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Safety cold bronzing system
at room temperature

INDUBRYN KB produces a black coating on any kind of non-stainless steel easily and safely at room temperature.

Followed by a water displacing agent, the cold bronzing process offers an integrated, stainless coating without dimensional changes.

Safety cold bronzing system at room temperature

Cold Bronzing products

INDUBRYN® AR 85 for pre-treatment


INDUBRYN® KB 10 for bronzing


INDUBRYN®WV 12 for rust-proofing



INDUBRYN® KB Safety Cold Bronzing System vs. Hot Bronzing


Hot Bronzing

Energy costs

none (or only low with
hot preparation)
very high
Safety Application at room temperature,
not corrosive, not flammable,
easy to thin with water,
selenium concentration 0,9%
= low toxicity danger class
Application only at
high temperatures,
difficult to mix with water,
highly corrosive!
considerable amount of steam
Handling no warm-up time,
ready for operation immediately
Heating time: 2-6 hours,
difficult to rinse,
hot rinsing necessary in most cases
Operating equipment Polypropylene or polyethylene chambers, no heating,
filtration necessary in large chambers,
very low operating costs
Extraction and heating necessary
Controlling the solution Simple colour-change control, titration Can only be estimated at
boiling temperature
What can be bronzed? All kinds of non-stainless
steel (including cast iron)
A brown coating forms with
certain types of cast iron,
desiccating the bronzing salts
on the surface is also
difficult to avoid
Dimensional changes none none
Production facility No special workshop required,
chambers can easily be moved
Special workshop required,
fixed facility

Do you have any questions?

Our team of experts is happy to assist you by phone or email. Further information to our products, safety data sheets etc. can also be found in the download area.

+49 7331 9878-0

Tips and Application information for the
INDUBRYN KB Safety Cold Bronzing system


As with other chemical treatments of metal surfaces, preparation and aftercare - in other words all the procedures applied during these processes - have to be precisely coordinated with the main process. For the purposes of this, the correct sizes of containers must be used which not only permit the technical application data of the preparation and after-treatment products to be complied with exactly, but also allow the intermediate rinsing procedures to be carried out efficiently. The number of procedures and the kind of products used depends on the particular tasks. In most cases however, the following processes are carried out:

1. Degreasing
Using hot degreasing agents or other degreasing mediums.

2. Cold rinsing
Immerse the parts in clean, clear water (flowing) to remove all residues from the preparation processes to avoid contamination of subsequent baths (operating life and effectiveness).

3. Activation
Rigid steel should be prepared in a special acidic medium or activating concentrate (INDUBRYN® AR 85). This is only necessary depending on the kind of metal or if the parts have rust, scales, roller coatings or other impurities not removed during the degreasing process which would make a good bronzing process more difficult.

4. Cold rinsing
Immerse the parts in clean, clear water (flowing) to remove the alkalis without leaving any residues in order to avoid contamination of subsequent baths (operating life and effectiveness).
Time: several minutes

5. Cold bronzing
Immerse in INDUBRYN® KB 10 at room temperature
Time: 2-30 minutes, the length of immersion depends on the condition of the material, pre-treatment and the bath solution.

6. Cold rinsing
Immerse in clean, clear (flowing) water so that the bronzing chemicals are removed without leaving any residues and so that the surface is neutralised.
Time: approx. 1 minute

7. Rust-proofing
Immerse in cold, water-deplacing oil (INDUBRYN® WV 12). When working with complicated shapes, you must ensure that all water is able to be drained, from hollows for example. The parts may have to be turned or swivelled in order to do this.
Time: from 5 minutes

You only have to increase the immersion time in order to strengthen the coating (decorative effect).

8. Drying
Drain off the corrosion prevention medium and leave to dry.

If a jet unit is available, all cold bronzing preparation steps may be omitted (items 1-4).

Preparation and usage
INDUBRYN® KB 10 is only suitable for use in PP and PE containers.
With larger bronzing systems, the procedure should be carried out with distilled water. Clean, clear water is sufficient for smaller systems.INDUBRYN® KB 10 should be prepared as a 25% solution. Weaker solutions lead to slow and unsatisfactory results. Solutions which are too strong lead to an unwanted powder coating. TheINDUBRYN® KB 10 product must not be heated.

Storage and maintenance
If the cold bronzing medium in the polypropylene or polyethylene container is not currently in use, put a lid on it. Filtration will then be necessary if the medium becomes thick (operating life and effectiveness). In addition, if the bath is well maintained, it may be topped up as and when required and no complication bath changes are necessary. A filtration pump which maintains the cold bronzing medium is recommended for larger systems.

Bronzing performance
Parts that have already been bronzed in the past may be re-bronzed as long as they have been carefully degreased in advance.

Durability may be reduced with well-polished surfaces. These surfaces can be remedied by cleaning the metal before bronzing. Depending on the composition of the steel, this may result in a less glossy surface.

1kg of concentrate is sufficient for 4m2 of bronzing coating, but this number can be increased through 1) active bath maintenance (filtration), 2) complete degreasing or 3) activation (if necessary). Activation treatment as described helps increase the life of the bronzing coating, but also reduces the coating's glossy effect at the same time. The glossy effect also depends on the hardness of the material.

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