Wood's metal -

spore: profile
id: woods-metal
spore_version: 0.2
family: low-melting-metals-and-solders
name: Wood's metal
abbreviation: '-'
role: low-melting fusible alloy (about 70 °C, bismuth-lead-tin-cadmium)
category: metals
type: heavy-metals
summary: |
  Wood's metal is a eutectic alloy of bismuth, lead, tin and cadmium, named for Barnabas Wood, who patented it in 1860. Wikipedia gives its nominal composition as 50% bismuth, 26.7% lead, 13.3% tin and 10% cadmium by mass, and a melting point of approximately 70 °C (158 °F). A 1989 measurement paper on an industrial Wood alloy gives a solidification temperature of 343 K and a density of 10.15 g/cm3 on solidification, for a composition with more lead than the nominal alloy. Its room-temperature modulus of elasticity is 12.7 GPa and yield strength is 26.2 MPa, both as stated by Wikipedia. The alloy contains lead and cadmium, and the sources read say its fumes are toxic and skin contact is harmful.
best_for: Low-melting fusible links, plugs and holding fixtures, where the alloy must melt near 70 °C (Wikipedia lists fusible links in sprinkler heads and fusible plugs in boilers)
weakest_at: 'Toxicity: it contains cadmium and lead, and the sources read call its fumes toxic. Few physical data were found: no thermal conductivity, specific heat or corrosion value for the alloy was found in any source read'
identity:
  formula: Bi-Pb-Sn-Cd eutectic alloy, nominal 50% Bi, 26.7% Pb, 13.3% Sn, 10% Cd by mass
  source: wikipedia-woods-metal
  where: Lead section, composition sentence (eutectic alloy of 50% bismuth, 26.7% lead, 13.3% tin and 10% cadmium by mass)
tags:
  applications:
    - thermal-control
    - radiation-shielding
    - mechanisms
properties:
  - benchmark: melting_point
    label: Melting point of Wood's metal (eutectic composition)
    value: 70
    unit: °C
    scope: material
    conditions:
      composition: eutectic, 50% Bi, 26.7% Pb, 13.3% Sn, 10% Cd by mass (as the source gives it)
      basis: stated as approximately 70 °C (158 °F)
    method: Approximate value in the lead section of an encyclopedia article (secondary source, underlying measurement not named)
    status: ground
    source: wikipedia-woods-metal
    where: Lead section, first paragraph ("approximately 70 °C (158 °F)")
  - benchmark: melting_point
    label: Solidification temperature of an industrial Wood alloy (1989 measurement)
    value: 343
    unit: K
    scope: material
    conditions:
      composition: 'industrial Wood alloy as analysed in the paper: Bi 39.3 to 40.2, Cd and Sn 8.85 to 9.75, Pb 40.3 to 41.2 (mass %)'
      basis: solidification temperature of the alloy, printed in kelvin
    method: Value stated in the introduction of an experimental measurement paper (Kazandzhan et al., 1989, Russian; full text read)
    status: ground
    note: The composition is not the nominal 50/26.7/13.3/10 alloy. The paper notes that lead content in sources it reviewed ranges from 10 to 42 mass %. 343 K is 70 °C.
    source: kazandzhan1989
    where: Introduction, paragraph after the composition list (solidification temperature of the alloy 343 K)
  - benchmark: density
    label: Density of an industrial Wood alloy on solidification (1989 measurement)
    value: 10.15
    unit: g/cm3
    scope: material
    conditions:
      composition: same industrial alloy as the solidification temperature above (Pb 40.3 to 41.2 mass %)
      state: solid, on solidification (about 343 K)
    method: 'Density measured on samples: liquid by pycnometer, solid by hydrostatic weighing in distilled water (as described in the paper)'
    status: ground
    note: The paper gives linear equations for the liquid and solid density, not a single room-temperature value. The vendor density of 9.7 g/cm3 at 20 °C was seen only in a search result and was not read on a fetched page, so it is not recorded.
