Cold colouring or hot burnishing? - a comparison
|
DEWE cold colouring process |
DEWE hot burnishing |
Characteristics |
black conversion coating formed on the basis of various heavy metal deposits |
chemical oxidation process under DIN 50938. A black mixed iron oxide (Fe3O4) formed on surface |
Quality of the colouring |
|
|
Corrosion protection |
comparatively low |
comparatively higher |
Treatment equipment |
low expenditure |
higher expenditure due to heated container, exhaust air unit control and regulating technology |
Energy use |
none |
higher energy expenditure |
Availability |
immediately operational |
2-3 hr. heating up time |
Treatment duration |
approx. 30 - 45 min. |
45 - 60 min. |
Chemicals expanditure |
comparatively high |
comparatively low |
Life |
shorter, limited extent of durability and regenerability |
unlimited with regeneration |
Summary
- Quality comparison
Small parts very suitable for cold colouring.
Larger parts tend to spot formation in cold colouring and are less suitable.
- Economic comparison
The cold colouring bath has only a limited life, depending on the surface. The coating cost per sqare metre m are as a rule over 50% higher for cold colouring as for hot burnishing.
Conclusion
- Small pieces and smaller quantities as well as cast materials are very suitable for cold colouring, especially if these parts must be burnished externally.
- This also applies to hot burnishers, which only sporadically use their burnishing equipment, in order to be able to colour small parts at short notice.
Aids to decision-making
Our service. Your decision.
Free sample-treatment judgement of the quality at our premises. Also information and advice on alternative solutions.