How do you craft a blast furnace and what does it allow you to smelt?

The blast furnace is a crucial crafting station in Valheim, allowing you to smelt advanced metals like black metal and flametal. To craft a blast furnace, you must first defeat Moder, the fourth boss in the game, to obtain the necessary crafting recipe. Once you have the recipe, you will need the following materials: 20 fine wood, 10 iron, 20 stone, and 5 surtling cores. These materials are gathered from various biomes and enemies, so preparation is key.\n\nFine wood is obtained by chopping down birch or oak trees in the Meadows or Plains biomes. Iron is mined from muddy scrap piles in the Swamp biome, which requires a wishbone (dropped by Bonemass, the third boss) to locate. Stone is abundant and can be gathered from rocks found in any biome. Surtling cores are dropped by surtlings, fiery enemies found in the Ashlands biome or in flame geysers in the Swamp biome. Gathering these materials may require multiple trips, so ensure you have adequate storage and transportation.\n\nOnce you have all the materials, you can craft the blast furnace at a workbench. Place the blast furnace in a secure location, preferably near your other crafting stations for efficiency. The blast furnace requires coal to operate, which can be produced by burning wood in a charcoal kiln or by defeating surtlings. Coal is essential for smelting, so stockpile it in advance to avoid interruptions.\n\nThe blast furnace allows you to smelt black metal scrap and flametal ore into usable bars. Black metal scrap is dropped by fulings, aggressive enemies in the Plains biome, while flametal ore is found in the Ashlands biome. Smelting these materials unlocks advanced crafting recipes, such as black metal weapons and armor, which are essential for surviving late-game challenges. Without a blast furnace, you cannot progress to crafting the best gear in Valheim.\n\nOne common challenge is the difficulty of gathering surtling cores, as surtlings are dangerous and the Ashlands biome is far from the starting area. To mitigate this, focus on flame geysers in the Swamp biome, which spawn surtlings regularly. Use a bow or melee weapon to defeat them safely, and consider building a portal nearby for quick access. Another challenge is transporting heavy materials like iron. Use a cart or longship to carry large quantities, and always bring a pickaxe for mining.\n\nIn summary, the blast furnace is a game-changing crafting station that unlocks advanced metalworking in Valheim. To craft it, gather fine wood, iron, stone, and surtling cores, then build it at a workbench. Use coal to smelt black metal scrap and flametal ore, which are essential for crafting top-tier gear. Plan your resource-gathering trips carefully, and always prioritize safety when exploring dangerous biomes. With a blast furnace, you can take on the toughest challenges Valheim has to offer.\n\nPractical tips: Always carry a portal kit when exploring new biomes to establish a quick escape route. Build your blast furnace near your forge and other crafting stations to streamline production. Stockpile coal and other resources in advance to avoid downtime. Finally, consider building a defensive perimeter around your base to protect your valuable crafting stations from raids.