Best Graphite Mould Sizes for Gold Bars: 100g, 250g, 500g and 1kg
Choosing the right graphite mould size for gold bars is an important decision for bullion manufacturers, gold refineries, jewellers, precious metal dealers, and casting operations. The mould size directly affects the bar weight, production capacity, casting workflow, cooling time, handling, and overall production efficiency. Explore advanced graphite solutions and applications with our Graphite products and expertise. Among the most commonly used options are 100g, 250g, 500g, and 1kg gold bar graphite moulds. Each size is suited to a different production requirement, from smaller investment bars and retail products to larger bullion bars. High-quality graphite is widely used for precious-metal moulds because it offers good thermal stability, thermal conductivity, corrosion resistance, and easy release of cast metal. Commercial gold-bar moulds are available in configurations ranging from approximately 100g to 1kg and beyond. Quick Answer: Which Gold Bar Mould Size Is Best? The best graphite mould depends on your production requirement: Gold Bar Size Best Suited For Typical Mould Configuration 100g Retail bullion, jewellery businesses, smaller batches 4, 5, 10 or more cavities 250g Medium-size bullion production 2, 4 or multiple cavities 500g Professional bullion and refinery production 1, 2 or multiple cavities 1kg Large bullion bars and refinery operations Single cavity or multi-cavity For example, commercial casting systems can be configured to produce 1 × 1kg, 2 × 250g, 1 × 500g or 4 × 100g gold ingots, depending on the equipment and mould configuration. What Is a Graphite Mould for Gold Bars? A graphite gold bar mould is a precision-machined cavity used to shape molten gold into a defined bar or ingot size. The mould can be manufactured with one or multiple cavities, allowing operators to cast one or several bars during the same production cycle. For more precision in metal casting, explore our Square Graphite Casting Moulds, designed for reliable gold, silver, and other precious-metal bar casting applications. Graphite is particularly suitable for gold casting because it can withstand high temperatures and has good thermal conductivity. Fine-grain and high-density graphite can also provide a smooth mould surface, helping produce clean-looking bullion bars and facilitating bar removal after casting. The exact mould dimensions should not be selected only by external size. Cavity dimensions, gold purity, bar geometry, casting equipment, cooling conditions, and required bar weight all need to be considered. 1. 100g Graphite Mould for Gold Bars A 100g gold bar mould is one of the most practical choices for businesses producing smaller bullion bars. Why choose a 100g gold bar mould? 100g bars are convenient for retail bullion, investment products, jewellery manufacturers, and businesses that want to produce multiple smaller bars rather than one large bar. A tunnel furnace is a continuous heating system widely used in precious metals manufacturing, especially for producing gold and silver bars with consistent quality and high throughput. It allows controlled, uniform heating as metal moves through different temperature zones on a conveyor or track system. A multi-cavity mould can significantly increase output. For example, a four-cavity arrangement can produce four 100g bars in one casting cycle, subject to the capacity and design of the casting machine. Commercial examples of 100g graphite moulds include cavity dimensions around 35 × 20 × 10 mm, although dimensions vary according to bar design and manufacturer. Best applications Best choice when: your business needs flexibility and higher piece-count production. 2. 250g Graphite Mould for Gold Bars The 250g graphite gold bar mould provides a useful balance between bar size and production flexibility. A 250g bar is larger than a typical 100g retail bar while remaining relatively easy to handle and package. It can be a good option for bullion businesses targeting customers who prefer medium-sized investment bars. Explore our 1kg Gold Induction Melting Furnace – 4 Station IGBT System for efficient, high-precision melting that perfectly complements automated gold and silver bar casting operations. A commonly published graphite mould configuration for 250g gold ingots has an outer size of approximately 67 × 50 × 26 mm and a cavity around 47 × 25 × 16 mm, but actual dimensions depend on the required bar shape and density calculations. Best applications Why 250g can be a good choice The 250g format can offer a practical middle ground between production volume and individual bar value. For operations requiring multiple bars per cycle, a 2-cavity or 4-cavity 250g mould can be considered depending on the casting machine. 3. 500g Graphite Mould for Gold Bars A 500g graphite mould for gold bars is commonly used for professional bullion production and medium-to-large casting operations. Compared with a 100g or 250g bar, a 500g bar allows more gold to be produced per individual bar while remaining substantially smaller than a 1kg bar. Discover the Delmer iD Pro Series Induction Furnace, engineered for precision melting, energy efficiency, and superior performance. Published examples of 500g graphite moulds include external dimensions around 70 × 67 × 26 mm, with a cavity around 50 × 47 × 16 mm. Actual dimensions vary by manufacturer and bar profile. Best applications Single vs. multi-cavity 500g mould A single-cavity mould is suitable when production volume is moderate or when the casting system is designed for individual bars. For higher production requirements, multiple 500g cavities can increase the number of bars produced per cycle, provided the furnace, vacuum system, melting capacity, and cooling system are appropriately matched. 4. 1kg Graphite Mould for Gold Bars The 1kg graphite gold bar mould is one of the most important sizes for professional bullion and refinery applications. A 1kg gold bar contains significantly more metal than smaller retail formats and is commonly associated with professional bullion production and larger transactions. Experience seamless metal casting with the Delmer Continuous Casting Furnace ‘Etna’ cD Series, built for consistency, reliability, and precision. Commercially available 1kg graphite mould examples can have external dimensions around 135 × 42 × 32 mm, with cavity dimensions around 115 × 22 × 22 mm. However, dimensions are not universal and should be selected according to the required bar geometry and casting system. Best applications …