Gregory Bender

Zinc plating

My experience setting up a functional zinc plating bath.



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DANGER! DANGER! DANGER! The information and techniques presented on this page are suitable for entertainment purposes only. The chemicals and processes described on this page can be very hazardous to your health and quality of life. The author is not an expert. If you chose to follow any of the instructions described on this page, you do so at your own risk and you accept full responsibility for your actions. DANGER! DANGER! DANGER!


It is possible to create an inexpensive, effective, and SAFE zinc plating operation suitable for the home enthusiast who wants to occasionally do small batches of zinc plating. This page describes one way of doing that.

The zinc plating I have produced would be classified as dull in color. It is not bright. It does not look like chrome, nickel, or polished stainless steel. It does not have the luster of cadmium plating. It is a basic zinc gray color whose sole purpose it to act as a sacrificial coating and protect the steel underneath. I wish I could produce bright zinc, but I have not yet figured out how to do that.

Example parts plated with zinc using my DIY zinc plating set up.
Example parts plated with zinc using my DIY zinc plating set up.

Photo courtesy of Gregory Bender.

Example parts plated with zinc using my DIY zinc plating set up.
Example parts plated with zinc using my DIY zinc plating set up.

Photo courtesy of Gregory Bender.

Example parts plated with zinc using my DIY zinc plating set up.
Example parts plated with zinc using my DIY zinc plating set up.

Photo courtesy of Gregory Bender.

Example parts plated with zinc using my DIY zinc plating set up.
Example parts plated with zinc using my DIY zinc plating set up.

Photo courtesy of Gregory Bender.


The chemicals involved in zinc plating are not the most inert known to mankind. You will be using acid and lye that can burn your skin and blind you in an instant. There will be fumes that are also nasty. With knowledge, care, and a few pieces of safety equipment, you can be safe. Don't want to learn safe practices? Don't want to follow safe practices? Don't want to buy the gear? Then don't do this. Here are some risks and safe practices to help mediate the risk. (source: FAQ file at the old Yahoo! Electroplating news group). There are certainly additional risks that are not listed here.

Getting rid of chemicals and baths

BE RESPONSIBLE!!! Please do not throw any chemicals or baths on the ground, down your drain, or in your trash. You don't want to drink it or bathe in it and neither do I. You also don't want some unwitting refuse employee getting lye all over his skin when your container breaks. Instead, take it to your local hazardous materials collection site and dispose of it there. Most communities have collection days where you can drop off things at no charge. If you have an appropriate location, you can even leave the lid off your baths and let the water evaporate...then only have the remaining residue to take to the hazardous material collection site.


Here are the materials I use:

Bath composition

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:

Pre-plating rinse:

Electroplating bath:

Electroplating bath alternative (I have not tried it, but it is supposed to produce much shinier/brighter zinc):

This bath is described in more detail on the Honda 305 forum.

Final rinse:

Plating out

Before the electroplating bath can be used on real parts, it must be plated out. This is done by plating a 2 inch × 2 inch scrap piece of steel for 12 hours.

Parts that should and should not be plated

You can certainly plate anything you want to, but some parts will lend themselves to better results than others. In my experience, it is difficult to get good results with parts that have seams or joints. This is because it is very hard to thoroughly rinse all of the acid from the etching bath prior to plating. The result is that the parts will corrode very quickly right where the joints and seams are located. The same is true for pipes, tubes, and holes. If they don't get rinsed very well, corrosion will begin there very quickly.


Always test with a few old nuts and bolts you don't care about first. It will give you a feel for the process and you won't destroy any real parts in the process.

