Noble Thermocouple Wire (Type R/S/B)
Torch the bare wire end for five seconds — Pt/Rh stays mirror-white and dead soft; chromel/alumel instantly goes grey-black and stiffens, and alumel sticks to a magnet. Magnet plus flame is the whole test.
How to spot it
Two silvery-white, very soft, very heavy hair-fine wires 0.25–0.51 mm threaded through a twin-bore high-purity alumina insulator inside a white recrystallised-alumina or SiC sheath, terminating in a cast head. ANSI MC96.1 jackets: R = black, S = green, B = grey (K = yellow, J = black, T = blue). Heads marked TYPE S, TYPE B, Pt/Pt-10%Rh, Omega, Watlow, Thermo Electric or Nanmac. Found in glass furnaces, foundries, cement kilns, crystal pullers, diffusion furnaces and calibration labs.
Metal content
| Metal | Quantity | Notes |
|---|---|---|
| Platinum | ~410 g per lb of bare noble wire | Type S is Pt/Pt-10%Rh; 0.50 mm pair is 8.42 g/m. Blended $65.02/g for S, $67.97 for R, $90.56 for B |
| Base metal | Rh 6–30% of one leg | Rh is not separately quoted here but materially changes value — B is 39% more per gram than S |
| Base metal | Type K/J/T/E/N: zero PGM | Ni-alloy or Cu scrap at $0.80–3.50/lb |
At 4 Aug 2026 spot prices that works out to $22,633 per pound of contained metal — Platinum 410 g = $22,633. A refiner paying $26800 returns about 118% of that, which is normal: refining costs money and the buyer takes a margin.
Safe removal
Working temperature: Torch test only; no processing heat
Wrap the ceramic sheath in cloth and tap with a hammer — the alumina is brittle and worthless. Slide the twin-bore insulator off and snip the noble wire where it is welded to the copper or compensating extension wire; that weld joint is the boundary of value. Do not melt or home-refine — let a PGM refiner assay the actual Rh ratio, and keep types separated by colour or a mixed lot gets valued to the lowest denominator.
Hazards
NEVER dry-cut boards indoors without extraction.
NEVER vacuum a mercury spill — it aerosolises it. Use a mercury spill kit or sulphur powder, or call your local hazmat line.
NEVER grind, sand, saw or incinerate anything that might contain thorium or radium. Sealed sources stay sealed.
The practical answer for nearly everyone: sort, concentrate, and sell to a licensed refiner. A good refiner recovers 85–98%, assays rather than guesses, pays on the assay, and takes the waste liability. Your edge as a scrapper is identification and sorting — not chemistry.
Before you scrap it
The common trap
Questions
How much gold is in noble thermocouple wire (type r/s/b)?
Platinum: ~410 g per lb of bare noble wire. At current spot that is about $22,633 of contained metal per pound.
How do you identify noble thermocouple wire (type r/s/b)?
Torch the bare wire end for five seconds — Pt/Rh stays mirror-white and dead soft; chromel/alumel instantly goes grey-black and stiffens, and alumel sticks to a magnet. Magnet plus flame is the whole test.
How do you remove noble thermocouple wire (type r/s/b) safely?
Wrap the ceramic sheath in cloth and tap with a hammer — the alumina is brittle and worthless. Slide the twin-bore insulator off and snip the noble wire where it is welded to the copper or compensating extension wire; that weld joint is the boundary of value. Do not melt or home-refine — let a PGM refiner assay the actual Rh ratio, and keep types separated by colour or a mixed lot gets valued to the lowest denominator.
Is noble thermocouple wire (type r/s/b) worth more working than as scrap?
Modest premium, unusually — an unused R/S/B assembly fetches only 110–140% of metal because industrial buyers also price off spot. Base-metal K/J/T probes are the opposite: $15–60 working versus $0.05 scrap, a 300× ratio, so never scrap an intact base-metal probe.
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