Introduction: No-Fail Metal Plating With Kitchen Chemistry
Watch the video to see metal plating in action as I Nickel plate a 3D printed Mjolnir (Thor hammer) and do a super fun Thor cosplay but with REAL LIGHTNING!
ALSO! For a limited time you can WIN my custom-made Thor hammer! All raffle dollars go towards a non-profit called Reinvented Magazine that works to inspire young women to get involved in science and engineering.
Metal plating is the process of adding a thin layer of metal to an object. Companies like Caswell Plating sell easy to use metal plating kits, however while those kits do produce a high-quality plating, the chemicals in those kits can include Sulfuric Acid, Nickel Chloride, and other chemicals that are considered toxic or extremely dangerous by the NFPA.
I challenged myself to come up with a "Kitchen Chemistry" version of those plating kits that mainly uses vinegar and salt. Many people have done this, but there are hundreds of different recipes out there, so how do you know which one is best? I conducted a systematic analysis of every tutorial I could find, and I also read the books and consulted with experts so that I can present to you this optimized tutorial.
In my opinion the biggest advantage to using the more dangerous chemicals is that your plating will go faster. So if you are not in a rush, and you would like to use less dangerous chemicals, this Instructable is for you!
- [Quantity 1] Sterilite 32 Quart Gasket Box (this is your plating tank)
- [Quantity 1] Sterilite 28 Quart Storage Box (this is your catch basin)
- [Quantity 1] Titanium Immersion Heater (to heat your bath)
- [Quantity 1] Submersible Pump (to agitate your bath)
- [Quantity 2] Expanded Titanium Mesh (to build your anode baskets)
- [Quantity 1] Adjustable Power Supply
- [Quantity 2 Pairs] Banana Cables With Alligator Clips
- [Quantity 15 Pounds] Nickel Anode Crowns (this is your plating metal)
- [Quantity 1 Can] Nickel Conductive Paint (to make your parts conductive)
- [Quantity 1 Bottle] Sodium Saccharin (bath chemistry)
- [Quantity 1 Bottle] Plain Non-Iodized Salt (bath chemistry)
- [Quantity 8 Gallons] Pure White Vinegar (5% Acid) (bath chemistry)
- [Quantity 2 Feet] Copper Pipe, 3/4 inch trade size (to hang your parts from)
- [Quantity 25 Feet] 10 Gauge Bare Copper Wire (to make part hangers)
- [Quantity 25 Feet] 18 Gauge Titanium Wire (to connect electrodes)
- [Quantity 1 Tub] Polish
Step 1: Make Your Anode Baskets
Bend your titanium mesh into a tube. Do this with both pieces of titanium to make two tubes. If you have a fancy sheet metal roller you can use that, otherwise just bend them with your hands. Use small cable ties (also known as zip ties) to bind the edges together.
The tubes need to be shortened to fit inside your tank even when the lid is closed. Use a marker to mark where you want to cut the tubes, and then cut them to length with metal shears. Optionally, you can get a more even finish on this cut if you remove the last few millimeters with a sander.
Next the tubes need to be covered in cotton cloth to act as a filter bags. Take any cotton cloth (I used white flannel) and cut two rectangles (one for each tube). The width of the rectangle should be two times the tube height, plus the diameter of the tube, plus an extra inch for slack. The height of the rectangle should be the circumference of the tube plus an extra inch for slack. Fold this in half and sew the edges, then slip your titanium mesh tube inside this cotton bag and use cable ties to secure the bag to the outside of the tube. Do this with both tubes.
Finally it's time to attach your anode baskets to your tank. Use a marker to mark two hole locations, then drill the holes in the inner lip of the tank. Note that this won't create holes in the tank that would cause the bath to leak out, because you're only drilling through the inner lip and not the outer wall of the tank. Finally use small cable ties to secure your anode baskets to opposite corners of your tank.
Step 2: Make Your Cathode Bar
Use a pipe cutter to cut your copper tube to just fit inside the outer walls of your tank.
Next, use a rotary tool, bandsaw, or other machine of your choice to cut notches in the tube where the inner lip of the tank will fit.
Finally, press the tube onto the inner lip of the tank. The tube should go down far enough onto the inner lip so that it won't prevent you from putting the lid on the tank.
Step 3: Prepare Your Tank
Put your plating tank inside the larger catch tank. The idea is that the catch tank will help catch leaks before they flood your shop. A leak is rare and unlikely, but I believe it's better to be safe than sorry.
