I use this patina method often and I feel the results are very consistent and easy to achieve so I’m happy to share it with those interested in trying it out for themselves.
There are a few different variations of this general method but since I’ve been able to replicate the results consistently, this is the one I stick to. I do believe there is room for experimentation however, so feel free to make changes as you see fit. This patina will work on iron and steel (not stainless steel) but make sure the metal is not painted, treated or coated with anything that is meant to protect it from rusting or corrosion, or has any other surface coloring or application before you begin.
This patina should be a dark brown to black when done correctly. The patina is fairly fragile as it is only on the surface of the item so it is probably not best suited for items that will see heavy use or abuse.
Safety: Make sure to always wear a mask or respirator as well as eye and skin protection when working with heat and chemicals. It is best to work in a well ventilated area and take all precautions necessary before and after working with potentially hazardous materials. Do your research on any material, chemical, or substance you will use before proceeding.
What you will need
Acetone – or any cleaning solution that will remove dirt, oil, and grease
Hydrogen Peroxide – I use 3% most of the time with good results but a higher concentration is fine too
Coarse salt – I don’t know if this is necessary and regular salt may work fine but it’s all I’ve ever used so…
Clean your items very well of any paint, coating, bluing, corrosion, dirt, grease, or anything else that might prevent a smooth process. You might want to give the item a light sanding to make sure surface is completely clean.
Step 1 – Heating solution
Measure approximately one cup (or enough to cover your items) of Hydrogen Peroxide and 1/2 teaspoon of coarse salt and mix together in pot over low heat. Stir until salt is dissolved and liquid is almost at a simmer.
Carefully place items in the solution using tongs or similar tool to avoid getting the liquid on your fingers or splashing by dropping them in. You will see the solution start to fizz immediately.
Let the solution run it’s coarse. It should go for about 2-5 minutes and then it will die down.
As it runs it’s course, the water will turn reddish brown.
Remove the items from the solution, rinse them with tap water, dry them and proceed to card the loose rust from the surface with the brush. You don’t have to remove all the rust, once it stops coming off easily, stop and rinse with water again.
The number of times you need to repeat these steps depends on how quickly the rust covers the items completely.
I average between 4-6 times but your results may vary. Flip an item such as a tsuba for each bath so both sides get equal exposure. Make sure to dump spent solution, rinse pot and start with a fresh mix for each bath.
Brush off loose rust and rinse.
Step 6 – Boil in tea
Place a couple of tea bags in some clean boiling water
Allow the water to turn dark.
Place items in the pot and let boil for at least 45 minutes or longer, occasionally flipping items such as a tsuba.
After items are done they should appear dark brown to black.
Remove them from the boiling tea and quickly rinse under hot tap water, thoroughly pat dry and immediately apply a thin layer of a micro-crystalline wax such as Renwax. Follow product instructions. An alternative to wax would be rubbing in mineral oil or coating with clear lacquer.
Re-apply wax as needed as the item is used to maintain a protective barrier. If needed, you can sand down and do the whole process over again until satisfactory.
As an additional step to stop the rusting process, you can soak the pieces in paste of sodium bicarbonate and water for 45 minutes after they are removed from the tea bath.
©All pictures and content property of Cottontail Customs® 2014