Mercury Mirror Decommissioning | Conservation, Restoration & Consultancy Services
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  • Mercury Amalgam Mirror Conservation

    Originally invented in the 1400s in Venice, Mercury amalgam mirrors became widely produced from the 16th Century and this method and material was in use until around 1900, being replaced by the use of silver as the reflective coating.

    During this 500 year period, the reflective finish was created by gliding glass over tinfoil flooded with a layer of liquid mercury. The mercury reacted with the tin to form a layer of tiny crystals, an alloy of mercury and tin. The voids between the crystals remain filled with a fluid phase containing approximately 0.5% tin in mercury.


    Over time, and with corrosion from humidity in the air or from damp walls, the crystals grow larger and the mercury slowly evaporates causing tiny voids to appear between the rear surface of the glass and the Amalgam.

    The fluid phase of the mercury migrates to the bottom of the mirror and the corrosion produces tin dioxide and tin monoxide which releases the liquid mercury from its solid phase.

    Whilst the usual measured values of mercury vapour in the air are far below any official toxic limit to humans, mirror frames can often contain beads of liquid mercury that can escape and need to be disposed of safely.

    We can safely remove, provide a full condition report along with treatment proposals & carry out the required conservation or decommissioning by stripping the Mercury surface and resilvering the original glass & replicating the distressed Mercury.

    - Paul Broomfield, Founder & Conservator


    Our workshops now offer a specialist decontamination and decommissioning services, in accordance with health and safety guidelines to help historic houses, museums and private collections comply with requirements to control substances hazardous to health. Removing any visible droplets and cleaning contaminated surfaces, disposing of the waste safely and sealing and lining the junctions between the glass and frame and the backboards.

    Once in our care, we can provide a full condition report along with treatment proposals. Upon approval we can carry out the required conservation or decommission by stripping the Mercury surface and resilvering the original glass with hand poured silver, creating a similar level of distressing in the reflection to echo the original mirror plate.



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