Needlegun scaler

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A U.S. Navy Seaman uses a needle-gun to remove old paint and corrosion aboard USS Kitty Hawk.[1]
An able seaman uses a needlegun to remove scale while refurbishing a mooring winch.

A needlegun scaler, needle scaler or needle-gun is a tool used to remove rust, mill scale, and old paint from metal surfaces.[2] The tool is used in metalwork applications as diverse as home repair, automotive repair and shipboard preservation.[3][4][5]

Operation and use[edit]

A needle gun has a set of very fine chisels known as needles.[3] The tool forces these needles against a work surface at variable speeds up to around 5,000 times per minute.[3][2] Different models offer choices of number of needles, operating speed, and power levels.[3] Many models use compressed air, although electrical needle-guns do exist.[3][6]

In a pneumatic unit, compressed air forces a piston forwards and backwards.[3] This movement causes the needles to move back and forth against the work surface.[3]

The needle gun has advantages over other scaling tools. Its main advantage is that the needles automatically adjust themselves to contours, making the tool a good choice for cleaning irregular surfaces.[2] A needle gun can clean an area to bare metal in seconds, and compares well to other scaling tools in terms of accuracy and precision.[3]

It is recommended that before needlegunning, a surface should be prepared by removing oil, grease, dirt, chemicals and water-soluble contaminants.[5] This can be done with solvents or with a combination of detergent and fresh water.[5] Then, the needle gun is used to remove rust, loose scale, and paint, leaving bare metal.[5] It is used most effectively by holding it at a 45° angle to the work surface.[5] It is recommended that an area no larger than six to eight inches be cleared at once.[5] Two to three passes over an area is generally sufficient to clean it.[5] Then the process is repeated until the desired area is completed.[5]

Prior to painting, it is desirable to feather any edges between metal and old paint.[5] It is also important to check the surface for oil deposited during chipping, and if necessary, clean the area with solvents.[5] Since bare metal surfaces will flash rust soon after exposure to the atmosphere, paint should be applied as soon as possible after chipping.[5] If flash rusting occurs prior to coating, further chipping, cleaning and sanding may be necessary.[5]

See also[edit]


  1. ^ U.S. Navy, 2006.
  2. ^ a b c NETC, 2003, p. 11-10.
  3. ^ a b c d e f g h Miller, 2008.
  4. ^ Park, 1984.
  5. ^ a b c d e f g h i j k l NAVSEA, 2008.
  6. ^ Nitto Kohki, 2008.

General references[edit]

  • Miller, Jason (2008-01-30). "Needle Scaler and Debris Removal". Free Online Library. Free Online Library. Retrieved 2008-04-05.
  • Naval Sea Systems Command (NAVSEA) (2008). "Chapter 7: Submarine Forces Afloat Painting and Preservation Guidelines for Non-Nuclear Spaces and Components". Contracted Ship Maintenance. Joint Fleet Maintenance Manual - Rev A Change 7. Vol. VI. United States Navy.—CHAP 7 LINK NO LONGER WORKS
  • Naval Education and Training Command (NETC) (2003) [1996]. "Chapter 11: Painting". NAVEDTRA 14343: Boatswain's Mate (PDF). Nonresident Training Manuals. Pensacola, Florida: United States Navy. Retrieved 2008-04-05.
  • "060323-N-3946H-042.jpg". Eye on the Fleet Photo Gallery. Navy NewsStand. United States Navy. 2006-03-23. Archived from the original on 12 April 2006. Retrieved 9 March 2021.
  • Park, Sharon (1984). "#13: The Repair and Thermal Upgrading of Historic Steel Windows". Preservation Briefs. Government Publishing Office. Archived from the original on 2008-04-15. Retrieved 2008-04-05.
  • Nitto Kohki (2008). "EJC-32A Electric Needle Scaler". Nitto Kohki USA. Archived from the original on 2008-06-15. Retrieved 2008-04-05.

External links[edit]