Here are the steps involved:

  1. Parts preparation. This step is critical to success and can not be overlooked. Failure to properly prep the parts will result in poor and/or spotty zinc adhesion to the substrate. This step is time consuming and not a lot of fun, but it is necessary. Basically, you must remove all paint, grease, and dirt. Clean it until you would eat with it, then wash it with soap and water, rinse and dry. The acid in the etching bath will not etch oil or paint covered steel. Also, you do not want to contaminate your baths with nasty chunks that will then get stirred up and land on your parts, resulting in poor plating. Don't cut corners here.
  2. Hang the part. I start by hanging each part from a length of copper wire. Some parts are easier to hang that others because they have a natural location for hanging. Very small parts, however, are more difficult. But, I just bend the wire into a shape by the part can be supported and call it good. Do be careful not to drop parts into your bath. I can be a challenge to get them out...and a long magnet you don't mind getting ruined is a great help when fishing them out. I know some people have used small metal baskets to handle the tiny parts. I haven't had very good luck with this method because I get a lot of shadowing (uneven coverage) during the plating bath.
  3. Etching bath. Suspend the part from a length of copper wire in the etching bath for 1 - 4 minutes. It may bubble in the beginning and then stop bubbling after a while once the original zinc has been removed. When I get going on a small run, I hang a number of parts on the side of the bucket.
  4. Pre-plating rinse. Immediately after the etching bath, rinse the part in the pre-plating rinse at least 30 seconds. Essentially, you remove the part from the etching bath and immerse it immediately in the pre-plating rinse. If the part is oddly shaped or has compartments, be sure to move the part around in the pre-plating rinse to fully rinse the acid from the etching bath. Do not touch the piece with your gloved fingers...only handle it by the copper wire. If you touch it, it gets a trip back to the etching bath. When I get going on a small run, I hang a number of parts on the side of the bucket.
  5. Plating bath. Immediately after the pre-plating rinse, immerse the part in your plating bath. Hook the copper wire over the copper pipe that is sitting across the top of your bucket.
    • The negative wire from your power supply will be connected to the copper pipe.
    • The positive wire from your power supply will be connected to the zinc anode (which is also at least partially immersed in the plating bath).
    • The zinc anode and your suspended part must not make direct contact.
    • Turn on your power supply and you will start to see bubbles come up to the surface as the zinc ions are being transferred from the zinc anode to your part (the cathode).
    • There are specific amperage's and durations that can be calculated for the surface area to be plated on each part. Honestly, I've never bothered to figure this out. I do know that the amount of time (unless left plating for way too short or way too long) has not made an appreciable difference in the quality of zinc coating I've gotten.
    • About half way through the plating, I flip the part around 180° and hang it on the other side of the copper pipe. In doing so, I'm attempting to get even coverage on the part and prevent shadowing where one side is plated much more thickly than the other side.
    • How long do I plate? Well, it all depends on how large the piece is. Small pieces may only require 30 seconds. Large pieces as long as several minutes. Don't be afraid to pull the part out of the bath and have a look. You can always just drop it back in. After just a little while, you'll get a feel for how long it takes to plate the pieces you are doing.
    • With large pieces, I do them one at a time. But, if I have numerous small pieces (small nuts and bolts, etc), then I'll do several of them at once.
    • Before I begin and every few minutes thereafter I stir the chemicals in my plating bath. Perhaps this is normal or perhaps I used too many chemicals or not the correct chemicals or whatever, but my zinc oxide and molasses tend to settle at the bottom. So, I stir them up and keep my bath nice and cloudy.
  6. Final rinse. Immediately after the plating bath, immerse the part in the final rinse for 30 seconds. The purpose of this rinse is simply to dilute the chemicals from the plating bath.
  7. Dry. Towel dry each piece immediately after the final rinse. Don't be surprised if your towel gets a little gray from the extra zinc that didn't adhere fully. But, you should be left with a nicely plated piece. Set the piece aside to fully air dry. I like to place each piece - not touching - on a long piece of plywood. The wood absorbs any moisture and the separation of pieces prevents spot rusting. You could also just hang them up all around your garage, etc.

The good news is that if you make a mistake, you can just start right over again with the etching bath and run the part through again. The nice thing about zinc plating is that it is pretty forgiving.