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Neutralizing steel parts after pickling

Aviation Mechanic General (AMG) practice question 6 of 31 on Cleaning and Corrosion Control. ACS element AM.I.G.K17 · difficulty: standard. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONSteel parts have been pickled to remove scale and will not be electroplated afterward. What is done to neutralize the acid remaining from the pickling solution?

  1. ARinse the parts in a Deoxylyte bath for 10 to 15 seconds
  2. BImmerse the parts in a lime bath
  3. CSuspend the parts in the electrocleaning solution
Show the answer and explanation

Correct answer: B. Immerse the parts in a lime bath

  • A — incorrect The Deoxylyte rinse is a step in alodizing aluminum that counteracts alkaline material; it is not used to neutralize pickling acid on steel.
  • B — correct The handbook states that parts not to be electroplated after pickling are immersed in a lime bath to neutralize the acid from the pickling solution.
  • C — incorrect Electrocleaning removes grease, oil, or organic matter in a hot alkaline solution with current applied; it is a separate cleaning process, not the neutralizing step after pickling.

BACKGROUND

Original surface treatments for steel parts begin with cleaning to remove dirt, oil, grease, oxides, and moisture so the final finish bonds properly. Cleaning may be mechanical (wire brush, steel wool, emery cloth, sandblasting, vapor blasting) or chemical, and chemical cleaning is preferred because it removes none of the base metal. Steel parts are pickled in muriatic (hydrochloric) or sulfuric acid to remove scale, rust, or other foreign matter, particularly before plating; sulfuric acid is cheaper but muriatic acid is more effective on certain scale. The pickling solution is kept in a stoneware tank heated by a steam coil, and parts that will not be electroplated are immersed in a lime bath to neutralize the acid.

STUDY TIP

Keep the steel-preparation sequence straight: clean, pickle, then either plate or neutralize in a lime bath.

KEY POINTS

  • Pickling removes scale and rust from steel with muriatic or sulfuric acid
  • Chemical cleaning is preferred because no base metal is removed
  • Parts not electroplated after pickling are neutralized in a lime bath

SOURCES

  • FAA-H-8083-30B ch08 "Surface Preparation"
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SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-30B Aviation Maintenance Technician Handbook – General, 14 CFR part 43 and part 65. Regulations and handbooks are revised; confirm details against the current edition.