It is possible to craft a variety of in-game items like consumables or grenades using workbenches located throughout the Commonwealth. As opposed to crafting in Fallout: New Vegas, it is not possible to craft your own ammunition or ammunition subtypes in Fallout 4 in the vanilla game, with the exception of grenades, syringer ammo for the Syringer rifle or Nuka-nukes for the Nuka-nuke launcher from the Nuka-World add-on. Modding is carried out by applying pre-defined components to armor and weapons, like adding lead to armor parts for enhanced radiation resistance or equipping several types of barrels on firearms. Modding or crafting does not generally require schematics, but certain active player perks are affiliated with some types of modding, e.g. Science! for modding energy weapons or Armorer for armor.
The basis for all crafting and modding is the gathering of raw components listed below. Scrapping is commonly required to harvest these materials and can only be done while in "Workshop Mode". Some items will outline in yellow while other items will outline in green while in Workshop mode. This seems to only indicate whether the item is able to be moved and has no other purpose. Green items can be moved while yellow items are fixed in place. None of these items will respawn after scrapping.
The 31 crafting components are the most basic junk items which can be used to craft other items, and cannot be broken down into other items.
Although some instances of the following items exist in the game world, they are more commonly obtained by scrapping other items. Additionally, shipments providing larger quantities can be bought from several vendors and are weightless.
When scrapping other junk items, you will always receive the components specified. However, when scrapping other items such as...
...you will only receive a fraction of the components which were originally used to craft the item. The types and amounts of components received in these cases is determined by two factors: rarity and scrap scalar.
Rarity has four possible values:
Common: these components are always received.
Uncommon: Scrapper rank 1 is required to receive these components.
Rare: Scrapper rank 2 is required to receive these components.
Zero yield: these components are never received - only applies to adhesive and oil.
Additionally, the original amount of components used to craft the item is multiplied by the scrap scalar, rounding down, when determining the amount of components received.
Collapsed buildings, cars, street lamps, almost anything lying about within a workstation area can be scrapped for building materials. While you are in the structures/crafting screen, point your sights towards one of these objects and it will light up. To scrap an item, press the square button for PS4, X for Xbox One or R for PC.
All items in scrapped containers, or attached items will be moved to the workshop's storage, accessible from any crafting station, or from the workbench itself. The exception is locked containers where the contents will be lost.
Scrapping an object such as a table, wooden crate, shelf, etc. will cause any objects on or touching to disappear from the game. Scrap those objects first before scrapping the table, etc.
Scrapping a crafted item when another crafted item is attached, will not scrap both items only the highlighted item is scrapped. The other item will be moved to the workbench.
Movable items located outside the boundaries of a settlement (e.g. the engine under the bridge near sanctuary) can be carried into the settlement and scrapped.