Hello with two salts you can make Rainbow and colored spoons by electroplating a solution of copper acetate and Potassium copper Oxalate in tap water and running electricity across the spoons. Chrome Stainless steel (18 parts Chrome, Usually 0-5 parts Nickel).
In theory, the acid excess oxalic acid and acetic acid added to copper (II) acetate will CAUSE the copper to plate more effectively than other types of basic copper (II) sulfate plating with just water and copper sulfate. The acid a weak acid either acetic acid or Oxalic acid acts as a buffer keeping the solution fairly acidic and helps the copper slowly stick more to the steel.
The steel must be clean and not touched. Dirty steel will NOT work as well.
Keep the voltage at 5 volts to 0.50 Amps anything higher than that will increase the likelihood that the copper will form a mushy flakey appearance. This is also true about the acidity of both Oxalic acid and Acetic acid.
0-30 volt 0-3 Amp DC Power Supply.
1L beakers-2 L beakers., 1 L dish or bowl to evaporate the solution of both copper acetate and Potassium copper oxalate.
A good 120 dollar Hot plate (Optional is stirring capability- if not you may need to stir it manually).
Clamps and rods and Lab support Rod with base (Several).
Filter paper for separating Copper(II) acetate from other salts.
1000 g plus or minus 0.001 g Jewelry Scale for weighing out the chemicals.
Optional digital thermometer to record temperature.
Potassium Copper Oxalate.
You need either Potassium Oxalate or Potassium Hydroxide and Oxalic acid. 15 g Oxalic acid, 20 g Lye.
Copper (II) sulfate Pentahydrate salts. (35 g Copper sulfate for Potassium Copper oxalate salt.)
Copper (II) acetate. Requires 47.9 g of Copper sulfate.
Sodium acetate Anhydrous 100 percent. (100 g).
In 600 ml it makes 35 g Copper Acetate. 1 percent loss in cold washes is expected.
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Step 1: Theory and Precautions With Chemicals (Including How to Make the Chemicals).
Normally acidity with copper sulfate Ph for 1 mole of CuSO4*5H20 is about 3-4. However, we need to get the solution to work to be quite acidic. Lots of weak acids like 1 Mole Phosphoric acid, 1 Mole Sulfuric acid, and even 1 Mole Hydrochloric acid can be used.
Hydrochloric acid in electroplating may produce Chlorine gas so you should work with weaker acids like Oxalic acid that act as a buffer and allow the copper to slowly deposit onto the metal. If the acid is too high (Like 1 for example) this may not work very well.
Stronger acids may have strange and undesirable results.
The acid actually creates micropores on the steel causing the copper from the salt to plate directly to the steel. The acidity from oxalic acid and acetic acid (glacial acetic acid) 6 ml produce a strong acid that with a buffer (Sodium acetate) allows the copper to deposit more smoothly with current and voltage.
I tried to find info on Potassium copper oxalate but no info on youtube. The form is where I got the info.
Next, I will show how to make Copper (II) Acetate in two ways.
Lye (KOH) is very corrosive and destructive to tissue. Oxalic acid is a strong acid and can cause serious burns on contact especially when HOT. Copper sulfate is poisonous. Never dump either copper acetate or Potassium copper Oxalate down the drain.
You can re-use these solutions.
Step 2: Making the Potassium Copper Oxalate.
Here you need Lye (Potassium Hydroxide), Oxalic acid and Copper sulfate Pentahydrate.
Calculations for making weigh out 20 g of copper sulfate, weigh out 15 g Lye and 20 g of Oxalic acid.
C2O4H2 >>> K2C2O4 + 2H20.
Potassium Hydroxide + Oxalic acid >>> Potassium oxalate + water.
2K2C2O4 + CuSO4.5H20 >>>> K[Cu(C2O4)2].2H20 + K2SO4(aq)+5H2O
20 g Oxalic acid, 15 g Lye and 20 g copper sulfate.
20 g/ 90.03 g per mole = 0.222 moles Oxalic acid.
15 g/ 56.1056 = 0.267 moles KOH times 0.95 (95 percent) = 0.253 moles KOH.
Potassium Oxalate--- 0.222 moles times 166.22 g per mole = 36 g.
Assuming KOH (Lye) is the limited reagent we can calculate the moles of Potassium oxalate.
35 g copper sulfate.
39+ 63.5 + (12*2 + 16*4)*2 = 102.5 + 176 + 36 = 314.5 molar mass complex.
0.2220 moles time 314.50 = g complex…. 69.10 g divided by 2 = 34.9 g Potassium Copper Oxalate.
Slowly add to 600 ml of tap water 20 g Oxalic acid and slowly add 15 g of Potassium Hydroxide (Ideal 95 percent). Be warned that the oxalic acid will get very very hot as the Oxalic acid and the Potassium hydroxide mix stir with Plastic spoons (Not metal) they may corrode and react with the Lye and Oxalic acid.
If you have a stir capability then add a medium stir rod and while heating the solution of Potassium Oxalate with a watch glass remove with gloves carefully and add slowly while the stir rod is stirring at 1 setting about a tablespoon at a time.
As you add the solution have the heat set for 60-70 degrees C. If the temp boils very rapidly the copper salt can be reduced to copper sludge (this would ruin the results). That happened Once with me.
Step 3: Making the Copper (II) Acetate From Copper Sulfate and Sodium Acetate (with No Water).
You require 47.9 g of Copper sulfate and an excess of about 100 g of Sodium acetate. The excess sodium acetate forms sodium sulfate that forms an Insoluble cake on the bottom that can be separated by cooling (it crashes out by changing the solubility of the two chemicals) and is filtered.
Before electroplating, about 6 ml of Glacial Acetic acid was added (Optional but it helps to use it).
DANGER: Glacial Acetic acid is very strong acid and it fumes a lot which is highly corrosive and irritating. Wear a gas mask and don't force the bottle open if it gets stuck.
CuSO4 (aq) +2 NaCHCH3CO >>> Cu(CHC3CO)2 + Na2SO4. 47.9 g divided by 159 (CuSO4)/249.685 g= 30.5 g CuSO4/159 = 0.190 moles in 600 ml times molar mass copper acetate x 181.63 = 34.8 g Copper acetate in 600 ml.
Step 4: Copper Plating for Both Techniques.
Here a video on simple plating mine I added Oxalic acid Potassium salt.
Negative should be the steel and Positive is copper wire I had it in Opposite- Oops.
For both mixtures, the solution should be 600 ml to 1000 ml. Make sure you have a 1-2 L flask for this. Insert Neg for steel for both note that crystals of copper with acetic acid and sodium acetate for the other plating method will oxidize with air exposure giving different results (in color) and epoxy or white urethane like paint is required.
It takes 15-20 minutes at 0.7 Amps 4-5 volts to plate with both techniques. Keep in mind that these chemicals must be neutralized or heated with excess lye to be converted back into copper. Or stored as liquid salt and safely sent to an Eco center.
Never dump these solutions down the drain.
Step 5: Final Remarks for Copper Plating.
This has been an Interesting Project with steel-like Chrome 18, 0 Nickel Stainless steel spoons (Stainless steel (18-0) spoons. The chrome and nickel with a clean plate within 20 minutes can result in interesting results.
For both the copper salts it is recommended that you soak the spoon after 12 hrs of drying into Urethane type lacquer.
This has been a fun project for making art from spoons and electroplating them.