Wednesday, November 11, 2009

Electro plated cranium anyone?

So I convinced Amy (of Bee Girl Metal and my heart) that she should dig out her electroplating machine to plate her own work, instead of paying the rather steep price to have someone else do it.

To be honest, I think I had her get it out as much for me as for her ... I had purchased a bunch of mink skulls that I wanted to try plating as an experiment for a burning man idea.

So, after the dust settled from Pumpkin Prowl, she took over the kitchen for her evil experiments and I watched, learned, and starting sneaking in my own plating experiments (not really, but it sounds more mysterious that way ... ).

First, I was slightly surprised that the machine was just a big AC-DC adjustable linear power supply (0-30 volts, 20 amp max output).

I mean ... I wasn't actually THAT surprised, since I already understood the fundamentals and I had done electroplating in some grade school science class with a couple batteries, but I really did presume that a commercial grade machine (even an archaic one) would be more than a DC bench power supply. So, probably half of the people that will ever read this already have a commercial grade plating machine in their workshop or garage ... including myself.

Electroplating is just strange enough that it balances between science and art. The instructions on the bottle of solution are just simply vague, and a little thought and experimentation will improve the results.

The setup is relatively simple:

* Electroplating machine (AC-DC bench supply, 2-4 volts is working range of all solutions below, 5amp minimum, 10amp would be more ideal to prevent fuse melting).

* Pyrex glass containers (lab or more common oven cookware). You will need one per solution, and if you are plating metal, you will need one for the cleaner (if you choose to use it). These all need to be big enough to immerse your object into. If you use oven cookware Pyrex, you might want to make sure that it can be placed directly on a heat source ... it often says what it is safe for use with on the bottom of the Pyrex container itself.
  • DO NOT USE GLASS! Amy did not heed my warnings on this, and she did actually explode a jar of cleaning solution (caustic!!!!) all over the oven. I love that girl ... such a mad scientist!!!
  • After that fun and excitement, I added another pyrex container to the mix, one large enough to hold all of the others while they heated (see next step).
* Heat source (some solutions so not require heating, bright copper, for example, does not). 180F was maximum needed temp for our purposes. We used the stove top and a thermometer. After the jar explosion, I added a larger pyrex cookware container to the mix, one that all of the others could fit in while they were on the stove. To this container (a shallow baking dish) I added water, presuming that it would govern temperature change better on the glassware ... and it worked great!

* Solution ... this is the expensive part ... or can be depending on the metal of choice. This is the dissolved metal concoction that the object will be plated in.

* Anodes that match your solution needs. Sometimes this is the same material as the plating metal, sometimes it isn't. The anode required should be listed on the bottle of solution. Between what both of us were working on, we needed:

  • Stainless steel anode for the gold solution
  • Nickel for the nickel solution
  • Pure copper for the copper solution
* Copper wire to connect plating machine to solution anode and cathode to object

* Optionally, if what you are plating is not metal, then you will need conductive paint (brush or spray on are available). You will coat the object in this so the metal has a conductive surface to form on.

The variables to consider are the following:

* Voltage - increasing the voltage speeds up the process, however, it can also lead to "chunky" results (a sometimes desirable thing ... referred to as electroforming). In the case of copper, I was actually trying to electroform large growths (at 20+ vdc), and after a certain point, the copper that was forming was not actually adhering well to the object ... giving the object copper "hair" that could be washed off.

* Time - The longer the bath, the thicker the plating

* Temperature - Some solutions need to be heated before use (both nickel and gold do). It has been hard to get a bead on the effect of dropping temperature is, but it is on the suspect list of blackening that was happening to both nickel and gold in longer bath output.

* Proximity to anode - While this would be an electrical variable, this is listed more in relation to the object's three dimensional space versus anode proximity. The part of the object facing and closest to the immersed anode will simply plate faster. It is also possible that some of the blackening that occurred (on at least the nickel) was related to this variable.

I wouldn't say I have the processes down just yet, but it has been a fun journey so far!

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