Fill your anode baskets with nickel crowns.
Put your heater and pump into the bottom of the tank
Put 5 gallons of vinegar into the tank, turn on the pump, and set the heater to 40 C (104 F).
Step 4: Prepare Your Bath Chemistry
Open one more gallon of vinegar (this should be the sixth gallon). Put 114 grams of saccharin (19 grams per final Gallon of bath) and 138 grams of pure table salt (23 grams per final Gallon of bath) into a gallon of vinegar. The salt is there to make the bath more electrically conductive, and the saccharin is there to act as a leveling agent to achieve more even metal plating. Shake vigorously and add this to your bath. You should now have a total of 6 gallons in your bath. The other gallons are to replace the vinegar that evaporates over time.
Connect titanium wires to your anode baskets by threading them through the holes in the basket and then firmly twisting them until they are snug. Connect one wire to positive and the other wire to negative. Set your power supply to 1.5 volts, 0.25 Amps, and let it run for a couple days until the bath turns this nice dark green color.
Once this is finished, remove the negative lead and connect both baskets to positive leads. Wrap a titanium wire around your copper tube and connect that to negative.
Step 5: Paint Your Part With Conductive Paint
Your parts need to be conductive in order for electroplating to work. So, you will need to coat your parts in conductive paint.
I suggest three even coats of paint, with time to dry, followed by a very thorough and careful sanding job. Start with 220 grit sandpaper, follow it up with 800 grit, and then finally 2000 grit. This will take a long time, and it's the most critical step. If you don't do a very good job sanding, your part will not polish into a nice shiny metal finish later on, no matter how much polishing you do.
Wear gloves while you're doing this so that you don't get sweat or grease on your part. With thin gloves you should be able to feel much of the surface texture. If you see or feel grooves or ridges, add more paint or spend more time sanding respectively until the surface is completely smooth. You will only get a shiny metal finish if your part is super smooth before putting it into your plating bath.
Step 6: Plate Your Part
Cut a piece of 10 gauge copper wire and bend it into a hanger to hold your part. For most parts you want a "cradle" like you see in the photo of the hammer handle. For other parts like the hammer head you may choose to create a coil shape to push the part into the bath (relying on the buoyancy of the part to keep it snugly held).
Wrap the other end of the hanger wire onto your cathode bar (the copper tube). If the bar has been covered in green crystals from the bath, you'll want to use a scouring pad to clean it off so that the hanger wire makes good electrical contact with the copper tube.
Set your power supply to a maximum of 0.9 Volts, 0.2 Amps to start with. In commercial plating you would calculate the surface area of your part and multiply it by a constant to get the desired current in Amps, but for home plating purposes where cycle time is not critical, you want to go "low and slow" meaning keep the current relatively low and just let it plate for a long time. This will give you a good plating. You can try increasing the current (in Amps) if you'd like to go faster, but once you see the plating start to crack and peel up off the part you'll know that you are using too high of a current. In contrast if the voltage goes too high, your part will end up with rough or burnt looking plating. So feel free to experiment, but consider starting with my recommendation.
Rotate the part inside your hanger every 6 to 12 hours to prevent "shadowing" - the effect that happens where the surface area under the hanger doesn't get plated. Plate for 1 to 3 days. This is a long time, but it's not like you have to really do anything during this time. Just get excited to see the results!
Step 7: Polish Your Part
Once you take your part out of the bath, rinse off the bath by pouring a little distilled water over it. This will return most of the chemicals back to the bath. Then take it over to the sink and wash it for a long time.
If your part feels rough, you can use 800 or 2000 grit sandpaper to smooth it. Once it's smooth you can proceed with polishing.
Follow the instructions for your polish. Plan on spending a good amount of time polishing your part. The more you polish it, the shinier and nicer it will look. I polished my parts by hand, but you can try using a polishing or buffing wheel if you'd like. Just be careful not to let the plating get too hot as the buffing wheel rubs it, because if it gets too hot it can delaminate from the part or it could cause your part to melt or deform.
Step 8: Enjoy Your Metal Plated Part
Have fun with your metal plated part!
I used my metal-plated Mjolnir (Thor's hammer) for a Thor cosplay involving some giant musical tesla coils. The plating stood up to some massive lightning bolts and that gives the whole process my seal of approval.
Second Prize in the