How to Make an Affordable Rust Patina Solution for Metal Art

One of our local sheet metal suppliers sells an effective rust patina solution for around $50 for a one-gallon jug. It works well, but it’s not very affordable. It produces a smooth, consistent surface rust that is perfect for the metal art that we produce.

We’ve come up with a product that produces the same (or better) results and costs around 90% less than the store brand we just mentioned.

Keep in mind that this does not produce the dark bubbly rust that deeply penetrates metal, like most of the homemade solutions that I have come across online. Our solution produces consistent coppery rust finish with softly contrasting streaks and splotches. And it only costs about $5 per gallon. Nice.

Note: We’ve only used our solution on cold rolled mild steel, and it works beautifully.

IMPORTANT

  • When working with acid, always wear chemical resistant gloves, wraparound eye protection, face shield, long sleeves (preferably a smock or lab coat), and a respirator mask.
  • Always add acid to water (never water to acid).
  • Fumes can be dangerous, so always mix chemicals outdoors, or in a very wellventilated area.
  • Acid can corrode objects and surfaces, so keep this in mind when choosing a location to work with these chemicals.

Cold Nose Designs(TM) Rusting Solution Recipe
(makes approximately one gallon)

 

Ingredients

12 ½ cups - Water (tap water will do just fine)

3 cups – Muriatic Acid (14% solution)

4 ½ TBSP – Dry Copper Sulfate

2 TBSP – Sulfamic Acid Crystals

 

Instructions for mixing

Use a heavy-duty one-gallon container with a tight-fitting lid, and make sure it is suitable for containing chemicals. Use a funnel to avoid spilling the ingredients.

  1. Add water.
  2. Add dry copper sulfate.
  3. Add sulfamic acid crystals.
  4. Add muriatic acid.
  5. Close the container tightly.

How to apply (the surface must be very clean for good results!)

  • Make sure the steel’s edges are deburred, and the surface is prepared. We use a 4 ½inch angle grinder with a 40-grit flap disk to lightly grind the surface of the metal to remove all scale and oils.
  • Wash the surface with detergent (we find that Dawn brand works best) and water to using a washing brush to remove any remaining dust and oils. Then rinse with water and allow it to dry completely.
  • Applu an even coat of rusting solution using a brush or spray bottle. We use a chemicalresistant 32-ounce plastic spray bottle on the mist setting to apply.
  • The surface will initially turn a reddishcopper color with some green areas right after spraying.
  • To transform the surface to a matterust color, allow the solution to dry and keep the metal piece in a humid location. We recommend using a spray bottle to completely mist the surface with water periodically. This will accelerate the rusting process.
  • The longer the item is left in humidity or receives periodic misting, the darker and more even the rust color will become.
  • When you are satisfied with the finish, you can apply a base solution to arrest the rusting process. We use a onequart spray bottle filled with water and one tablespoon of household baking soda. After applying the base solution, let stand for around 30 seconds and rinse the piece thoroughly with water. Note: It’s best not to allow the base solution to dry before rinsing.
  • Your piece is now ready to finish depending on your application. We use a protective clear coat for our decorative pieces.

Where to Buy Chemicals

  • Muriatic Acid (14% solution) – Available at Home Depot as a Pool Chemical for ~$8/ga

  • Dry Copper Sulfate – Available on Amazon for ~$23 for 5 lbs.

  • Sulfamic Acid Crystals – Available on Amazon for ~$27 for 2 lbs.

Ideas? Questions? We're here for you.