Copper plating aluminum enclosure experiment results

[John Lyons]

Thanks!
I have been trying to create some continuity in doing this but it's pretty hard.
I just did a run with a DOD aluminum box and I could only get a charcoal black out of it. Very Frustrating!
Looked a whole lot better than the purple and white (toy looking) box it was before...

John

[brett]

Ok
I'm not a chemist, but I've picked up a bit along the way.

You probbably already know that one electrode is supplying electrons and the other is accepting electrons, and that the charge is carried through the bath by soluble ions.

There are going to be three or four main factors affecting the outcome. 
The first one to consider is what metal ions are floating around in the bath.  To make sure that it is divalent Cu, make sure that the +ve electrode is pure copper.  Not brass or bronze, but coppper.  It probbably doesn't need to be very large because a small amount goes a long way when plating.

Another factor is the REDOX state of the bath.  REDOXis short for reduction-oxidation.  From the name you can see that oxygen (and it's friends the oxidising agents) are important.  At a guess, I'd say that oxygen and chlorine are your main enemies in this bath, because they could easily turn the object blue-green.  All you can do is use really clean water (rainwater would be goood), and make sure that the amount of current you're using is high.  There might be anti-oxidants that you could use (such as ascobic acid or Vitamin C), but they're probably not needed.

Another factor is the pH.  You don't want to be etching the object. Not just because etching itself is a great problem, but because aluminium is much more easily corroded at low pH than copper, which would pollute the bath with aluminium ions.  A small amount (approx 1 g/L) of potassium hydroxide or sodium hydroxide (care!) or a similar alkali (hydroxide, not carbonate) will help.  They're available at the harware store or supermarket.  At a guess, I'd say a good target pH would be 9 to 10, because aluminium is fairly stable at that pH.  Don't go too high (pH12), or it will dissolve into aluminate ions.

Temperature might be a factor.  The solubility oof oxygen goes down with temperature, while the solubility of the metal ions goes up.  So warm might be better than cold (but that's just a guess).

cheers

[John Lyons]

Thanks for the info brett!
Obviously I need to read more about this as a lot of what you mentioned is greek to me (no offense greeks out there!)
I have only actually plated something once and that was a total fluke and I didn't follow any procedure pre se.

I have been mainly trying out the "chemical staining" or passive plating by using copper sulphate, sodium carbonate, and a small amount of Cream or tartar (not sure of the  chemical in that off hand).

I've gotten colors such as purple/blue, brown, orange, actual copper, black, and various shades inbetween. Now I just have to be able to get control over what produces what. This ties in with bretts post. The water PH, heat...

The elements here are heat through boling water, Adding in a half teaspoon of copper sulphate and a sprinkle of sodium carbonate to enough water to cover the box in a small rectangular plastic dish. The reaction is some frothing over about 30 seconds and then adding in more of the same chemicals.
The main problem is that I don't have a several boxes to test it out on in order to get some feel for what does what and to compare the boxes to compare results. The metal make up of each brand of box makes a difference as well. Aluminum, zinc, etc etc

Dragonfly has sent me some boxes to do for him. Hopefully I'll get a chance to experiment here. I'm going for the Rusted out look like in the speckled box in the first post.

I would like to get a plating kit and try that out as it's direclty applied in concentrated form. Electrodes, wipe on copper plating gel...

Here's a pic of the Pewter like finish I did on a really ugly purple DOD analog delay. Not the effect I was looking for at all, but....
fairly boring huh!
Now to ditch those ugly knobs! Not much can be done with that footswitch..tried buffing it out with steel wool to loose the plastic shine.




John

[runmikeyrun]

this looks really cool!!!!  another great DIY thing to mess with.  I guess i'm off to the thrift store for some old pots.  I'll probably use the camp stove outside as i don't think fumes in the house would be a good idea.

careful guys, a news report this week stated that they think one of the main causes of Alzheimers, among other things, is copper poisoning.  Interestingly, they said the main source of copper in people's diets are from vitamins  but it has been identified as a possible cause.  Things like copper piping may also be to blame but at this time they're not recommending you go rip out all your plumbing.  Other causes are linked to other heavy metals like lead and aluminum which we work with frequently.  Metal poisoning is also responsible for acute nerve damage as well, but we already knew that!  So be careful, masks while sanding and fans/good ventilation while soldering, etching, and plating. 

If you're looking for mass production or perfection, it might be worth checking with a local plater to get your boxes on a hook with their next plating run.  I had some motorcycle fenders and parts chrome plated a while back and it was about $30 for a fender, so a box shouldn't be too much. 

p.s. some studies i read around the time of the mad cow scare said that as many as 15% of all diagnosed Alzheimer's cases could actually be BSE that was dormant because the disease can take 10 years or more to become active.  Some people also think aluminum in deodorants is linked to alzheimers and possibly breast cancer (i use a salt based one from the health food store because i'm paranoid).

[Taylor]

I realize this is my second necro-post of the day, but John, did you ever get any farther with this? I really like the look of this, in fact all the different effects you got were pretty cool. I'm just wondering if you got any more precise with it and maybe had some updated thoughts on how to get slightly more predictable results? Is that a Hammond box in the first tests?

[John Lyons]

Taylor
The box in the test was a 1590NS.

It's highly inconsistent and takes a while.
It's also very unstable and needs a clearcoat.
Did I mention that it's a pain in the ass as well
That said...here are a couple examples.

[Taylor]

Wow, those look really nice. Did you hit some of those with a torch? That burnt, red on black look is amazing. Any chance you'd start offering that as a service alongside powder coating?

