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Zinc plating Bath composition

Updated: 2009 Jul 22

Here is the composition of my four baths. Remember to always put the water in the buckets first, then add the other ingredients. I don't claim the baths to be correct or even good, but they have worked for me.

Etching bath:

• 2 gallons of distilled water.
• 2 gallons of muriatic acid. Also known as swimming pool acid. It is commonly available in most hardware stores.

Pre-plating rinse:

• 4 gallons of distilled water.

Electroplating bath:

• 4 gallons of distilled water.
• 8 oz (by weight) of zinc oxide powder. This works out to 1 oz - 2 oz per gallon. This is the stuff that lifeguards put on their noses to prevent sunburns (only they use a lotion form). This is a white powder. I purchased 1 pound for USD $16.86 delivered on ebay.
• 48 oz (by weight) of sodium hydroxide (NaoH). This works out to 10 oz - 12 oz per gallon. This is also known as as lye. NASTY STUFF! Do not let it touch any part of your skin. It will burn instantly. If you get it in your eyes you will be blind. Be very, very, very, very careful with this stuff. Always add this to your water. Never add water to the dry powder sitting at the bottom of the bucket. A chemical reaction will violently boil the water instantly. Not good. NASTY STUFF! I purchased 5 pounds for USD $23.40 delivered on ebay.
• I also added a bottle of Niacin (purchased from the Wal Mart pharmacy) in an attempt to add a brightening agent to the bath. It didn't seem to work for me. Maybe I didn't use enough. It is certainly NOT a critical component in the bath, but I wanted to list it here for full disclosure.
• I also added most of a small bottle of Molasses (purchased from the grocery store) in an attempt to add a brightening agent to the bath. I think it helped some, but it certainly wasn't a night-and-day difference. If I had to create my bath again, I'd add it in again. I don't believe the quantity is critical, but it is used up as the bath is used and will have to be added.
• Thanks to Jason Telford for sending me the following information. Jason has much more knowledge in this area than I do. I haven't tried saccharin yet.

  I wrote up a lab for our undergraduates to do nickel plating - which works very well - and what I learned as I wrote it up was that saccharin is often used as a brightener (at least in nickel baths). Niacin and saccharin are both coordinating ligands (makes a bond to the metal), but saccharin is much weaker, so it might be a better transfer agent. I think it also affects how the metal is deposited - makes it more columnar deposition. You might give it a try. I used Sweet n' Low - two or three packs per liter of solution.

Final rinse:

• 4 gallons of distilled water.

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