Patina Formulas for
Brass, Bronze and Copper
 The Science Company has collected these recipes from a variety of sources through the years. The formulas have not been personally tested so there is no guarantee that they will work. We suggest they be employed on a "trial and error" basis first so their effectiveness can be judged by the user. Cold Process = Cold solution, Cold metal, Cold rinse water.
Hot Process = Hot solution, Hot metal, Hot rinse water.
INDEX
Select coloring effect and learn how to create it with the formula.
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1. Light to Dark Brown
Ingredients
Process
Hot or cold process. (Red to reddish brown has also been reported using this recipe.)
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2. Brown to Black
Ingredients
Process
Hot or cold process. Use fresh solution each time.
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3. Blackish Brown
Ingredients
Process
Hot or cold process. Mix in the order given.
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4. Florentine Brown
Ingredients
Process
Hot or cold process. This old Italian formula produces a rich brown patina.
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5. Antique Green
Ingredients
Process
Hot process. Solution hot (180 to 190°F), metal hot (200°F), cold wash water applied after metal has cooled to around 100°F. Wash solution over metal surface, let dry, then wash piece in cool water. Repeat until color develops.
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6. Basic Green
Ingredients
Process
Hot process, semi-transparent patina. Heat metal and apply a fresh mixture for each coloring.
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7. Blue Green
Ingredients
Process
Hot process. Solution hot (180 to 190°F), metal hot (200°F), cold wash water applied after metal has cooled to around 100°F. Wash solution over metal surface, let dry, then wash piece in cool water. Repeat until color develops. For Yellow Green, dip in dilute nitric acid, then wash and dry.
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8. Cold Process Green
Ingredients
Process
A cold process, opaque patina. Frog green results after several applications, 1/2 hour intervals. Color is not satisfactory alone. Combines well with most brown and black cold process patinas.
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9. Light Green
Ingredients
Process
Hot process. Solution and metal hot (140 to 160°F).
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10. Green
Ingredients
Process
A cold process that is said to work well on brass.
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11. Green - Blue (Flemish)
Ingredients
Process
Temperature at 170 to 190°F, a hot process especially for brass.
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12. Purple to Light Green
Ingredients
Process
Parts by weight. Early stages of this recipe produce purple. Additional applications and chemical action turn the metal light green.
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13. Transparent Blue
Ingredients
Process
A transparent, dip process patina. A preservative such as paste wax or polyurethane is necessary. May produce a grey blue when tap water is used.
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14. Blue
Ingredients
Process
Brush onto surface.
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15. Straw Yellow
Ingredients
Process
Heat metal and apply hot liquid.
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16. Golden Yellow
Ingredients
Process
Heat solution to a boil. Dip.
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17. Deep Rust Red
Ingredients
Process
Brush to surface for color. Then dip into diluted (1 acid:8 water) Nitric acid for 1/2 hour, remove, wash and dry.
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18. Purple
Ingredients
Process
Parts by weight. Brush to surface.
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19. Antique White
Ingredients
Process
Heat metal and apply liquid. Variations of this formula add a pinch of Sulfurated Potash, Ferric Nitrate, or Cupric Nitrate for a slight coloring effect.
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Formulas Suggested for Specific Metals.
20. Red - semi-matt (for Copper & Copper Plate)
Ingredients
Process
Boil immersion (A) 15 min.
Boil immersion (A)+(B) 10 min.
Immerse in boiling cupric sulfate solution about 15 min. or until color well developed.
Remove to hot water while ammonium chloride is added to the cupric sulfate solution. Then immerse about 10 min. Remove and wash in hot water. Dry and finish.
Important note: In general, chemically induced finishes are unsuitable for use on articles to be used with food.
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21. Dull Pink (for Copper & Copper Plate)
Ingredients
Process
Hot immersion - 5 min.
Immerse in hot solution (140-158°F, 60-70°C) which etches surface. Remove after 5 min., wash in warm water and air dry. Wax finish.
