Pewter: What It Is, Properties, Importance, Uses, and Advantages
Pewter is a tin-based alloy, meaning it is composed of other metals including tin. Pewter is an old alloy found in ancient Egypt and ancient Rome. The ancient form of pewter is different from modern forms of pewter as it used to contain lead, whereas now it uses antimony and copper instead. Pewter's unique characteristics are that it is cheap and malleable, which leads it to be used in jewelry, tableware, and decorative pieces.
This article will discuss pewter, its properties, importance, uses, advantages, as well as disadvantages.
What Is Pewter?
Pewter is a dull gray alloy metal that is predominantly made of tin. It is known for its use in decorative pieces and utensils as it is easily formed into complex shapes. Originally, pewter was a 70% tin and 30% lead mix. However, the lead reacted with acidic food which it came into contact with, which earned it the name “black metal.” This is because it became darker with time. Now, pewter is generally 91% tin, 7.5% antimony, and 1.5% copper.
What Are the Physical Properties of Pewter?
Table 1 below highlights the physical properties of pewter:
| Physical Properties | Definition | Value |
|---|---|---|
Physical Properties Tensile strength | Definition Has a relatively low tensile strength compared to other basic alloys such as steel (which has a tensile strength of 420 MPa) | Value 59 MPa |
Physical Properties Modulus of elasticity | Definition Very malleable and ductile and can be easily formed into shapes by hammering or similar methods without cracking | Value 53 GPa |
Physical Properties Low Melting Point | Definition Can be easily cast into shape | Value 471–563 °F |
Physical Properties Shiny | Definition Comparable to silver | Value Highly reflective |
| Chemical Properties | Definition |
|---|---|
Chemical Properties Reactive | Definition Over time will react with oxygen in the air and tarnish. |
Chemical Properties Flammable | Definition In powdered form, it is highly flammable. However, it is not flammable in solid form. |
Chemical Properties Non-toxic | Definition Traditional pewter contains toxic lead, however, modern forms of pewter use copper and antimony instead, meaning pewter is now non-toxic. |
What Is the Importance of Pewter?
Pewter is an important metal used in the creation of dishes, utensils, religious artifacts, and decorative items. It is easily workable and is a common alloy made from available resources. Pewter is mainly used in utilitarian products as well as some ornamental products, in place of other more expensive metals.
What Are the Different Uses and Applications of Pewter?
Pewter has a long list of applications which include:
- Jewelry, such as: plated rings, necklaces, and bracelets.
- Flasks, such as: hip flasks, tankards, and pint cups.
- Tableware such as cutlery and dishes.
- Candle holders such as candelabra, candlestick holders, and pricket-base candle holders.
- Light fittings such as pendant fittings, chandelier fittings, and wall fittings.
How Is Pewter Used in the Manufacturing Process?
Pewter is formed through a melting and casting process. In the first stage, the tin and lead (traditional pewter) or tin, antimony, and copper (modern pewter) are melted in a furnace to combine the alloying elements. Once the pewter has melted, it will then be cast into a steel or sand mold tool. The pewter solidifies in the cast and is then removed and post-processed into its final form.
Is Pewter Used in Die Casting?
Yes, pewter is used in the die-casting process to enable mass production of pewter pieces. One reason for this is that pewter is easily melted due to its low melting point. This molten metal can be poured into a cast made commonly of steel or sand. Once the molten pewter is solidified, it can be taken out of its cast and formed into its final shape.
Does Pewter Have High Tensile Strength?
No, pewter does not have a high tensile strength. The tensile strength of pewter will vary depending on its composition of alloying metals. However, 92-8 pewter has a tensile strength of 59 MPa and can be increased by increasing the antimony or copper content. However, this is still relatively low when compared to another alloy, such as steel, which has a tensile strength of around 420 MPa.
To learn more, see our guide on Tensile Strength Materials.
Is Pewter a Type of Metal?
No, pewter is not strictly a metal. Although pewter is made up of metals, it is classed as an alloy. An alloy is defined as a material that consists of two or more metals that are combined to produce a material with more-desirable properties.
Is Pewter an Alloy?
Yes, pewter is an alloy. Pewter is classed as an alloy as it is composed of more than two metals, (one variation of the proportions of these metals is) tin 91%, antimony 7.5%, and copper 1.5%. The addition of antimony and copper to pewter gives the alloy extra strength.
To learn more, check out our guide on Alloy Properties.
Where Can You Find Pewter?
Pewter can be found in the form of tableware, decorative pieces, and religious artifacts all over the world. The earliest forms are found in Egyptian times, then Roman times, and later in Europe and Britain. In the 18th century, it was also exported to America and Canada, however, it saw limited production and stayed mostly within Europe.
What Are the Sources of Pewter?
Pewter is made from three metals:
- Tin
- Antimony
- Copper
How Is Pewter Mined?
Pewter is an alloy, which means its constituent components are gathered separately and combined. Its main constituent metal, tin, is produced by mining for “cassiterite” in underground mineral deposits. Tin is then separated from cassiterite for use in pewter or other alloys. The most popular way of mining tin is by using a gravel pumping method. In this method, the sedimentary deposit is extracted from the ground using draglines. This sediment is then blasted by high-pressure water jets to separate the sand and tin mixture. This mixture then forms part of a slurry which is picked up by a gravel pump and fed into a series of baffled boxes. In these boxes the cassiterite sinks which allows it to be removed.
