In this example of electroplating I will show you how to electroplate nickles, quarters and dimes with the copper from pennies. Pleases read all the steps before starting.
Since I haven't found a nice instructable on electroplating, I am now making one.
Warning! This is my first instructable!
What you will need:
1-1.5 v power source (old batteries preferred)
some kind of battery holder with alligator clips
small, non-conductive, disposable container (plastic or glass, the small yogurt containers are great)
a weak acid (vinegar: acetic acid, or lemon/lime juice: citric acid)
two or more pennies
quarters, nickles and dimes (almost any hardware you want platted)
time (at least 1.5 hours...I think, 3 is better)
plastic wrap (Saran Wrap)
here is all the stuff I used, the 3000 sq ft platic wrap gets a picture of its own.
Step 1: Fill Your Container With the Acid
First take you job, which will be a quarter for me, and mark its height inside the container - this will be a fill line.
Remove the quarter and fill the acid past the line. If you don't have enough acid, you can add water and dilute it, but do not go past 50% acid (since vinegar and juice is already diluted). I had only half the lime juice I need so I just added more water until the surface was past the fill line.
Step 2: Setting Up the Apparatus
Please preview the diagram below.
First put a penny on each alligator clip. On the positive clip, clip it on the very tip of the penny.
Next put the negative alligator clip as shown in the acid (you want the penny to be fully submerged, this clip will also get some copper plating). Secure the clip with tape (you can run the wire down the out side of the container and tape it on the side).
After you are done that, move onto the postive clip, which will be on the other side of the cup. You want ONLY the penny in the acid - the aligator clip must NOT be in the acid. Again secure the clip so that it will no fall into the acid. (I did this by putting strips of tape like two seat buckles over the postive clip).
Step 3: Help the Copper Dissolve
Since we are using weak and diluted acids, copper will not easily dissolve by itself. We can promote its dissociation by applying voltage across the terminals.
Connect you power supply the positive to the positive clip and the negative to the negative clip. Make sure the two pennies are not touching, you should be able to notice bubbles forming on both pennies. (There should be more bubbles on the negative, fully submerged end).
Wait an hour or two. You can move onto the next step when the acid develops a green tint.
This is a great time to clean your job with soap or toothpaste. This gets rid of dirt and oil that will cause the plating to flake or rub off. (Don't touch your job with bare hands after it has been cleaned. Oh you can also use rubbing alcohol.)
Step 4: Start Platting!
After the acid has turned noticeably green, you can now replace the fully submerged penny on the negative clip with your job, in my case a nickle. Again fully submerge the nickle.
Keep the power connected and wait 10 to 20 mins before disturbing it again.
Step 5: The Result
After about 10 to 20 mins, your job should have a nice plate of copper - if it is coated w/ black stuff your voltage it too high. If there are still uncoated parts, keep the job in a little longer.
DO NOT touch the job. Pull the job out and shake it to remove most of acid on the job. Transfer the job onto a sheet of plastic wrap and wrap it completely trying to remove as much as air as possible. Let it dry (SEALED in the plastic wrap) for several hours before handling.
Step 6: The Final Results
Here the results and the three common coins coated with copper. Like regular pennies, your job will get dull and turn green, if want to keep it for a long time, sealed it with clear spary paint.
Step 7: Help!
Help! My job is dissolving. You probably reversed the polarity.
Help! There no green tint. Either you diluted the acid too much or you battery has extremely low voltage. Do you see bubbles on the negative terminal, if not check your circuit.
Help! I put my job in for <fill in a long amount of time> and it just got dull. You can check your circuit, but its probably not it. Check this page your job must be lower than your plating material on the chart. (If they are too far apart, step up the voltage).
Here is how it works: both metals, copper and nickel, gets dissolved in the acid into positive ions Cu+2 or Cu+ (based on your acid/coin condition) and Ni+2. Since Cu+2 and Cu+ both have a higher or more positive reduction potential than Ni+2 (which actually have a negative reduction potential), Cu+2 or Cu+ will be more attracted to accept electrons from the negative terminal (which is your job). If this happens at high amps/voltage, the Cu+2 or Cu+ will get reduced (accept electrons) from the negative terminal and collect as a black soot-like material. But since we are using diluted acid, which allows low amps, the Cu gets a chance to crystallize on your job before it is fully reduced.
Good Luck Electroplating!