Zinc Electroplating

grepper

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First off let me say that I am by no means a chemist. If I had a chemistry class in High School, I don't remember any of it.

This is a summary of what I've read.
Electroplating occurs in an electrolytic substance of free ions which are the carriers of electric current. Here this is, Epsom salts (magnesium sulfate) and Vinegar (acid). Connected to the positive of an electric power source an anode made of zinc, attracting negatively charged ions causing Oxidation. At the negative side of the power source is the cathode, attracting positively charged cations, moving ions away toward the anode. Here it provides electrons to the cations to convert them back to the parent metal (zinc). This process is called reduction.

In short, the zinc leaves the positive side and binds itself to the negative side.

Supplies:
Various measuring cups, postal scale for measuring by weight, copper pipe and wire, and a plastic tub.
Epsom salts (pharmacy section of your local grocery store)
White Vinegar (baking section of your local grocery store)
Zinc Sulfate (available online, reduces time and increases quality of the plating)
Karo brand corn syrup. (baking section of your local grocery store, contains glucose that acts as a brightener by keeping the zinc crystals in alignment)
Zinc Anode, (online or in home stores in desert climates as it's used for evaporative (swamp) coolers)
A DC Power Supply, low amps (1A to 300mA).

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Solution:
4.5 liters water
300 grams Epsom salts
100 grams zinc sulfate
200ml of white vinegar
1/3 bottle of corn syrup

Stir in plastic tub till dissolved.

Setup:
Suspend Zinc Anode(s) in solution and hook up to positive of DC Power Supply.
Have copper bar go across top of the plastic tub, copper wires wrapped around bar, so you can suspend parts in solution without touching Zinc Anode(s).

Electro zinc plating:
Strip metal to be plated. I soaked my parts in vinegar for several days to dissolve the rust, and then cleaned with a wire brush and sand blasted. Finally I wiped my parts down with denatured alcohol.

My first try, this is a pivot shaft from the center stand of a 75 cb750 I'm restoring.
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After sand blasting
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Suspend part in solution with copper wire.
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Attach negative power supply to copper bar.
In about 1 minute your Anodes and part will bubble.
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In 5-10 minutes disconnect power and inspect part. It should have a milky coating of zinc. Clean with wire bush and/or steel wool.
You may need to repeat for a thorough covering.
Then polish to a shine.
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Some more parts, rusty engine mount bolts
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After plating and polishing
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Part of the center stand, connects frame to spring.
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Rear brake arm
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Head nut
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All the parts I did today.
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All these parts are from a 1975 CB750K I'm restoring. All were dirty, rusty and pitted. Now plated to hold up to the elements of an other 40 years.:thumbsup:

This box of parts took me the better part of a day. The process is time consuming. I plan to buy common sized stainless steel nuts and bolts from the hardware store. But for the stuff that is specific to the bike, I plan to zinc plate.
 
Thank you, much less mucking about than using the Caswell kit. Was getting ready to send an order to the electroplater but will give this method a crack soon.
 
Very well done, this needs to be printed-out for my shop...
I acquired an electroless nickel plate kit from a gunsmith supplier awhile back, advantage is simpler
to do and harder coating, but very expensive, would take gallons to do your project.
I like this method better...
 
Cool beans, great write up!
Are you planning on top coating the zinc that shows?
I keep meaning to do plating but haven't got a round tuit yet.
This might help get me off TDC, small steel carb parts are always needing a spiff up.

Marine stores often have various zinc anodes too.
 
... Are you planning on top coating the zinc that shows?
...Marine stores often have various zinc anodes too.

Not sure what you mean about top coating??

Yeah, Marine stores would have the anodes. No shortage of boat stores here in Michigan I also considered zinc strips that you use on roofs to prevent moss growth. These anodes cost me ~$10 each online, I used two. I have less than $30 in supplies here (tub and copper I had), and have enough to do several rounds more of plating.
 
Sweet write up. Never seen that done before. Quick question for ya, Does this eliminate the need to sand blast? Or did you do that before doing this with all those parts?
 
Sweet write up. Never seen that done before. Quick question for ya, Does this eliminate the need to sand blast? Or did you do that before doing this with all those parts?

Yeah, what tony said. The zinc sticks to metal, not rust... You should get the parts as clean as possible first.
 
Wow, I'm glad I saved my old RV hot water heater anode rods!
Sandblasting should make them useable...
They're about 3/4" dia x 9" long, available online, $10 - $15.
 
Heads up; not all water heater anode rods are zinc.

Magnesium and aluminum are more common in water heaters.
 
Could this be done to the inside of a fuel tank? That would fight one bad thing about ethanol fuels.
Leo
 
In a different thread, one of the pre cleaners for a coating, or a derusting process like this one, is said to leave a zinc phosphate coating. Does anyone remember that?
 
Could this be done to the inside of a fuel tank? That would fight one bad thing about ethanol fuels.
Leo
No, as the fuel and zinc are not compatible long term. I looked into this years ago when I was building a fuel tank for a boat. It just isn't done.
 
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