How do you unlock the blast furnace for processing metal for tools?

Unlocking the blast furnace in Valheim is a critical step for processing higher-tier metals like black metal and crafting advanced tools and weapons. The blast furnace is an upgraded version of the smelter, designed to handle more advanced materials. To unlock it, you must first progress through the game''s tech tree by defeating bosses, exploring biomes, and gathering specific resources.\n\nTo begin, you must defeat the second boss, The Elder, located in the Black Forest biome. Defeating The Elder grants you the Swamp Key, which allows access to the Sunken Crypts in the Swamp biome. Inside these crypts, you will find scrap iron, a crucial resource for crafting the blast furnace. Scrap iron is used to create iron bars, which are essential for crafting the blast furnace and other advanced items.\n\nOnce you have gathered enough scrap iron, smelt it into iron bars using a smelter. You will need 20 iron bars to craft the blast furnace. Additionally, you will need 5 surtling cores and 10 fine wood. Surtling cores can be found in Burial Chambers in the Black Forest or by defeating Surtlings in the Ashlands biome. Fine wood is obtained by chopping down birch or oak trees in the Meadows or Plains biomes.\n\nAfter gathering the required materials, you can craft the blast furnace at a level 2 or higher workbench. Place the blast furnace near your base, preferably close to your smelter and other crafting stations for efficiency. The blast furnace operates similarly to the smelter but can process black metal scrap and flametal ore, which are essential for crafting end-game gear.\n\nA common challenge players face is locating enough surtling cores. If you are struggling to find them, consider exploring multiple Burial Chambers or farming Surtlings in the Ashlands. Another tip is to ensure your base is well-protected, as the blast furnace and its resources are valuable and may attract enemy raids.\n\nIn summary, unlocking the blast furnace requires defeating The Elder, exploring the Swamp biome for scrap iron, and gathering surtling cores and fine wood. Once crafted, the blast furnace will significantly enhance your ability to process advanced metals and craft powerful tools and weapons. Focus on efficient resource gathering and base defense to maximize your progress.