    source: kazandzhan1989
    where: Density section, text on the solid state (density rises on solidification to 10,15 g/cm3)
  - benchmark: melting_point
    label: Melting point of Cerrobend, a bismuth-base eutectic
    value: 70
    unit: °C
    scope: material
    conditions:
      basis: Cerrobend is described as a bismuth-base eutectic alloy; the Wikipedia fusible-alloy table lists Wood's metal as exactly the same as Cerrobend
    method: Value in the abstract of an ASM Alloy Digest entry for Cerrobend (the full datasheet is paywalled; the abstract was read)
    status: ground
    source: asm-cerrobend
    where: Abstract, first sentence ("melts at 158 F (70 C)")
  - benchmark: elastic_modulus
    label: Modulus of elasticity of Wood's metal at room temperature
    value: 12.7
    unit: GPa
    scope: material
    conditions:
      temperature: room temperature
      form: not stated
    method: Stated in the applications section of an encyclopedia article (underlying test not named)
    status: ground
    source: wikipedia-woods-metal
    where: Applications section, sentence on room-temperature modulus of elasticity (12.7 GPa)
  - benchmark: yield_strength
    label: Yield strength of Wood's metal at room temperature
    value: 26.2
    unit: MPa
    scope: material
    conditions:
      temperature: room temperature
      form: not stated
    method: Stated in the applications section of an encyclopedia article (underlying test not named)
    status: ground
    source: wikipedia-woods-metal
    where: Applications section, sentence on room-temperature yield strength (26.2 MPa)
corrosion: []
risks:
  hazards:
    - text: 'PubChem reports ECHA notifications for elemental cadmium (855 company reports from 40 notifications): H330 (92.2%), H341 (92.2%), H350 (92.2%), H361 (75.6%), and STOT RE 1 (92.2%), which is the H372 category. Chronic aquatic 1 is notified at 100%. Signal word Danger. Wood''s metal contains 10% cadmium, so these are hazards of its cadmium content.'
      ghs:
        - H330
        - H341
        - H350
        - H361
        - H372
        - H410
      source: pubchem-cadmium
      where: GHS Classification section, aggregated ECHA entry and Hazard Classes and Categories line
    - text: 'PubChem reports ECHA notifications for elemental lead (2,477 company reports from 93 notifications): H360 (84.4%) may damage fertility or the unborn child, H362 (44.3%) and H372 (50.5%). Wood''s metal contains 26.7% lead.'
      ghs:
        - H360
        - H362
        - H372
      source: pubchem-lead
      where: GHS Classification section, aggregated ECHA entry (CID 5352425)
    - text: 'PubChem reports ECHA notifications for elemental tin (953 company reports): 72.9% (695 of 953) say the substance does not meet GHS criteria. Where codes were given, H319 (24.2%) causes serious eye irritation and H335 (23.1%) may cause respiratory irritation. Wood''s metal contains 13.3% tin.'
      ghs:
        - H319
        - H335
      source: pubchem-tin
      where: GHS Classification section, aggregated ECHA entry (CID 5352426)
    - text: Wikipedia says Wood's metal is toxic because it contains lead and cadmium, that its fumes are toxic and that contamination of bare skin is considered harmful. It also says vapour from cadmium-containing alloys is a danger to humans.
      ghs: []
      source: wikipedia-woods-metal
      where: Toxicity section and lead section
    - text: Wikipedia says elemental bismuth has unusually low toxicity for a heavy metal.
      ghs: []
      source: wikipedia-bismuth
      where: Lead section, introduction
  failure_risks:
    - mode: Melting at low temperature
      trigger: Temperature at or above about 70 °C
      consequence: The alloy melts. The room-temperature modulus (12.7 GPa) and yield strength (26.2 MPa) do not apply above the melting point. Melting is the intended action in fusible links and plugs.
      severity: moderate
      source: wikipedia-woods-metal
      where: Lead section (melting point) and Applications section (room-temperature values)
    - mode: Release of toxic fume or dust
      trigger: Heating or melting the alloy, or handling its dust
      consequence: Wikipedia says the fumes are toxic and the dust may form flammable mixtures with air. Cadmium vapour from cadmium-containing alloys is a danger to humans.
      severity: high
      source: wikipedia-woods-metal
      where: Toxicity section
  side_effects: []
  handling:
    - text: Wikipedia says contamination of bare skin is considered harmful, and that fumes are toxic.
      source: wikipedia-woods-metal
      where: Lead section and Toxicity section
    - text: PubChem's cadmium record lists precautionary codes P260, P264, P270 and P280 among its GHS statements. The code text is not quoted here.
      source: pubchem-cadmium
      where: GHS Classification section, precautionary statement codes
  mitigations: []
uses:
  - application: thermal-control
    device: Heat-transfer medium in hot baths
    example: Wikipedia says Wood's metal can be used as a heat-transfer medium in hot baths. This is a ground laboratory use.