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22. Red-Purple Satin (For Cast Bronze and Brass)
Ingredients
Process
Boiling immersion (10 to 30 min.)
Immerse in boiling solution. A reddish orange color begins after 2-3 min. and deepens with continued immersion. When a reddish-purple color is attained from 10 to 30 min. remove and wash well in hot water. Dry and wax finish if choose.
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23. Orange-Brown (For Cast Bronze and Brass)
Ingredients
Process
Heat immersion (15 min)
Immerse in hot solution (176°F, 80°C). Color develops gradually and remove after 15 min. Wash and dry wax finish if choose.
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24. Black - semi-gloss (For Cast Bronze and Brass)
Ingredients
Process
Hot immersion (20 min.)
Immerse in hot solution (140-158°F, 60-70°C). In one minute the surface is colored blue-purple. This recedes to a brown color, then changing to gray. After 20 min., remove, washing in hot water and dry in air. Handle as little as possible.
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25. Blue Green (For Cast Bronze and Brass)
Ingredients
Process
Applied paste - several days.
Using a mortar and pestle, grind ingredients to a creamy paste with the acetic acid. Apply paste to object with a soft brush giving a thick coating. Dry for one day. Wash dry residue away under cold water using a soft brush. Apply a thin layer of paste with a soft cloth and dry again for one day. Wash off residue again. Apply thin layer and dry until good variegated patina is achieved. When treatment completed, dry thoroughly. May be waxed.
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26. Golden Yellow (For Cast Bronze and Brass)
Ingredients
Process
Boiling immersion (15 min.)
Immerse object in boiling solution. A dark brown layer forms on surface after 1-2 min. Remove object and bristle-brush under hot water. Re-immerse and repeat process after 2 min. if necessary. Immerse again to approximately 15 min. remove and wash thoroughly in hot water using a bristle brush if necessary. Dry and wax finish of choice.
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27. Blue Green - semi-matt (For Cast Bronze and Brass)
Ingredients
Process
Applied liquid.
With mortar and pestle, grind ingredients with a little water. Then add to remaining water. Dab and wipe on sparingly with soft cloth, to leave an evenly moist surface. Allow to dry in air. Repeat procedure once a day for several days as color develops. Dry for several days during which time the patina develops further. When there is no more surface change, wax to finish.
The most important part is to let it dry throughly between applications and up to two weeks before waxing.
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28. Brown - Greenish Yellow (For Cast Bronze and Brass)
Ingredients
Process
Immerse in hot solution (140-158°F, 60-70°C) to cause etching of the surface and gradual darkening. After 5 minutes remove and wash in warm water. Allow to air dry. When dry, wax finish.
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29. Reddish Brown (For Cast Bronze and Brass)
Ingredients
Process
Boiling immersion (10-15 min)
The color will develop after 10 - 15 min. Remove and wash in hot water. Dry thoroughly, wax finish.
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30. Black (For Cast Bronze and Brass)
Ingredients
Process
Heat immersion - 1 minute.
When article is immersed in hot solution (120-140°F, 50-60°C) a succession of colors is produced. It changes to a purplish color after about 45 seconds. The color darkens quickly and the article is removed after about 1 minute. Wash thoroughly in hot water and air dry, wax finish.
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31. Variegated Gold-Brown (For Cast Bronze and Brass)
Ingredients
Process
Hot immersion (3-5 min.)
Immerse in hot solution (194°F, 90°C). A golden lustre develops within one minute and becomes more intense. When lustre color is fully developed in 3 - 5 minutes, remove and wash in hot water, which is also a cooling process. Finally, wash article in cold water. Dry carefully first by blotting excess moisture with absorbant tissue paper and then air dry. Wax finish when dry.
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32. Red (For Cast Bronze and Brass)
Ingredients
Process
Heat metal and apply hot liquid
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Feedback
There are many variations of the basic steps outlined above. Let us know what you tested and how your experiment turned out. We'd be delighted to hear from you!
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