Lacquered metal
Brass, copper or steel under a clear film applied to stop it tarnishing. Every metal polish sold for the metal underneath attacks the film instead.
In detail
A great deal of decorative brass, copper and steel leaves the factory under a clear lacquer, applied precisely so the metal does not tarnish and does not need polishing. That intent is defeated by the most obvious form of care: a metal polish is a fine abrasive with a chemical assist, and applied to a lacquered surface it abrades and clouds the coating rather than touching the metal. The result is a piece that looks worse after polishing and cannot be improved by more of it. Identifying the finish is therefore the first step rather than a refinement, and the conservation guidance for copper alloys makes the same point in stronger terms: treatment depends on whether the surface is bare, deliberately patinated, or lacquered, and a method appropriate to one destroys another. A lacquered surface is cleaned as a coating — warm water, a neutral detergent, a soft cloth, dried immediately. Where a lacquer has failed in patches, the metal beneath tarnishes only where it is exposed, producing a blotchy appearance that no cleaning corrects; the honest options are to strip and re-lacquer, or to strip and accept a piece that will need polishing from then on.
Properties
Sensitivity
- Acids
- Recorded
- Alkalis
- Recorded
- Chlorine bleach
- Not known
- Heat
- Recorded
- Abrasion
- Recorded
- Porous
- Not applicable
“Not known” means CleaningHQ has not established this, not that the material is unaffected.
Why
- Lacquered metal is explained by Polishing removes metal
- Lacquered metal is explained by Solvents and polymers
- Lacquered metal is explained by Coating thickness
Related
- Lacquered metal is commonly affected by Tarnish
- Lacquered metal is commonly affected by Grease
- Lacquered metal is commonly affected by Fingerprints
Hacks and claims involving this
- Lemon and salt to clean copper Established practitioner practice
Sources for this page
Sources
Technical Procedures: Cleaning of Copper Alloy Objects
United States General Services Administration (GSA), Historic Preservation · Reference work
Relied on for: That treatment of copper alloys depends on whether the surface is bare, lacquered or deliberately patinated, and that a method appropriate to one is damaging to another. (states this directly)
Verification: a person has read the passage relied on.
Read on — Section 2.02, cleaning of copper alloy objects, and 2.03, application of clear coat. Supports the claim as stated.
Caring for your collections: Silver and plate
The Institute of Conservation (Icon) · Trade or professional body
Relied on for: That polishing removes material and that its frequency should be minimised on finished and historic pieces. (cleaninghq's interpretation of what it says)
Verification: a person has read the passage relied on.
Read on — The tarnish, cleaning, and methods-to-avoid sections. Supports the claim as stated.
Last reviewed by a person on .