What Are the Different Types of Pewter?
There are many different types of pewter that vary in composition. They are listed and described below:
1. Traditional Pewter
Traditional pewter has a different composition from modern pewter as it often contains more lead. Traditional pewter composition varies, but will generally consist of 85-99% tin and a mixture of copper and lead. For many applications, modern pewter is different from traditional pewter as lead is substituted for antimony. Traditional pewter dates back to the Egyptian and Roman times when pewter was used for many applications including: tableware, tankards, candlesticks, oil lamps, and jewelry.
2. Modern Pewter
While there are pewter applications that still use lead, such as solder wire, many modern pewter are free from lead, such as those used for jewelry. The composition of modern pewter will vary. However, it is generally made of at least 90% tin, 0.58% antimony, and up to 2.3% copper. Similar to traditional pewter, it does not have good strength which is why it is not used in any form of structure or load-bearing application.
3. Britannia Metal
Also referred to as Britannium, Britannia metal is made up of 91–93% tin, with the addition of tin and antimony for hardening and strengthening. It is formed using spin-cast molds. A spin-cast mold resembles the regular casting method, however, the mold is spun while the metal is still molten. Britannia is lead-free and is used in jewelry and to make Oscar award statues.
4. Lead-Free Pewter
Lead-free pewter comes in a range of different compositions with the unifying factor being the absence of lead. Lead-free pewter is cast using an open mold. The mold tools are often made of iron or sand and so use a refractory liner to prevent sticking. Lead-free pewter is used to make jewelry and game pieces.
5. Antique Pewter
Antique pewter is the same alloy as modern pewter, however, antique pewter refers to collectibles from an older time period. The main difference between antique pewter and modern pewter is that, if not properly cleaned, antique pewter will have reacted with the oxygen in the air and created an oxide layer. This oxidation creates a dull gray or even black finish, compared to modern pewters’ reflective silver finish.
6. 25% Tin Pewter Alloy
25% tin pewter is the cheapest pewter on the market. It is a denser pewter variety used to make cheap products in which high weight is not an issue. The high weight is due to the large portion of lead used in the composition. Lead makes up for 74% of the composition of 25% tin pewter while the remaining 2% is antimony. 25% tin pewter is not typically used for jewelry pieces due to their weight but is used for candle fixtures instead.
7. 35% Tin Pewter Alloy
35% tin pewter has a fairly low melting point and is relatively malleable in contrast to other pewter alloys. Similarly to 25% tin pewter, a large proportion of the material composition is lead at 62%, with the remaining 3% of the composition made up of antimony. 35% tin pewter offers a trade-off between the low melting point and good castability of 60% tin pewter, and the low cost of the more dense and therefore heavy 25% tin pewter.
8. 60% Tin Pewter Alloy
60% tin pewter is also composed of 37.5% lead and 2.5% antimony. 60% tin pewter has the lowest melting point of any pewter. This extends the mold life used in the casting process and reduces energy costs in production. This reduced the cost of this form of pewter. 60% tin pewter’s most common use is as solder for electrical connections, however, it is also known to be used for handles, spouts, and hinges.
9. Special 92% Tin Pewter
92% tin alloy is especially good for casting, even better than Britannia pewter. This pewter is used for making models and figurines. This is because 92% tin pewter flows well in the molten state and so can be used for intricate moldings.
10. Tin Base Level Alloy 1
Tin base level alloy 1 is a composition made specifically for moldings with flat surfaces which require a polished finish. This alloy is made of 90% tin, 2% antimony, 2% cadmium, and 6% lead.
What Are the Advantages of Pewter?
Pewter has many useful benefits which include:
- Low cost.
- Malleability.
- Ductility.
- Low melting point.
- Low viscosity for intricate casting.
What Are the Disadvantages of Pewter?
There are reasons why pewter is not a desirable material and they are:
- Susceptible to tarnishing.
- Low strength.
- Not relatively durable.
Why Is Pewter Considered Harmful?
Pewter is considered harmful due to the misconception that it is made with lead. This is because traditional pewter was made with lead. However, this is not the case for the majority of pewter used today. Instead, more pewter is now made with tin, antimony, and copper. It is still recommended that anyone handling pewter that is unsure of its composition should take precautions to prevent lead poisoning.
Can You Recover From Pewter Poisoning?
Yes, you can recover from pewter poisoning. If you have high exposure to traditional pewter which contains lead, then the lead will react with your skin and cause lead poisoning. Symptoms of lead poisoning include:
- High blood pressure.
- Joint and muscle pain.
- Loss of memory.
- Headaches.
- Abdominal pain.
- Mood swings.
- Low sperm count.
Lead poisoning can be treated, but first exposure to the pewter containing lead must be stopped. A patient will then receive chelation therapy, where succimer medication is taken orally. Succimer medication will bind with lead particles leading to the lead being excreted.
Summary
This article presented pewter, explained it, and discussed its importance and various applications. To learn more about pewter, contact a Xometry representative.
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