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Hockeydemon
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Copper electroplating non-conductive material with PC power supply?
Just finished up a unit on electrochemistry in school, and I was reading around about electroplating. The other day I happened to find a lady friend
that tickles my fancy. Put two and two together, and we have ourselves a project hahaha.
The chick has a bunch of sand dollars, and seashells. I'd like to electroplate a few with copper.
That being said I'm starting from scratch on everything.
Power Supply:
I'm certain I have an old PC somewhere at my parent's house I can snag on my way home from work tomorrow. I might also have a trickle charger for a
car batter (plugs straight into 120V outlet). If this is preferable let me know, and I'll look for it.
Moving forward with the PC for the power supply unit. Which voltage wire would I want for the electroplating 5v 12v...? I was thinking about picking
up a little project box from radioshack and running it all through there so it is neat & tidy.
Lacquer
I know I need to seal these in a lacquer. What kind of sealant should I use? Just some generic clear polyurethane lacquer? Could I just dip the
material into a can of it, let it dry, and do this a few times? Or do I need to go through the trouble of gently hand applying it?
conductive paint
What should I use as the conductive paint to apply to the lacquer layer? Would a graphite paint use for PCB etching work? Or should I go about buying
some silver paint from somewhere?
plating
When plating copper to the materials how should I go about it? Should I use a copper sulfate solution along with dilute sulfuric acid as my solution?
For the anode can I just use random copper wire or piping from homedepot?
Then I just hook everything up flip the on switch and wait?
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Hockeydemon
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It just occurred to me that my roommate just acquired a couple arc welders, and a couple plasma cutters. I have no idea if they are AC or DC I'll have
to go find out, but how hard would it be to set that up for electroplating?
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DrSchnufflez
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For the electroplating you should use acidified copper sulfate solution with some thiourea added as a leveling agent - without it you would probably
end up with a dendritic copper sponge.
Good luck 
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Finnnicus
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I don't know much of this, but woelen's tutorial for ATX Units is here.
Oh, and test the arcwelders, find out what they pull.
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Hockeydemon
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The power source is no longer a problem. I completely forgot my parents have a large car charger - I grabbed it this morning. It can do 12A, 40A, and
100A charges. There are some other features on it I'll post when I bother looking at the thing.
So now the question is moved towards what kind of solution, and what can the anode be? I don't know the equation either - doesn't the surface area of
the anode & cathode factor in relative to the amps?
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papaya
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Anode must be made of copper (it'll dissolve and be transferred to the cathode),exact composition of electrolyte must be taken from some
guide/specialized book, but it is expected to be CuSO4+H2O+H2SO4+some C2H5OH in certain concentrations, current density is an important factor (A/cm2)
and voltage must be taken the minimum possible (less heating), fine tuning parameters during experiments.. (NO never did it seriously)
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Hockeydemon
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I have a large car battery charger that runs 12v/10amp,40amp & 100amp charges (It is possible the 10amp runs at 6v but I need to check). The total
surface area of the sand dollar is ~14-20sq".
I was going to seal the sand dollar in Rust-Oleum Specialty 11 oz. Specialty Lacquer Spray Paint from home depot. It is highly resistant to acid, and should provide a nice protective
coat (suggestions?). I was going to make the sand dollar conductive by picking up some PCB (circuit board) graphite paint (or silver?) from
radioshack. I was going to comprise my electrolyte solution using this stoichiometric ratio: 1.25 CuSO4ยท 5 H2O + .467 H2SO4 (Source of stoichiometry) - diluted with DI water to 1L. I was going to use copper piping for the anode - would you suggest a bath in sulfuric
acid in order to clean up possible impurities? I was going to use stump removed for my source of copper(II) sulfate - should I make an attempt to
purify this before hand or would using a 'dummy cathode' initially suffice?
Assuming all of that sounds reasonable.. I need to figure out how many/what kind of bulb system I should have - if one is even needed. Suggestions would be much appreciated.
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DrSchnufflez
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You could even seal the dollar then plate it with a chemically deposited amount of silver. Nurdrage has a video on this. I can't remember the name of
the reaction but it chemically deposits a fine layer of silver onto anything immersed in it.
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phlogiston
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I think all of the power supplies you describe are overkill. For such small objects, you'll need a few amps at most. Make sure to find out what the
current density should be (amps/sq inch).
You should include a means to adjust the current in your setup to match the desired current density. The power supplies you describe are probably not
very adjustable. One way to solve this is to vary the distance between your anode and cathode. More distance=more resistance=lower current. Because
these items are not very flat, you will want to make sure they are not very close together though, since you would then get faster plating at the
points of your object that are nearer the anode.
[Edited on 10-6-2013 by phlogiston]
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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
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Hockeydemon
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Quote: Originally posted by phlogiston  | I think all of the power supplies you describe are overkill. For such small objects, you'll need a few amps at most. Make sure to find out what the
current density should be (amps/sq inch).
You should include a means to adjust the current in your setup to match the desired current density. The power supplies you describe are probably not
very adjustable. One way to solve this is to vary the distance between your anode and cathode. More distance=more resistance=lower current. Because
these items are not very flat, you will want to make sure they are not very close together though, since you would then get faster plating at the
points of your object that are nearer the anode.
