Trouble Shooting Guide

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Blackfast trouble shooting guide

Based in Surrey, Blackfast have developed a process that is a very easy to maintain and control. When things don’t go right, this handy trouble shooting guide is designed to help.
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Problem: The blacked finish is uneven black, specked or patchy

A patchy finish is most often caused by the component not being clean enough when it enters the blacking tank
  • Check degreaser for oil contamination.
  • Check the components are being left long enough in the degreaser.
  • Ensure the degreaser is being used at correct working temperature.
  • Ensure the degreaser is up to strength. Poor rinsing can lead to a component not being clean enough to black successfully.
  •  If static rinse tanks are in use, change rinse water more often and consider using running water rinses.
  • If running water rinses are in use consider increasing flow rate.
  • Consider introducing air agitation into rinse tanks to aid rinsing.
If the above suggestions do not solve the problem consider using a stronger degreaser, for example Blackfast 626 hot powder degreaser. The above suggestions apply equally to the use of a hot degreaser.
If the patchy finish is on parts of a component that has scale or rust on the surface replace Blackfast 551 conditioner with Blackfast 513 acid pickle

Problem: The black finish is wiping off

  • This is generally caused by the component not being clean enough follow the advice in section one (above) for things to check and possible solutions.

Problem: The black finish is soft and smutty

The component is being over blacked in the Blackfast 181 blacking tank.
  • Reduce the length of time components are spending in the blacking tank.
  • Check the 181 blacking solution is not too strong.

Problem: Black colour is not obtained – the colour achieved is copper brown

  • Blacking solution is too weak; test and top up to correct strength.

Problem: Black colour is not obtained – the colour achieved is grey/black

  • Blacking solution is too cold; check temperature is maintained at least at 18oC.

Problem: Black colour is not obtained – the colour achieved is pale blue

  • Blacking solution is too weak; test and top up to correct strength.
  • Blacking solution is too cold; check temperature is maintained at least at 18oC.

Problem: Black colour is not obtained – the colour achieved is dark blue

  • Blacking solution is too strong; test and reduce to correct level by the addition of water.

Problem: The Blackfast reaction is too slow

  • Blacking solution is too weak; test and top up to correct strength.
  • Blacking solution is too cold; check temperature is maintained at least at 18oC.

Problem: The Blackfast reaction is too fast

  • Blacking solution is too strong; test and reduce to correct level by the addition of water.
  • Ensure the blacking solution is not above the recommended working temperature of 25oC.

Problem: The finished components are showing signs of corrosion when removed from the oil

  • Check the components have not flash rusted because they have been left too long in the water rinses or suspended in the air too long.

Problem: Rust stains in blind holes and threaded areas

  • Water has not been removed from these blind holes and threaded areas blow holes out before oiling.
  • If this type of rusting occurs with smutting, (some of the black finish rubbing off), the component has been left too long in the 181 blacking tank. Water and oil have been absorbed into the smut and have dried out. Reduce the time the component spends in the blacking tank.

Problem: The finished components are showing signs of corrosion when in stores/assembly area

  • Ensure the water rinses are clean and that the water is pH neutral.
  • Ensure that the components are given sufficient time for the water in the emulsion oil (Blackfast 925 or 933) or the solvent, (in the case of Blackfast 833), to evaporate before the component is handled or packed.
  • If an acid pickle is being used ensure that the water rinses are thorough and effective. In the case of cast iron parts ensure that only a phosphoric acid based pickle is used.
  • Do not wipe oil off the components
  • If the components are heated in hot water prior to emersion in Blackfast 833 dewatering oil ensure that oxidation has not occurred.
  • Drain accumulated water from the Blackfast 833 tank.
  • Check that water droplets are not present on the metal surface when component is removed from the Blackfast 833 tank. Replace oil.
  • If using Blackfast 925 or 933 dewatering preparation ensure that the solution running at least 16% strength and not less.

Contact Blackfast for high quality blacking products in the Midlands and across the UK

Telephone: 020 8339 7370 Email: sales@blackfast.com
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