    source: wikipedia-woods-metal
    where: Applications section, heat-transfer bath sentence
  - application: radiation-shielding
    device: Custom-shaped apertures and blocks for medical radiation treatment
    example: Wikipedia says the alloy is used for making custom-shaped apertures and blocks in medical radiation treatment. This is a ground use, not a space use.
    source: wikipedia-woods-metal
    where: Applications section, medical radiation sentence
  - application: mechanisms
    device: Fusible link in fire-sprinkler heads, and fusible plug in boilers
    example: Wikipedia says Wood's metal is used for fusible links in commercial sprinkler heads and for fusible plugs in boilers. USGS lists bismuth fusible alloys as a triggering mechanism for fire sprinklers.
    source: wikipedia-woods-metal
    where: Applications section, sprinkler and boiler sentences; USGS bismuth Domestic Production and Use paragraph
supply:
  - subject: Bismuth
    producers:
      - country: China
        share_percent: 88
        year: 2025
      - country: Republic of Korea
        share_percent: 6.3
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals
        listed: true
    recycling: 'USGS: recycled bismuth-containing alloy scrap was estimated to compose up to 10% of U.S. bismuth apparent consumption for 2021 to 2025.'
    substitutes: []
    abundance: Bismuth minerals rarely occur in quantities to be mined as principal products; it is mostly a byproduct of lead ore processing (USGS).
    source: usgs-mcs2026-bismuth
    where: World Refinery Production table (2025 column; China 88% printed in the Events paragraph; Republic of Korea 1,000 of 16,000 t calculated by Space Mushroom); World Resources paragraph; critical list status from the USGS list page
  - subject: Cadmium
    producers:
      - country: China
        share_percent: 50
        year: 2024
      - country: Germany
        share_percent: 33
        year: 2024
    critical_lists:
      - list: USGS 2025 List of Critical Minerals
        listed: false
    recycling: 'USGS: secondary cadmium is mainly recovered from spent consumer and industrial NiCd batteries, and from copper-cadmium alloy scrap.'
    substitutes:
      - 'USGS: batteries with other chemistries, particularly lithium-ion, can replace NiCd batteries; zinc-nickel can be substituted for cadmium in many plating applications.'
    abundance: 'USGS: quantitative reserve estimates for cadmium were not available; the cadmium content of typical zinc ores averages about 0.03%.'
    source: usgs-mcs2026-cadmium
    where: Import Sources (2021 to 2024) paragraph (China 50%, Germany 33%); Recycling; Substitutes; World Resources paragraph; critical list status from the USGS list page
  - subject: Lead
    producers:
      - country: China
        share_percent: 42.2
        year: 2025
      - country: Australia
        share_percent: 10.7
        year: 2025
      - country: Peru
        share_percent: 6.4
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals
        listed: true
    recycling: 'USGS: an estimated 1 million tons of secondary lead was produced in 2025, equivalent to 70% of apparent domestic consumption.'
    substitutes:
      - 'USGS: plastics have reduced the use of lead in cable covering and cans, and steel and zinc are common substitutes for lead in wheel weights.'
    source: usgs-mcs2026-lead
    where: World Mine Production and Reserves table (2025e, thousand metric tons lead content; world total 4,500; shares calculated by Space Mushroom from China 1,900, Australia 480 and Peru 290); Recycling; Substitutes; the 2025 list text
  - subject: Tin
    producers:
      - country: China
        share_percent: 24.5
        year: 2025
      - country: Indonesia
        share_percent: 21
        year: 2025
      - country: Peru
        share_percent: 11.4
        year: 2025
    critical_lists:
      - list: USGS 2025 List of Critical Minerals
        listed: true
    recycling: 'USGS: about 17,000 tons of tin from old and new scrap was estimated to have been recycled in 2025, accounting for 22% of apparent consumption.'
