Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to cast metal [title] Get a 2-piece mold frame. [step] To successfully cast metal, you'll first need to acquire a mold frame (also known as a mold flask) made of wood, iron, or a similarly solid material. Make sure the frame comes in 2 parts and is large enough to hold the object you want to cast.

Ending1: [title] Drill holes for the bottom of the frame. [step] Make sure to drill through the wood like the mouth of a hammer [title] Cut any thin pieces off the frame. Ending2: [substeps] Look for mold frames online or from specialty metal supply stores. As long as it is sturdy, the specific material used to make your mold frame does not matter. Ending3: [substeps] Use 3 full coats of cold metal paste, such as lewis sal, instead of steel paste. Place your mold frame on a flat, dry surface. Ending4: This frame will prevent the object from falling apart when you cast iron objects, and it will give the object some extra room to expand at an angle. [substeps] You could purchase pre-assembled or premixed casts from most home improvement stores.

Answer format: ending1/ending2/ending3/ending4