Otto's Original - Quality products since 1901


Pickling products and weld cleaning agents

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Packaging units:
Plastic canisters (for liquid varieties) or cans (for ZUNDEX paste) with 500 or 1000 ml; larger containers on request.
Application area: liquid, ready to use for iron and steel
Application: Treatment of metal surfaces after exposure to heat
ZUNDEX products are used for the treatment of metal surfaces after heat exposure. In many machining processes that require heat treatment, changes in the material surface inevitably occur. These are mainly oxidation phenomena which lead to an undesired colour change. Welders, for example, are familiar with the problem of tarnishing, which can hardly be avoided in their work. Furthermore, the surface of saw blades and similar high-speed processing tools is often discoloured in the same way, i.e. by the effect of high temperature. The well-known “burn marks” then appear. ZUNDEX pickling products provide a quick chemical remedy in such cases. Their active ingredients react intensively with all metal oxides, dissolving them and making them removable. Furthermore, flux residues, slags and other impurities can be easily removed by cleaning with ZUNDEX.

The following ZUNDEX products are available for the various fields of application and working methods:

  • ZUNDEX “NE”, Cat. No. 360 liquid, ready to use for copper, all Cu alloys and nickel
  • ZUNDEX “FE”, Cat. No. 361 liquid, ready to use for iron and steel
  • ZUNDEX “VA”, Cat. No. 364 liquid, ready to use for stainless and acid-resistant stainless steels of all kinds

ZUNDEX pickling products are free of hydrochloric, sulphuric and nitric acid. They do not contain hydrofluoric acid or any hydrofluoric acid salts. Special wetting agent additives cause a fast and uniform reaction on the surfaces to be treated. When using ZUNDEX products, a ” slightly more sluggish” reaction is sometimes observed than when using pickling mixtures of more aggressive and therefore often highly toxic mineral acids. However, this apparent disadvantage is at least offset by the advantages of the milder ZUNDEX mordants, which do not emit free chlorine or nitrous gases. However, since even ZUNDEX products are not free of corrosive substances, it is always recommended for safety reasons to wear gloves and protective goggles when using these pickling agents.

Processing instructions:
If the surfaces to be treated are not only discoloured by oxidation but also have other impurities (e.g. only partially burnt oil or resin residues, coarse welding slag, heavy dirt), these must first be removed mechanically. Subsequently, the corresponding ZUNDEX type is applied by brush or in a similar way. ZUNDEX paste is suitable for the treatment of already mounted, sloping, vertical or “”overhead”” surfaces. If the oxide layers have been chemically transformed and are removable, they can be removed by brushing or wiping. In case of particularly heavy contamination, repeat the treatment with ZUNDEX. Each time ZUNDEX is used, it is necessary to rinse or wash with clear water. Make sure that after the oxide solution has been completed, the resulting transformation products and all residues of ZUNDEX are removed from the treated surfaces.

Disposal instructions:
For safety-relevant data (occupational safety, handling, storage and disposal), please refer to our current safety data sheet.”


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