Foundry

The Foundry is a high-tier crafting building that casts molten metals and directly produces many metal-based items more efficiently than conventional furnaces or assemblers. It accepts ore plus calcite to produce molten iron or molten copper, accepts molten metal to cast plates and items, and includes a range of specialized recipes (including some unique to the Vulcanus surface). The Foundry has a built-in crafting speed and a large inherent productivity bonus that makes its outputs far greater per input than the equivalent furnace/assembler chains in many cases.

The Foundry provides twenty unique recipes (not counting the recipe that produces another Foundry). Some Vulcanus-only recipes include producing molten metals from lava, and high-end items such as tungsten-related products, certain science packs, and advanced belt/splitter items. Usable on any surface are the basic molten-metal recipes (molten iron, molten copper), casting recipes (iron plate, copper plate, steel plate, iron gear wheel, iron stick, copper cable, pipe, pipe-to-ground, low density structure, tungsten plate), and conversion recipes such as concrete-from-molten-iron. Several belt and splitter recipes (transport, fast, express tiers and their underground/splitter variants) are also available as non-unique recipes that the Foundry can craft when their technologies are researched.

The Foundry’s most important mechanical traits are its crafting speed and its built-in +50% productivity bonus (the wiki commonly describes this as +150% productivity in total output with the Foundry’s default settings). Because this productivity bonus also applies to the molten-iron and molten-copper recipes, the effective metal yield per unit of ore is substantially higher when using a Foundry: for example, with the Foundry’s default bonuses a given quantity of ore produces 1.5× the molten metal compared to the base conversion, which propagates through casting recipes and inflates final output relative to smelting-only chains. As a result many Foundry recipes are more resource-efficient than making the same items in furnaces or assemblers.

• Use the Foundry to centralize metal casting where input calcite and ore are plentiful; casting plates and many end items directly inside the Foundry often reduces ore requirement compared to conventional smelting + assembly chains.
• Because the Foundry’s productivity bonus applies to molten-metal production, chains that feed molten metal into the Foundry for direct casting maximize efficiency. Feeding Foundry-cast plates into other machines removes the Foundry’s direct casting advantage only if the downstream machine can supply enough additional productivity to offset the difference.
• Alternate production chains remain viable: casting plates in the Foundry and then refining or assembling them elsewhere can sometimes beat direct casting for specific outputs (for instance steel by casting iron plates and smelting them in an electric furnace, or producing copper wire by casting copper plates then assembling). These alternate chains trade the Foundry’s simpler, highly productive single-step recipes for potentially greater overall efficiency at the cost of more machines and higher module/technology investment.
• The Foundry can accept productivity modules, and some recipes (notably the concrete-from-molten-iron recipe) can benefit from productivity modules even when their conventional furnace/assembler counterparts cannot.
• Research gates apply to certain high-tier Foundry recipes: tungsten plate, turbo belt/splitter/underground items, and several express/fast belt recipes require the corresponding logistics or tungsten research to craft in the Foundry.
• On Vulcanus, the Foundry gains access to unique lava-based recipes (molten metal from lava, specialized items) not usable elsewhere; place Foundries on appropriate surfaces when exploiting those local resources.

Plan Foundry deployment around calcite/ore throughput and the recipes you wish to prioritize. For maximum resource efficiency, favor Foundry casting for plates and direct-cast items when you lack sufficient high-level module or research investment in downstream machines; consider secondary assembly or smelting only when those machines’ aggregate productivity and module capacity overcome the Foundry’s native advantage.