Metal Casting

In relation to metalworking, casting is the process in which metal is liquefied and poured into a mold which is then cooled and solidified into the shape of the mold’s cavity. The solidified piece of metal also referred to as the casting or ingot is then released from the mold to complete the process. There are different types of casting methods including; hand pouring, sand casting, investment casting, lost wax, spin, and centrifugal casting.

The casting process has been used for thousands of years for making sculpture, jewelry, tools and more. Here at PMC Supplies, we specialize in offering tools for both melting down precious and non-precious metals and pouring them into a mold. We carry graphite, steel, and cast iron molds to mention a few. These molds are offered in a variety of shapes and sizes to accommodate your specific needs. We also carry a full line of melting furnaces, crucibles, and torches for the initial melting process; as well as handling tools and safety gear for handling your metals during the casting process. Whether you are out mining for your own gold, have scrap jewelry you want to melt down, or simply practice metalworking as a hobby, we have the tools you need to cast your metals from start to finish!

Metal casting can be a lucrative hobby when dealing with precious metals. With the proper tools and equipment you can begin melting down your own gold, silver, and copper materials into bars or other forms for resale. We also carry all the necessary accessories and chemicals in order to refine your precious metals to an even more purified state, allowing you to get top dollar for your material.

Our Industries

• Minting, Bullion Exchanges, Precious Metal Refineries, Jewelry Making, & Dental

Types of Metal Casting

Metals can be melted using a torch, an electric, propane, induction furnace, or even a microwave melting furnace. Determining which method is best for you will depend on your budget, the type of material you are melting and the amount of material you wish to melt at one time.

Hand Pouring

First, metal is heated until it reaches a molten state. This is done so by using a crucible to hold your material and a heat source such as a melting furnace or a hand torch for melting. The metal is heated in a crucible to its specific melting point and then is poured into the mold of your choice to complete the process. *Be sure to pre-heat your graphite ingot molds to prevent thermal shock and cracking.

Sand Casting

An inexpensive casting method where a sand and clay mixture is used as the vessel in which to pour your molten metal. The sand/clay mixture is often contained in a metal flask or mold in order to be able to compact the material to a dense state for optimal pouring results. Due to its malleable texture, sand casting can be used to replicate intricate objects by pressing the object into the sand to leave a negative impression of the design that is then filled with your molten metal. You can also carve patterns or designs directly into the compacted sand. The mold is filled with the molten material which will then cool and harden. Once the metal has solidified, the mold can be hammered in order to crack the sand and expose the metal object.

Investment/Lost Wax Casting

Investment casting is one of the oldest casting methods where molten metal is poured into a ceramic mold. The mold is first formed to your specific design by creating a disposable wax pattern. The wax design is then completely surrounded or “invested” into a ceramic slurry which eventually solidifies into the mold. The term “lost wax casting” is used because the original wax design or pattern is melted out of the mold after the object has been formed. Lost wax casting is not the most efficient method if you wish to create multiples of the same design as each time a wax pattern is made; it is completely consumed during the process.

This casting method can be used with aluminum, bronze, cast iron, steel, and magnesium alloys and is best for casting metals with intricate detail or complex designs. This casting method will require molten metal, a metal die, wax, ceramic slurry, furnace, and a machine for grinding, cutting, or blasting.

Spin Casting/Centrifugal Casting

Spin casting or centrifugal casting is a method in which a rubber mold is produced by using centrifugal force. Molten material is poured into a cavity through a small opening at the top of a disc-shaped mold and the material is pushed against the cavity’s inner walls as the centrifuge moves at a specific speed. The mold is filled with the material and continues to spin as the metal or plastic begins to solidify inside of the hollow container. Spin casting is a commonly used non-expendable method for casting products that have great detail and surface finish such as fishing lures and tackle components, belt buckles, trophies, souvenirs, pins, and medallions.

Popular Metals for Casting and Their Melting Temperatures

Basic Metal Casting Tools and Supplies

Use the below list of suggested products to help you choose the right products for your application. Keep in mind that these are only suggestions and there are many different variables to take into consideration when choosing the right products for your melting needs.

Melting Furnaces

We offer a variety of Melting Furnaces and choosing the right one will depend on how much material you are looking to process at one time, the area where you plan on doing most of your melting, your budget, and of course your experience level.

Mini Kwik Kiln Propane Style

This melting furnace is great for beginners or people who are on the go since it is small enough to take with you on your prospecting travels. They area also ideal for those who are looking to process small amount of scrap jewelry, gold flakes, or other material.

Features:

• Stainless Steel shell
• Replaceable internal components
• Reaches 2100 degrees Fahrenheit in just a few minutes!
• Economical and uses inexpensive propane torches (not included)
• Portable, small,and lightweight

Propane-Pot Style

This melting furnace is great for melters with some prior experience and who are looking to process larger amounts of material at a time. This kiln will need to be used outdoors or in a well ventilated space.

Features:

• Sold in 2 Kg 4 Kg, and 10 Kg sizes to meet your melting needs
• Comes with DFC burner that will work with Propane, Butane, and Propane or Butane mix.
• Melts material in as little as 15 minutes!
• Designed and manufactured with heavy duty steel, ceramic wool and refractory cement to melt most metals
• No electricity makes this furnace easier to use

Digital/Electric Melting Style

These units are great for melters on either a commercial or hobbyist level of experience. This easy-to-operate machine can be used indoors on a safe, heat-resistance surface.

