Casts
Casts are used to turn liquid material from the Smeltery into tool parts in the Tinkers' Construct mod. To make a cast, pour liquid Aluminum Brass, or Gold into a Casting Table ontop of the tool part for the cast you wish to make. The tool part must be stone to make a proper cast.
The cast can now be used to make tool parts directly from the smeltery. Put the desired cast in the Casting Table, then turn the Faucet to let the liquid metal fill the cast. It should take a moment to dry. Each cast is reusable so it is only necessary to make one cast of each part.
Blank Casts are only good for making the Ingot Cast at the Stencil Table. All other parts must be cast directly from pre-existing parts or parts you make of another material, such as stone. You can also resmelt casts by putting them back into the Smeltery.
Casting Update
In the newest version of Tinkers' Construct, you must now create the casts from prefabricated parts. The process is roughly this:
1. Create the stencil for the part that you want at the Stencil Table. With an empty stencil, press next pattern or previous pattern to cycle through the possible patterns in the Stencil Table.
2. Place the stencil on the Part Builder.
3. Place stone into the Part Builder and make a stone part. The stencil will tell you how much material you will need; ex: "Material Cost: 8" requires 8 Stone.
4. Place the stone part onto the Casting Table.
5. Create a cast. Empty the liquid gold or liquid aluminum brass from the Smeltery onto the Casting Table (the part should still be there) by right clicking the faucet. In order for this to work, the gold or aluminum brass must be the first ore in the smeltery, as the smeltery can only release the bottom-most ore. To remove any unwanted ores, you can place a faucet over a basin and right click to drain it.
This will create a part cast, which you can then use as a basis to cast other parts directly from the Smeltery. Simply place the fresh part cast onto the casting table and pour whatever liquid metal you want to use onto the cast.
It's a little more time-consuming to do it this way, but it's also more "honest" to an actual casting process.