can
> make the bath with readily available chemicals. I do have a nice gram
> scale... Seems to need better chemicals....
>
> Chemystery was never my strong subject, but doing me best :-))
>
> I also got some stuff to try some silver brazing and all that. Wow!, you
> think I am bad at chemystery!! I solder extremely well. But welding... I
> can incinerate just about anything with a MIG welder and my fancy MAPP gas
> torch has a "ludicrous" heat setting... So I am all ready to go!!! :-D
> The guys at the welding shop have now learned to try and keep the crazy
> long haired guy in the suit on the premises while I am asking for a few
> boxes of acetylene and a few bags of liquid oxygen cause "I want to heat
> something up really bad"... While the guy in back frantically calls the
> BATF ;-))) Fortunately the day job gets a ton of $$$$ stuff from there so
> they are super nice no mater what... They usually give me fun dewars of
> LN2 nice and cheap just to get rid of me... When needed, asking for an
> MSDS sheet for leather welding gloves always works :-)))
>
> I have some pals that can do this stuff for me, but having too much fun
> myself :-)))
>
> Cheers,
>
> Terry
>
> >At 06:46 PM 8/12/2001 -0400, you wrote:
> > Yes, copper sulfate is a commonly used algicide. Although all the
> >plating baths I have ever used contained sulfuric acid, I don't know that it
> >is really necessary. I think it merely adds to the conductivity of the
> >solution and increases the efficiency. That probably doesn't really matter
> >if one is just plating a small piece or two.
> > Actually, if you want to take the time to do it, you can make a saturated
> >solution of copper sulfate and use a lead anode(+ electrode for anyone
> >unfamiliar with the term). You will deposit copper metal on the cathode,
> >release oxygen bubbles from the lead anode and generate sulfuric acid. The
> >hydrogen ions (from splitting water molecules) replace the copper ions
in the
> >solution. Once you have generated a bit of sulfuric acid, you can replace
> >the lead anode with a hunk of copper to continue plating forever with that
> >solution. You might want to add a bit more copper sulfate crystals if the
> >concentration get very low from the acid generation.
> >Mike
> >
> >