[John Lyons]

The whole process is chemical and experimentation.
Two and three tries to get something that looked nice.
Some other copper processes I do torch but not these.
Everything I make I sell for the most part.
I'd probably sell them for $50...

John

[Joe]

I found this formula in one of my antique books. Here is a simplified version:

1 cup Water
1 tsp Copper Sulfate (Root Kill)
1 tsp Sodium Carbonate (Arm & Hammer Washing Soda)
1 tsp Cream of Tartar (Grocery Store Spice Section)

Boil the aluminum in the solution. Higher temperatures produce more oxides. A solution of vinegar and salt will remove the oxides but may also remove the entire finish.

The boxes look awesome John!

[John Lyons]

Joe
Your post years ago was the inspiration!
I have tried the recipe you mention above
(I asked you for it a while back...)
It can have some cool results but still pretty
unpredictable. That process is for an all over/uniform
look...My process is a cross between painting and
selective removal rinsing as well as etching.

[Ben N]

Great thread, cool stuff, John.

I'd say this would be of considerable interest to those about to build a Burst Box. 

[glops]

Here's my result that came out with nice results.  My camera is not good but this gives you an idea.  The copper is nice and shiny...

I followed John Lyon's on page one except I used regular baking soda because I couldn't find washing soda.  I tried this a few weeks ago with different/less pleasing results.  This time I added more root killer (maybe 3/4 teaspoons of rootkiller) and let it cook for roughly ten minutes and then added the baking soda and some tartar.  The box got pretty dark and then I rinsed it and wetsanded it with 320 grit.   By doing this it seemed to let some of the copper shine through.  I prepared another bath and repeated this process 4 or five more times.  I'm really happy with the final result and want to do more.

What would be a good clear for this.  I am going to do a thick coat of lacquer unless someone think there's a better solution...

Thanks!

[Taylor]

Glops and John, when you guys do this do you cook it inside on your stove? Or outside on a hotplate or something? I'm assuming that breathing copper fumes is extremely toxic...

[glops]

Hi Taylor,

Yep, on the kitchen stove!  Probably not the best idea but I open the door that is right next to the stove and make sure windows are open.  I also wear
a respirator.  Ideally, it would probably better to not do this at home.  Since, I have only done it a couple of times I'm not worried.

My last experiment didn't go as well.  I used a small Hammond box and payed more attention to the enclosure and not the plate.  The plate came out
perfect but I ended up sanding the copper off.  What I was left with was discolored blackish aluminum.  Sanded some of that off and it looks cool and old...

[G. Hoffman]

I get some parts custom plated for my guitars (NOT something I would ever try to do myself, but that's me!).  One thing about the process, though, is that if you want your final product to have a mirror bright/shinny finish, your base material needs to be shinny.  Basically, as I understand it, the plate will follow the contour of any scratch/dent/whatever that you have, no matter how microscopically small.

Now, as a guitar builder and finisher, I've got some experience making things shinny, so I do all that myself, and save myself about 2/3's of the cost with my plating shop.  Whatever work you've needed to do to make these things at all, you can count on a lot more if you want them to a mirror polish.


Gabriel

[Taylor]

I think this process is more about that funky industrial/steampunk look than trying to get something perfectly smooth - if I was after that it would be much smarter to get a professional plater to do it.

[G. Hoffman]

I think this process is more about that funky industrial/steampunk look than trying to get something perfectly smooth - if I was after that it would be much smarter to get a professional plater to do it.

I wasn't going to say it, but....

It would probably be pretty pricey to get just one made, but if someone did 50 (and did the polishing themselves) it probably wouldn't cost too much (per box, of course).  Though the labor of polishing them all yourself would be an awful lot of work.  And you would need them drilled before you plated them.


Gabriel

[tomfoy]

This is a great thread, thanks all of you!

From what you guys have posted, it seems like any oxidation I want to happen happens during the plating process, unless I sand off the outer oxidation and then hit it with something else. What I want is a a blue-green copper patina; I wonder what putting some bleach in there would do. I've read that this is dangerous, though, because bleach can release chlorine gas, so watch out. Another suggestion I see a lot to get a patina is miracle grow and water; another is ammonia and salt (don't mix ammonia and bleach!)

http://www.sciencecompany.com/patinas/patinaformulas.htm#7
http://www.finishing.com/57/20.shtml

[chicago_mike]

PROBLEM THOUGH:

I talked to a few geeks in the know of copper plating aluminum. While it can be done, take a knife and you can scrape the copper plating off in one swooth...it will just come off in one roll pretty much.

Etching the aluminum only works so so because you still have to try to bond 2 disparate metals. If the enclosure was stell we'd have much better luck.

Basically what happens is the copper doesnt bond to the aluminum and theres a gap of air, as miniscule as it is that seperates the copper from the aluminum. Hence taking a knife and easily scraping it off.

If you guys can get it to bond without flaking off...thats some good work!

[glops]

Chicago Mike-

I definitely don't know how it works and simply used John's formula.  But it definitely doesn't "bond" well all of the time.  My experiments were pretty consistent in getting a copper color but I found the best results were to simply repeat the process over and over, wet sanding with a high grit between processes.   Usually the first couple of steps yielded in a dark brown discoloring of the aluminum.  I would sand very lightly and get some shiny exposed copper and then doing up to 4 more processes.  Some of the copper would flake off but the next process would fix that.  The picture I posted above was taken on an iphone and doesn't really show good detail.  It was really pretty and looked like I had sanded a copper box that had been buried for 100 years.

It's too bad that the clear coat I put on it knocked the shiny appearance down a notch.  It looks cool as a finished pedal but if I do it again I'm going to use a different clear coat.

-Richard