You must make 10,000 bars of metal to get this achievement. Metal bars are made from smelting ore you collect at a forge, and are iron, lead, tin, copper, silver, gold, tungsten, cobalt, palladium, mythril, orichalum, platinum, titanium, or adamantite. A simple forge can be made/crafted or purchased from the merchant. You will need these bars of metal you are smelting to craft various things (especially weapons and tools) to progress in the game. You obtain ore by mining it from the world in the underground. They are typically found in clusters/pockets. The deeper you go, the better ore you find. You dig using a pickaxe, and stronger pickaxes dig faster.
You should get this achievement through natural progression in the game (although it will take a while), but there are a few methods to make it go faster. Unfortunately, there is no progress tracker for this achievement, so you must keep track yourself.QUICK SOLUTION
All smelting is done at a Furnace using various ores.
A (regular) furnace is made at a workbench using 20 stone, 4 wood, and 3 torches. This smelts all the basic metals.
A Hellforge is found in the Underworld, and can be removed using any Hammer of 60% power or higher. You can place this in your base or anywhere you want. A Hellforge can smelt Hellstone in addition to the basic metals.
A Hellforge is required to make a Titanium/Adamantium Forge. This is made from 30 Titanium/Adamatium ore at a Mythril/Orichalum Anvil. The Titanium/Adamantium Forge can smelt ANY metal ore
, effectively replacing the need for any previous Furnace.ORES TO BARS CONVERSION(Regular) Furnace
3 ore --> 1 Bar : Copper, Iron, Tin, Lead, Cobalt, Palladium
4 ore --> 1 Bar : Silver, Tungsten, Gold, Platinum, Demonite, Meteorite, Mythril, OrichalumHellforge
4 Hellstone Ore AND 1 Obsidian --> 1 Hellstone BarTitanium/Adamantium Forge
5 ore --> 1 Bar : Titanium, Adamantium, Chlorophyte