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LEAD CORROSION

Restoring at the frontier of our knowledge

Lead corrosion

•Why is it a problem?•What is lead corrosion?• How can we avoid lead corrosion?• How can we repair the damage?

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Hamburg, 1588

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Alkmaar, 1645

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Alkmaar, 1645

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Alkmaar 1645

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Alkmaar 1645

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Why is it a problem?

• Loss of historic material• Loss of information• Loss of sound quality•Demo?

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What is corrosion?• Corrosion is an electro-chemical

reaction in which one material oxidizes and another reduces.

• Electro-chemical• Oxidation/Reduction• Two directions

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Balance

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Pourbaix diagram PbS

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Facts

Replacement pipefeet (mm)Year/division 1986 2004 2014RP 1045 40 865

HM 2537 1907 13989

BW 6825 0 16776

Ped 1321 157 3074

total 11728 2104 34704

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Why Alkmaar?

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Why Alkmaar?• Carbon dioxide from the gas

heating?• Almost no acetic acid, nor formic

acid• CH4 + 2O2 ®  CO2 + 2H2O• CO2 + H2O ® H2CO3

• COLLAPSE

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How to avoid lead corrosion?

• Influence the balance (remove an ingredient)–water– oxygen– acid

• Sealing • Rinsing

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Rinsing

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How can we repair the damage?

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Replacing corroded metal

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Bovenwerk Prestant 8

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Bovenwerk Prestant 8

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Bovenwerk Prestant 8

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