    substitutes: []
    source: usgs-mcs2026-tin
    where: World Mine Production table (2025e; world total 290,000 t; shares calculated by Space Mushroom from China 71,000, Indonesia 61,000 and Peru 33,000); Recycling; critical list status from the USGS list page
documents:
  - title: 'Mineral Commodity Summaries 2026: Bismuth (USGS)'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-bismuth.pdf
    year: 2026
  - title: 'Mineral Commodity Summaries 2026: Cadmium (USGS)'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-cadmium.pdf
    year: 2026
  - title: 'Mineral Commodity Summaries 2026: Lead (USGS)'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-lead.pdf
    year: 2026
  - title: 'Mineral Commodity Summaries 2026: Tin (USGS)'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tin.pdf
    year: 2026
  - title: About the 2025 List of Critical Minerals (USGS)
    type: report
    url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals
    year: 2025
  - title: Wood's metal (encyclopedia article)
    type: database
    url: https://en.wikipedia.org/wiki/Wood%27s_metal
    year: 2026
  - title: Fusible alloy (encyclopedia article, table of well-known alloys)
    type: database
    url: https://en.wikipedia.org/wiki/Fusible_alloy
    year: 2026
  - title: Bismuth (encyclopedia article, physical properties and toxicity)
    type: database
    url: https://en.wikipedia.org/wiki/Bismuth
    year: 2026
  - title: Experimental study of the electrical conductivity, density and viscosity of a wood alloy (Kazandzhan et al., 1989, Russian)
    type: paper
    url: https://www.mathnet.ru/eng/tvt3860
    year: 1989
  - title: ASM Alloy Digest, CERROBEND Alloy (abstract)
    type: datasheet
    url: https://dl.asminternational.org/alloy-digest/article/27/8/Bi-6/4286/CERROBEND-AlloyLow-Melting-Controlled-Shrinkage
    year: 1989
  - title: 'PubChem compound record: Cadmium (CID 23973), GHS classification and density'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Cadmium
    year: 2026
  - title: 'PubChem compound record: Lead (CID 5352425), GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/5352425
    year: 2026
  - title: 'PubChem compound record: Tin (CID 5352426), GHS classification'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/5352426
    year: 2026
gaps:
  - Thermal conductivity of Wood's metal was not found in any source read. The thermal-conductivity search returned only supplier pages that state no number.
  - Specific heat, latent heat of fusion and thermal expansion of Wood's metal were not found in any source read.
  - Room-temperature density of the nominal alloy was not read on a fetched page. A vendor listing gives 9.7 g/cm3 at 20 °C, but it was seen only in a search result and the vendor page could not be opened.
  - Electrical conductivity and viscosity of the 1989 industrial alloy are given in the paper as equations and a figure, not as single values, so they are not recorded.
  - No corrosion, oxidation or galvanic-corrosion data for Wood's metal were found, so the corrosion list is empty.
  - No UNS, EN, ASTM or JIS designation for Wood's metal was found in any source read.
  - Tensile strength, hardness and elongation of Wood's metal were not found beyond the two room-temperature values from Wikipedia, whose underlying test is not named.
  - The 1989 paper's composition differs from the nominal 50/26.7/13.3/10 alloy, and its density and solidification values apply to that composition only.
  - No space, vacuum, outgassing, UV, atomic-oxygen or radiation data for Wood's metal were found. The uses listed are ground uses.
  - Supplier pages (VWR, Sigma-Aldrich and ThomasSci) could not be opened, so no supplier SDS or hazard statement for the alloy itself was read. The hazard data are for its constituents.
  - Lipowitz's alloy (about 70.9 °C, Bi 49.5, Pb 27.3, Sn 13.1, Cd 10.1, from the Wikipedia fusible-alloy table) is a different composition, so it is not used as a Wood's metal value.
