Archive for February, 2013

Types of platinum thermocouple wire

Platinum thermocouple wire

A thermocouple is quite simply a sensor for measuring temperature, with many applications from central heating boilers to jet engines. Thermocouples use the reaction of two dissimilar metals to measure temperature variation. The types of metal involved vary according to the temperature range in which the thermocouple operates.

Some thermocouples use relatively inexpensive alloys such as nickel, chrome, iron and aluminium. The thermocouples we’re interested in, known as Types B, R and S, use platinum – a rare and expensive material that is one of the noble metals (which also include silver and gold).

Platinum, rare and valuable

Platinum has the chemical symbol Pt and the atomic number 78, and is twice the density of silver. One of the rarest elements on Earth and extremely valuable, it is mined mostly in South Africa. As an indication of its value, the crown worn by Queen Elizabeth the Queen Mother, as Consort of King George VI, had a frame made of platinum. Though the crown was undoubtedly spectacular, the platinum frame added significantly to its weight; a solid six inch cube of platinum weighs as much as an adult man.

We don’t expect you to send us the Queen Mother’s crown for valuation! However, though the platinum wire used in thermocouples is a relatively small diameter, its value makes it well worth selling to Gold-Traders.

Platinum qualities

Why platinum? It cannot be oxidised, withstands most acids, has high resistance to corrosion and high temperatures, and is electrically stable and an efficient conductor. In thermocouples, platinum is often combined in an alloy with rhodium, a chemically inert transition metal which is also part of the platinum group.

Types of platinum thermocouple

The ratio of platinum to rhodium depends on the type of thermocouple.

Type B Thermocouple Wire

For a Type B thermocouple, one conductor will be 70% platinum, 30% rhodium, while the other will be 94% platinum, 6% rhodium. Type B thermocouples are used for very high temperature measurements, with a usable range of around 800°C to 1800°C.

Type R Thermocouple Wire

A Type R thermocouple will have one conductor with 87% platinum, 13% rhodium, and the other conductor 100% pure platinum. It’s used for temperatures up to 1600°C, in applications such as the steel industry.

Type S Thermocouple Wire

The Type S thermocouple can also withstand heat up to 1600°C, and has one conductor that’s 90%, 10% platinum and the other 100% pure platinum. A typical application for Type S is providing the calibration standard for the melting point of gold (1064.43°C). It’s also used in pharmaceutical and biotechnology applications.

Scrap Thermocouple Prices

  • Type B: £ (70% conductor) & £ (94% conductor)
  • Type R: £ (87% conductor) & £ (100% conductor)
  • Type S: £ (90% conductor) & £ (100% conductor)

Selling Thermocouple Wire

Unlike other dealers, the prices we quote are the prices we pay. We have no hidden deductions and don’t charge testing or refining fees.

To sell your thermocouple wire, please complete our claim form. Once submitted, you’ll be asked to print a copy for signing and we’ll give you full instruction regarding packaging and postage. All packages are dealt with on the day of receipt, Monday to Friday. If you have any other questions, please feel free to give us a call to discuss.

February 28th, 2013 1 Comment » Platinum |

Why Gold & Silver Fairs are unfair to sellers

A Philip & Sons flyer adverting a local gold buying event.

  • Gold & Silver buying events are tempting, but their only real value is entertainment – you could lose out heavily if you sell there.
  • Beware promoter’s extravagant claims. They rarely stand up to scrutiny.

If you’ve seen a leaflet advertising a gold and silver buying event or fair at a local venue, such as a hotel or community centre, don’t rush to sell your valuables there. You could get far less than they are really worth.

Gold and Silver Fairs are promoted with tempting claims. Take the local event being staged by Philip & Sons, which seems like a reputable company with its Mayfair address.

Worthless claims on Philip & Sons flyer

Top London cash prices paid”, says their flyer, although what actually constitutes a top London cash price is unclear. It also promises, “We pay better than all the rest” and “No one offers more!These claims are unsupportable and untrue.

Let’s look at their flyer in more detail. Apparently Philip & Sons will pay a minimum six times face value for pre-1946 silver coins. Putting aside the inaccuracy that the critical date for silver content in coins is actually pre-1947, the rates quoted certainly don’t match the adjacent claim “No one offers more!” Gold Traders is currently paying well over 10 times face value. Even if you’re just selling a handful of coins, that’s a worthwhile difference.

See what you could lose

For example, at six times face value, Philip & Sons would pay 72 pence for a pre-47 shilling; we would pay £1.29. For a Florin (remember those – they were worth two shillings), it would be £1.44 from Philip & Sons, £2.58 from Gold Traders. The greater the face value, the more you’d lose out by selling to Philip & Sons rather than Gold Traders; for a Half Crown it’s £1.80 vs. £3.24, and for a Crown it’s £3.60 vs. £6.49. You could almost double your money.

We’ll point out right now that as we pay by weight, these prices are an illustration and rates will vary according to wear as well as the current silver price. Having said that, Gold Traders will pay you considerably more than Philip & Sons for even heavily worn coins.

Dramatic difference

The difference is even greater with Sovereigns. The Philip & Sons flyer promises a minimum £65 for a Half Sovereign and £130 for a Full Sovereign. Our current prices are almost double – currently £115.05 for a Half Sovereign and £230.09 for a Full Sovereign.

(Note: Above prices were correct at time of writing. Up-to-date rates are available by clicking the appropriate links.)

Not so much fun at the fair

So while selling your gold and silver at hotel or community centre buying fairs may seem convenient, you’re likely to lose out significantly. It’s best to treat these events purely as free entertainment, and sell to Gold Traders instead – where you’re always sure of a fair exchange.

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February 22nd, 2013 3 Comments » Selling Tips |