[Edited on 10-6-2013 by phlogiston] |
I'm able to construct a pseudo-rectifier using light bulbs. I run the positive line through a board of light bulbs which are X watt & X volt which
allows me to regulate what goes into the electrolyte solution. Or at least that was the impression I got when I read about it? I linked to it above -
if I'm mistaken please let me know.
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violet sin
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why not try mixing in some graphite powder(door lock lubricant) in the sealant, for an all in one coating? you would have to make sure it was really
fine or make it so your self. won't necessarily be good with just one coat but you get the idea, less chance of a thin or uneven conductive layer.
the thinner you apply it the more detail you retain. that is if you don't have the ability to flash a thin coat on to start. good luck
-Violet Sin-
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Hockeydemon
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| Quote: Originally posted by DrSchnufflez | | You could even seal the dollar then plate it with a chemically deposited amount of silver. Nurdrage has a video on this. I can't remember the name of
the reaction but it chemically deposits a fine layer of silver onto anything immersed in it. |
This is interesting to me, but as a separate experiment. It would be pretty cool to deposit a bunch of silver onto some things. I wouldn't want to
waste the silver by covering it up with copper though.
Can someone explain what is happening when you do this? It's similar to Tollen's reagent, but I'm not sure what is happening, or why there is sugar?
AgNO3 + NaOH + NH3 +C12H22O11 + heat?
What is causing the Ag+ ions to deposit on things? I am fearful that the lacquer will not stand up to the sodium hydroxide - though I only base this
on the fact that it is an acid resistant lacquer & not caustic.
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DrSchnufflez
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You first have to precipitate the
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DrSchnufflez
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Sorry accidentally hit send instead of the keyboard (I'm on a tablet)
So you need to precipitate the AgNO3 with some base to produce Ag2O which is then dissolved in ammonia to form a complex. This
complex is then reduced to silver which deposits out on to surfaces in the solution.
This procedure is all well and good but it deposits a brown layer of silver which is only mirror like when it is viewed through the object. For
example if you plate some glass then the side with the plating will be light brown and when viewed from the other side it will be mirror like.
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violet sin
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Acid copper plating and additive composition therefor
http://www.google.com/patents/US4038161
'''17. An acid copper plating bath for producing level and bright copper coatings comprising per liter of bath, from about
a. 165 to about 250 grams of copper sulfate,
b. 45 to about 75 grams of sulfuric acid,
c. 0.03 to about 0.1 gram of chloride ions,
d. 0.001 to about 0.5 gram of a water-soluble leveling agent obtained by reacting epichlorohydrin with a substituted pyridine having the general
formula ##STR13## wherein R is a lower alkyl, lower alkenyl, alkylene amine, mercapto, cyano, alkylene-4-pyridyl, --C(S)NH.sub.2, or a --CH═NOH
group,'''
so it looks like you may be able to use pool algecide as a leveling agent. I don't have any thiourea as suggested above by Dr Schnufflez. having to
keep up maintenance on my pool I remembered the algecide. it makes small drops/beads of water float around on the surface of the pool when you pour
it in from any height. so no surprise it may affect the surface interface.
Captain* Liquid Copper Algaecide
http://www.sepro.com/documents/Captain_MSDS.pdf
Active ingredient:
Copper (II) Carbonate Basic 12069-69-1 15.9
Inert ingredient:
Proprietary Amine Proprietary 10 - 30
Proprietary Amine 2 Proprietary 10 - 30
looks like it complexes with the insoluble basic copper carbonate. I'm gonna have to give it a try some time. would be nice if it works, one less
chem to buy. I may have to bust out the power supply.
-violet sin-
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Hockeydemon
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Violet Sin thank you! That is exactly what I wanted.
I too don't know how to get my hands on thiourea without paying quite a bit. I've been trying to find another leveling agent similar to the one you
provided because it seems to only come in 1 gallon jugs for over $50.
I can't find anything with copper(II) carbonate, but I can find a few copper algaecides. What about an algaecide that is ~50% Triethanolamine complex
with copper sulfate? I'd like to buy the smallest quantity possible since I don't need that much, and I don't own a pool.
---
DrSchnufflez: Is there no way around the brown silver layer?
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Hockeydemon
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So I have been looking around at electroless plating because I still like the idea of silvering some things for fun, but I more or less didn't find a
solution to make a nice silver solution. There are different compositions such as using silver cyanide rather than silver nitrate, but I can't find
much on it's aesthetic benefit.
I did stumble upon a detailed .pdf on electroless copper plating, but I can't bloody figure out if it is applicable to what I want it for. 90% of it is in regard to
electroless plating of other metals. At the very end (pg322) it talks about non-conductive materials, and adhering a palladium or tin colloidal to the
surface to induce the catalytic plating. The only reason electroless plating seems ideal is because it deposits a uniform coating rather than an
uneven one like electroplating does.