sources:
  wikipedia-woods-metal:
    title: Wood's metal, Wikipedia (lead section, applications section, toxicity section)
    url: https://en.wikipedia.org/wiki/Wood%27s_metal
    kind: web
    license: CC BY-SA 4.0, linked not reproduced
  wikipedia-fusible-alloy:
    title: Fusible alloy, Wikipedia (table of well-known alloys)
    url: https://en.wikipedia.org/wiki/Fusible_alloy
    kind: web
    license: CC BY-SA 4.0, linked not reproduced
  wikipedia-bismuth:
    title: Bismuth, Wikipedia (infobox physical properties, lead section)
    url: https://en.wikipedia.org/wiki/Bismuth
    kind: web
    license: CC BY-SA 4.0, linked not reproduced
  kazandzhan1989:
    title: Experimental study of the electrical conductivity, density and viscosity of a wood alloy (Kazandzhan, Matveev, Savich, Umarov; Teplofizika vysokikh temperatur 27:2, 1989, Russian)
    id: Teplofizika vysokikh temperatur 27:2, pp. 269-273, paper 3860 (mathnet.ru)
    url: https://www.mathnet.ru/php/getFT.phtml?jrnid=tvt&paperid=3860&what=fullt&option_lang=eng
    kind: paper
    license: journal page, cited not reproduced
  asm-cerrobend:
    title: ASM Alloy Digest, CERROBEND Alloy, low-melting controlled shrinkage (Bi-6)
    id: ASM Alloy Digest, abstract only (full datasheet paywalled)
    url: https://dl.asminternational.org/alloy-digest/article/27/8/Bi-6/4286/CERROBEND-AlloyLow-Melting-Controlled-Shrinkage
    kind: datasheet
    license: ASM, cited not reproduced
  usgs-mcs2026-bismuth:
    title: 'Mineral Commodity Summaries 2026: Bismuth (U.S. Geological Survey)'
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-bismuth.pdf
    kind: report
    license: public domain (USGS)
  usgs-mcs2026-cadmium:
    title: 'Mineral Commodity Summaries 2026: Cadmium (U.S. Geological Survey)'
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-cadmium.pdf
    kind: report
    license: public domain (USGS)
  usgs-mcs2026-lead:
    title: 'Mineral Commodity Summaries 2026: Lead (U.S. Geological Survey)'
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-lead.pdf
    kind: report
    license: public domain (USGS)
  usgs-mcs2026-tin:
    title: 'Mineral Commodity Summaries 2026: Tin (U.S. Geological Survey)'
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-tin.pdf
    kind: report
    license: public domain (USGS)
  usgs-crit2025:
    title: About the 2025 List of Critical Minerals (U.S. Geological Survey)
    url: https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals
    kind: report
    license: public domain (USGS)
  pubchem-cadmium:
    title: 'PubChem compound record: Cadmium (CID 23973), GHS classification and density'
    id: CID 23973
    url: https://pubchem.ncbi.nlm.nih.gov/compound/Cadmium
    kind: database
    license: public domain (NCBI)
  pubchem-lead:
    title: 'PubChem compound record: Lead (CID 5352425), GHS classification'
    id: CID 5352425
    url: https://pubchem.ncbi.nlm.nih.gov/compound/5352425
    kind: database
    license: public domain (NCBI)
  pubchem-tin:
    title: 'PubChem compound record: Tin (CID 5352426), GHS classification'
    id: CID 5352426
    url: https://pubchem.ncbi.nlm.nih.gov/compound/5352426
    kind: database
    license: public domain (NCBI)
license: CC-BY-4.0
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 6
  unreachable: 4
  caveats: 4
  note: 'Read by an AI assistant on 2026-10-26. Six numeric properties are sourced: two from the Wikipedia article (melting point, room-temperature modulus and yield strength), one from the 1989 paper (solidification temperature and density, for a different composition), and one from the ASM abstract. Unreachable: VWR, Sigma-Aldrich and ThomasSci supplier pages (blocked or empty), and the MDPI review (blocked). Caveats: the Wikipedia values carry no test conditions; the 1989 alloy is not the nominal composition; the hazard data are for the constituents; no thermal or corrosion value was found.'
story:
  recipe:
    line: Wood's metal is a eutectic alloy, a mixture of four metals that melts at one fixed temperature. Its nominal composition is 50% bismuth, 26.7% lead, 13.3% tin and 10% cadmium by mass (Wikipedia). The sources read do not describe how it is made.
    parts:
      - name: Bismuth
        symbol: Bi
        share_percent: 50
        role: The largest share. Wikipedia describes elemental bismuth as having unusually low toxicity for a heavy metal.
      - name: Lead
        symbol: Pb
        share_percent: 26.7
        role: 'A heavy, soft component. Its share varies between sources: the 1989 paper gives 40.3 to 41.2 mass % for an industrial alloy.'
      - name: Tin
        symbol: Sn
        share_percent: 13.3
        role: A component of the alloy. The sources read give the share but not its individual effect on the melting point.
      - name: Cadmium
        symbol: Cd
        share_percent: 10
        role: A component of the alloy. PubChem's aggregated notifications for cadmium carry most of the alloy's hazard codes.
  risk_groups:
    - title: For people
      lead: The alloy contains lead and cadmium. The sources read say its fumes are toxic and that contact with bare skin is considered harmful.
      points:
        - label: Cadmium and lead
          line: PubChem's ECHA aggregate for cadmium reports H350 (may cause cancer) and H330 (fatal if inhaled) at 92.2% of company reports. For lead it reports H360 (may damage fertility or the unborn child) at 84.4%.
