# Liquid Hardware & Metal Contact
Human page: https://retifist.com/literature-reviews/liquid-hardware-metal-contact
## Executive summary
Wet latex and leach water: no copper, brass, or galvanized iron in compound, process equipment, or leach-water fittings.[^1][^2] Dithiocarbamate-cured deposits stain brown from minute copper traces; wet deposits are especially prone.[^5] Dry dipped or cast film still takes copper-catalyzed oxidative aging.[^3][^4]
Cut-sheet snaps: [Sheet Hardware & Metal Contact](/literature-reviews/sheet-hardware-metal-contact). Contact grid: [Compatibility Matrix](/literature-reviews/compatibility-matrix-metals-oils-plastics).
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## Wet latex and leach water
Metal fittings that touch latex: black iron, stainless steel, or another material not harmful to latex. Brass or copper fittings cause serious deterioration of the rubber in the latex. Galvanized fittings cause coagulum.[^1]
Dipped-goods compounding and process equipment: free of copper, brass, or galvanized iron.[^2] Warm-water leach tank: same metal rules as the dip tank. Fittings and pipes that bring water in must not contain copper or brass. Do not reuse leach water unless leached materials have been removed.[^2]
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## Copper stain on wet or fresh film
Dithiocarbamate accelerators: deposits become superficially brown from minute traces of copper (copper(II) dithiocarbamates). Wet, not-yet-dry deposits are especially prone. Coin-trace copper on hands is enough. Remedy: do not use dithiocarbamate accelerators.[^5]
Cast- or dip-film cure chemistry, not snap-install chemistry.
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## Cured dipped or cast film
Trace copper catalyzes unsaturated-rubber degradation after the film is dry. Copper-exposed NR or CR latex film: **2 phr** total antioxidant (1 phr oxidation + 1 phr copper reserve).[^3] Sudsai: copper oleate catalysis; dark spots from copper in containers.[^4]
Clean stainless is plant-acceptable for wet contact.[^1] Wear-time rating for sweat in a crevice on cured dipped film: not given in these sources.
Aging morphology: [Liquid Aging, Storage and Care](/literature-reviews/liquid-aging-storage-and-care).
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Deep dive: Concentrate metal limits
ISO 2004 / ASTM D1076 track Cu and Mn in concentrate specs (metal-poison recognition). Sudsai cites Thai copper limit ≤8 mg/kg total solids.[^4] Feedstock specs, not fastener-alloy grades.
Deep dive: Dithiocarbamate copper stain
No remedy for copper stain except accelerator-class change. Avoid copper contact with dithiocarbamate cures.[^5]
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## Endnotes
[^1]: Vanderbilt Latex Handbook — reception and storage of bulk latex; brass/copper deterioration; galvanized coagulum; black iron / stainless acceptable.
[^2]: Vanderbilt Latex Handbook — dipped gloves; no copper, brass, or galvanized iron in compounding, process, or leach-water fittings; leach water not reused unless cleaned.
[^3]: Vanderbilt Latex Handbook — antioxidant recommendations; 2 phr total for copper-exposed NR or CR film.
[^4]: Sudsai et al., ScienceAsia 43 (2017) — copper catalysis; container spots; Thai concentrate copper limit ≤8 mg/kg TSC.
[^5]: Blackley, Polymer Latices Vol. 3 — Application of Latices — dithiocarbamate copper stain (copper(II) dithiocarbamates); wet deposits; accelerator-class change.