Marking blue, layout stain or Prussian blue is a dye used in metalworking to aid in marking out rough parts for further machining. It is sometimes called Dykem (after a popular brand). It is used to stain or paint a metal object with a very thin layer of dye that can be scratched off using a scriber or other sharp instrument to reveal a bright, yet very narrow line in the metal underneath. The advantages are that any existing scratches are covered with the dye and the new lines have a contrasting background.
Marking blue is made by mixing methylated spirits with shellac and gentian violet. This is not to be confused with the non-drying engineer's blue, made by mixing Prussian blue with oil or grease. Despite this, it is sometimes called engineer's blue, which can cause confusion.
Video Marking blue
Alternatives
A felt tip marker can be used as they are convenient and tend not to dry up as quickly; marking blue in the form of dye or ink has a tendency to dry in the containers and become unusable quickly. On rough structures, such as castings or forgings, whitewash or a mixture of chalk and water can be used. A solution of copper sulfate, distilled water, and a few drops of sulfuric acid can be used on machined surfaces. This thin copper coating is more resistant to rough handling and the action of cutting fluid.
Maps Marking blue
See also
- Engineer's blue
References
Source of article : Wikipedia
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