Editing Casting (section)

==Imperfections and Dangly Bits==
There are three major side effects which can occur during the casting process: '''vents''', '''flash''', and '''mould lines'''. Vents are the dangly pieces on a metal or resin model that you can quickly nip off with a sharp knife (or a simple twist).  Vents exist because holes are intentionally made in the mould to allow air to escape during the injection process, and excess material to overflow safely.  Flash occurs when the casting material squeezes between the mould's halves, leaving a paper-thin plane of material on the model, often bridging intentional gaps in the finished piece.  Mould lines occur when the two halves of the mould aren't perfectly aligned before casting. In some cases, they're subtle and easy to file down, while some can be so bad the model looks like one face has jumped half a scale meter to one side without informing the other face.

There's really no excuse for bad mould lines on metal models passing quality control, when the models can simply be melted down and recast.  Resin, on the other hand, cannot be recycled in the same fashion, so resin casters need to hold themselves to a higher standard of quality ([[Finecast|Quality, you say?]]).  Luckily, major model retailers have largely eliminated horrendous mould lines in recent years.

[https://blog.mrt-castings.co.uk/blog/sprues-flash-and-runners-explained Here is a good resource] on imperfections in the casting process.