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DrSchnufflez
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Thiourea is a common photochemical, well at least in Australia it is
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violet sin
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the one I have is actually "all-clear : green algecide". copper content is 7.4% and on the MSDS it says it is a mix of triethanolamine and
monoethanolamine with copper carbonate (no percentages listed)... it's not the same one I listed above w/ the MSDS. it is the concentrate in about 1l
bottle for 12 dollars at ACE. there is a smaller concentrate bottle for like 8.99$ but I haven't looked up the MSDS on that one yet. it is worth
a try for only 9-13$. I am busy with other things at the moment but should try here in a day or two. still extracting K2CO3 from banana's for fun,
ATM reducing ash leach sol to weigh soluble salt.
here is the MSDS for the 8.99$ concentrated bottle. sounds like the smaller one might fall more in line with the patent above.
http://www.homedepot.com/catalog/pdfImages/b7/b773641a-a240-...
----QUATERNARY AMMONIUM COMPOUNDS, BENZYL-C12-18-ALKY 13-17%
----Alkyl dimethyl ethylbenzyl ammonium chloride 13-17%
the patent I listed suggested some Cl- in sol and I seem to remember seeing a tip to clean copper bottom pots that supported the idea. when removing
the tarnish from a copper pot, vinegar works slow. but if you add a pinch of salt it clears the surface almost immediately. the patent suggests a low
concentration, 0.03 - 0.1g/l solution. nurd rage has a vid that shows the increase in activity, but he uses a LOT of salt.
http://www.youtube.com/watch?v=H4N-iGvYrbM
this may help the leveling agent work more effectively and possibly prevent inclusions.
-Violet Sin-
edit- what is the thiourea used for there doc? like developer, fixer, etc..
[Edited on 13-6-2013 by violet sin]
[Edited on 13-6-2013 by violet sin]
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DrSchnufflez
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Not sure as I haven't got a darkroom but it's said to be used to tone silver based photos. It's also in some metal polishes I think, along with
sulfamic acid
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Hockeydemon
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Okay so I ran an experiment earlier today, and it ended up being a bit of a failure. My electrolyte solution was 165g copper sulfate, 45g sulfuric
acid, .1g sodium chloride diluted to a 1L solution.
I then sprayed a rock with conductive graphite paint, and let it dry. The anode was 18 gauge copper wire. I unfortunately only had copper wire for the
cathode as well, but this was insulated so only copper wrapped around the rock was exposed to the solution. I ran this at 12v/2amp for a few minutes,
and got bored so I bumped it up to 12v/40amp. This drastically increased the progress, but the only thing that was happening it the Cu(II) ions
deposited on the exposed copper cathode. The reason why is obvious, but I was not really impressed with how it deposited either. It was a mushy copper
dust that kind of just kept falling onto the same spot. There was no real depositing onto the rock at all, except maybe a grain of rice size spot
under where the copper cathode wire was wrapped around.
I then abandoned the rock, and copper cathode entirely. I grabbed ribbon of staples for a staple gun (only readily available metal thing I found lying
around). I used this as the cathode, and stuck with a 12v/2amp charge for awhile, and let it do it's thing. The copper deposited onto the ribbon of
staples, but in essentially the same manner. It was easy to just wipe the brown/red copper dust that essentially coagulated onto the metal ribbon.
I did not add a leveling agent because I have not had a chance to get one.
Any suggestions based on the above?
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watson.fawkes
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What's the resistance of your cathodes vs. the resistance of the graphite coating? Where will be current preferentially flow?
Either insulate the cathode from the electrolyte or don't submerge it in the first place.
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Hockeydemon
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| Quote: Originally posted by watson.fawkes | What's the resistance of your cathodes vs. the resistance of the graphite coating? Where will be current preferentially flow?
Either insulate the cathode from the electrolyte or don't submerge it in the first place. |
I don't have a quantitative answer for the resistance of the cathode vs graphite coating. I know that the current preferred the cathode over the
graphite coating. The cathode was just copper wire spooled around the graphite coated rock very tightly.
How can I insulate the cathode/not have it submerged, and the process still work? Wouldn't this prevent the entire system from working because the
Cu(II) ions aren't being attracted to anything?
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watson.fawkes
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| Quote: Originally posted by Hockeydemon | I don't have a
quantitative answer for the resistance of the cathode vs graphite coating. [...]
How can I insulate the cathode/not have it submerged, and the process still work? Wouldn't this prevent the entire system from working because the
Cu(II) ions aren't being attracted to anything? |
You can look up the material properties of graphite and
copper and compare the conductivity.
I spoke hastily. You want to insulate the cathode conductor (previously: copper wire, staples) and make your coated rock the entirety of the cathode
in electrical contact with the electrolyte.
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phlogiston
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As several people mentioned, the current density is important. You are depositing a large amount of copper on a tiny surface very quickly, and as a
result you don't get a nice smooth coating but mush/powder.
Look up what it should be and regulate your power supply somehow. The idea with the light bulbs could work. You need to measure what current you are
actually running through the cell.
| Quote: | | I ran this at 12v/2amp for a few minutes, and got bored so I bumped it up to 12v/40amp |
You need to have more patience.
[Edited on 18-6-2013 by phlogiston]
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"If a rocket goes up, who cares where it comes down, that's not my concern said Wernher von Braun" - Tom Lehrer |
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