Otto's Original - Quality products since 1901


Etching ink, black stain & bronzing agent
•Liquid medium on acid basis
•For special steel alloys and high-alloy stainless steels

Pictures may differ from the original.

Packaging units:
Packaging: refills and bottles with 1ml, 100g, 250g, 500g, 1000g
Application area: COLD BURNISHING - BLACKENING of stainless steel, corrosion protection
Application: The solution supplied ready for use is to be filled into a resistant container made of GRP, HDPE or PP.
Degreasing and inserting the parts: The parts to be blackened must be degreased before cold burnishing. In the simplest case, this can be done by washing with alcohol.
Blackening effect: Thorough degreasing of the parts is a prerequisite for uniform blackening. Depending on the material, blackening occurs quickly. If the workpiece remains too long in the blackening solution, loose oxides accumulate on the surface, which must be removed after the process (expediently with a scrubber brush, or similar). If the blackening has not become sufficient, the burnishing process can be repeated after the material has been cleaned. It has turned out that more than two burnishing passes hardly show any significant improvement. If an irregular coloration can be seen after burnishing, this is an indication of insufficient degreasing.
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Burnishing is the production of certain oxide layers by chemical means. In many cases, steel parts must be protected from corrosion and should be given an attractive black color. The dimensional stability of the parts is maintained and even highly polished surfaces retain their gloss.

NEUTRASOL post-treatment

After removing the loose oxides, which should be expediently carried out in a neutralization bath with the product NEUTRASOL – Concentrate, Cat. No. 875, the workpiece should be dried and preserved.

Neutralization bath

Regular tap water together with our NEUTRASOL can be used to prepare the bath. The pH value must be checked constantly and should not fall below pH-10, otherwise the workpieces will start to rust.
Indicator paper is used for checking.


EO post-treatment fluid, Cat. No.: 0871, is a temporarily effective, preservative metal protection for application after use of “Nigrit VA-Extra”. Corrosion is always undesirable, therefore the metal surface should be treated briefly with this fluid (thin application) after each use. The water-displacing additives reliably prevent contact between the metal surface and remaining moisture.

Other indications

No workpieces should be left in the burnishing bath or remain in it too long, otherwise the burnishing agent will decompose and become unusable. When processing on a large scale, an exhaust system is required in any case, as combustible hydrogen gas can be formed by the decomposition of metal.


Questions about our products?
We will advise you by phone 06123 / 7046-0.