Miniatures are cast in two- or multi-part moulds which leave noticeable mould lines where the sections of the mould are joined during the casting process. Painting accentuates mould lines, which is why mould lines need to be removed before a miniatures is primed and painted.
Mould lines may be filed, sanded, cut, or scraped off, depending on the material the miniature was cast in.
- Soft plastic miniatures may be cleaned by carefully lifting the mould line off with a very sharp scalpel blade. However, even the sharpest blade will quickly lose its edge, making it more and more difficult to catch and remove the mould line. Working with a duller blade, the soft plastic will be torn off, rather than cut, leaving frayed material on the figure which can be even more difficult to remove than the original mould line. Spent scalpel blades may be sharpened with a whetstone. Another, easier method is to use moderate heat to melt mould lines on soft plastic miniatures. Visit YouTube to view our video tutorial on the subject: Removing Mould Lines from 1:72 Scale Plastic Miniatures.
- Small miniatures cast from a relatively hard metal or plastic are typically cleaned by scraping the mould line with a scalpel blade, because there are so many tiny spaces which only the tip of a scalpel blade can get into.
- Large miniatures cast from a tin/bismut alloy are best cleaned with a needle file. The mould line on a large figure is easy to reach with a needle file even in the smallest spaces like the bend of an arm, and the alloy is hard enough that it does not clog the file.
- Miniatures cast from lead or a relatively soft lead/tin alloy may be cleaned simply by scraping the mould line off with scalpel blade or a dedicated mould line remover. Filing or sanding toxic materials like lead is a very bad idea, because the workspace and its surroundings are sure to be contaminated with dangerous lead dust. Note that exposed skin is permeable to poisonous lead! Wear gloves, do not eat, drink, or smoke while handling lead. Consider using lead-free alloys if you are casting your own miniatures.