        - label: Fumes and dust
          line: Wikipedia says the fumes are toxic and the dust may form flammable mixtures with air. Cadmium vapour from cadmium-containing alloys is a danger to humans.
        - label: Bismuth
          line: Elemental bismuth has unusually low toxicity for a heavy metal (Wikipedia), so the bismuth share is not the hazard.
    - title: If it overheats
      lead: The alloy melts near 70 °C. Above that temperature it no longer behaves as a solid.
      points:
        - label: Melting
          line: Wikipedia gives an approximate melting point of 70 °C (158 °F). A 1989 measurement of an industrial alloy gives a solidification temperature of 343 K (70 °C).
        - label: Strength
          line: The room-temperature modulus of 12.7 GPa and yield strength of 26.2 MPa do not apply above the melting point.
    - title: Handling and storage
      points:
        - label: Skin and fume
          line: Wikipedia says contamination of bare skin is considered harmful and that the fumes are toxic. PubChem's cadmium record lists precautionary codes P260, P264, P270 and P280.
        - label: Storage
          line: No storage guidance for the alloy was found in any source read.
  why: Wood's metal is a eutectic alloy, meaning it has one fixed melting point below those of its parts. It melts at about 70 °C, which is why it is used for fusible links that must release near that temperature. Barnabas Wood invented and patented it in 1860 (Wikipedia). The alloy's weak points are its toxicity, from cadmium and lead, and the few physical data available for it.
  uses:
    - where: Fire-sprinkler fusible links
      line: Wikipedia says the alloy is used for fusible links in commercial sprinkler heads, where it melts in a fire to release water. USGS lists bismuth fusible alloys as a triggering mechanism for fire sprinklers.
    - where: Medical radiation treatment
      line: Wikipedia says the alloy is used to make custom-shaped apertures and blocks for medical radiation treatment. This is a ground use.
    - where: Heat-transfer baths
      line: Wikipedia says the alloy can be used as a heat-transfer medium in hot baths.
  can_do:
    - label: Melt low
      value: 70 °C melting point
      benchmark: melting_point
      line: Wikipedia gives about 70 °C (158 °F) for the eutectic composition, and an ASM abstract gives the same figure for Cerrobend, which Wikipedia lists as identical.
    - label: Stiffness
      value: 12.7 GPa modulus
      benchmark: elastic_modulus
      line: Wikipedia gives a modulus of elasticity of 12.7 GPa at room temperature. The test is not named.
    - label: Strength
      value: 26.2 MPa yield
      benchmark: yield_strength
      line: Wikipedia gives a yield strength of 26.2 MPa at room temperature. The test is not named.
    - label: Weight
      value: 10.15 g/cm3
      benchmark: density
      line: The 1989 paper gives a density of 10.15 g/cm3 on solidification for an industrial alloy with more lead than the nominal composition.
  compare: The sources read for Wood's metal are few and mostly secondary. The density comes from a different composition, and no thermal value was found. The comparison rows therefore show only melting point, density and stiffness.
  compare_rows:
    - label: Melting point
      benchmark: melting_point
    - label: Density
      benchmark: density
    - label: Stiffness
      benchmark: elastic_modulus
  handling:
    - Avoid skin contact. Wikipedia says contamination of bare skin is considered harmful.
    - Do not breathe fume or dust. Wikipedia says the fumes are toxic and the dust may form flammable mixtures with air.
    - Keep the composition in view when comparing values, because lead content varies between sources.
  good_for:
    - Low-melting releases near 70 °C, such as fusible links in sprinkler heads (Wikipedia).
    - Holding fixtures and plugs where a fixed low melting point is needed (USGS lists bismuth fusible alloys for these uses).
  watch_out:
    - 'Toxicity: cadmium (10%) and lead (26.7%) are the hazards of the alloy.'
    - 'Composition varies: the 1989 industrial alloy had about 40 to 41 mass % lead, against 26.7% in the nominal alloy.'
    - 'Few physical data: no thermal conductivity, specific heat or corrosion value was found in any source read.'
  verdict: Wood's metal is a low-melting fusible alloy that melts at about 70 °C. It is used for sprinkler links, fusible plugs and holding fixtures. Its toxicity comes from cadmium and lead, and the physical data available are few and partly from a different composition.