Otto's Original - Quality products since 1901


Black pickling & burnishing agent
• Liquid medium on weak acid basis
• Especially for aluminum (freshly blank treated aluminum)

Pictures may differ from the original.

Packaging units:
Bottles of 100 g, 250 g and 500 g. Canister with 1,000 g. Larger containers on request.
Application area: COLD BURNISHING - BLACKENING of aluminum, acts only on blank treated areas
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 burnished 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. The areas on the aluminum that are to be blackened must be mechanically pretreated and made bright.
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Burnishing is the production of certain oxide layers (iron oxide) by chemical means. In many cases, iron parts must be protected from corrosion and should be given an attractive black color. The dimensional accuracy 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 “K”. 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 for 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.