Features:

• Designed with a high temperature ceramic chamber for long lasting casting abilities
• Reaches max temperatures of 2102 degrees fahrenheit or 1150 degrees celsius
• Melts material in as little as 30 to 45 minutes!

Crucibles

You will need a heat-resistant vessel to liquify your material in during the melting process. Graphite and ceramic crucibles are both commonly used materials because of their extremely high melting points. Crucibles come in a variety of sizes, shapes, and materials. Choosing the right crucible will also depend on variables such as; the type of material you are melting, the amount of material you will be melting at one time, and your melting process (whether you are using a torch method or using a melting furnace of some sort).

Ceramic Crucibles

This style crucible is great for those who are using a torch method to melt their material. This crucible should be seasoned before using it to ensure your best results.

Features:

• Designed with tapered sides and pour spout for easy material removal.
• Suitable for melting precious metals in temperatures up to 2800°F.
• Ideal for smaller casting jobs
• Can be used to melt gold, silver, bronze, copper, brass etc.

Graphite Crucibles

We offer a variety of graphite crucibles that can be used with our different melting furnaces. Some units can handle multiple size variations depending on how big the batch of material is you are looking to melt. These crucibles are recommended for using while melting any precious materials.

Features:

• Most are designed with an outer lip for use with gripping tongs for easy handling.
• Last 30+ pours
• Excellent for melting precious and base metals
• Materials will not stick to the graphite material

Foundry or Pot-Style Crucibles

• Offered in a wide variety of sizes
• Suitable to use with propane and medium or high-heat induction furnaces
• Withstands extremely high temperatures

Silicon Carbide Crucibles

• More durable and long lasting than most graphite crucibles
• Can be used for melting, smelting, refining
• Use with precious and base metals

Fused Silica Crucibles

• This style crucible is used for melting gold, silver and other precious metals
• Can withstand temperatures up to 2200°F

Pouring Molds

You will need a mold to pour your melted material into in order to create a loaf, bar, coin, or ingot. We carry molds in a variety of materials including graphite, cast iron, and steel.

Graphite

Graphite is an ideal material for metal casting as it can withstand extremely high temperatures. Metals will release with ease and you will not require the use of a releasing agent or lubricating spray. We also offer customized engraved and custom shaped graphite ingot molds upon request. Graphite molds will start to deteriorate over time and after repeated use. Most customers find they can use a graphite mold between 30 to 60 pours before they need to be replaced. *The exact number of uses will vary.

Steel

Steel molds are also a great option and offer durability and longevity. They will last much longer than graphite but they do require a releasing agent or lubricating spray to be used before each pour to prevent the material from sticking to the mold. Our steel molds are offered in adjustable versions as well as wire strip molds. Our adjustable molds form your metal into a suitable shape for using in a rolling mill for further flattening.

Cast Iron

These are suitable for melting processes that do not require a smooth finish and are more commonly used for non-precious metals such as copper and brass. These molds are durable and will last many pours, but you will need to use a releasing agent or spray to lubricate your mold before pouring otherwise your metal can stick to the inner cavity of the mold.

Other Important Metal casting Tools & Supplies

Stir Rods

We recommend using a stir rod with your molten material during the melting process. They can also be used to skim and remove impurities from the surface of your melt.

Heat-Resistant Surface

Your tools will be extremely hot during your melting process and will need a safe place to rest when not in use. Some furnaces are also recommended to sit on a heat-resistant surface. Heat-resistant boards come in a variety of sizes and materials, each with their own specific heat capacity. These are also perfect surfaces for all of your soldering needs!

Safety Gear

You will need several types of heat-resistant safety gear in order to conduct your process safely, especially while working with such extreme temperatures. We recommend having a reliable pair of gloves, an apron, sleeves, face shield, protective eye goggles; and in some cases, a respirator for added safety.

Flux

You will most likely require a casting flux during your melting process. We sell several types of flux including anhydrous borax, boric acid, as well as Hank Chapman’s Flux. Flux is used for deoxidizing, seasoning crucibles, and helps to keep your material liquified, therefore providing better results.

Metal Casting Books

We highly recommend doing research and educating yourself before beginning a casting or refining project. There are many crucial steps, processes and safety measures you will need to be familiar with before successfully carrying out your project. If you are brand new to casting, or are somewhat experienced but are looking to expand your knowledge base, we offer a number of books that specialize in casting and refining.

Scales

You may want to invest in a digital scale of some sort to weigh your scrap and materials. We offer a variety of sizes from portable pocket-sized scales to larger tabletop scales.

Gold Testing Equipment

After you have melted and/or refined your material, you may want to test its purity. We offer testing acids, testing needles, digital testers, and special magnets to determine the purity of your material.

All-Inclusive Melting Kits

We have also designed a variety of all-inclusive melting kits that have everything you need to start melting your materials today! These kits are available with both electric and propane style furnaces and come with a variety of accessories to take the hassle out of selecting them individually, for a great value!