Casting Fault Finding Chart

Metal is not flowing into all parts
  • No talcum powder. The mould needs a thin coat which helps air to escape.
  • Too much talcum powder is blocking the details.
  • Metal not hot enough. Test temperature with a match.
  • Mould needs an airvent. Make a hole right through mould half in the missing part with a 1-1, 5mm drill bit or a yawl. You can also make a very small channel from the missing part of the top of the mould. This enables air to escape more easily from the mould cavity allowing the metal to flow into all parts.
  • Use Modelmetal. No other metal casts as well.
  • Do not use a vise for cllamping the mould, because it will lock the air into the mould.
  • Use Prince August Clamps or rubber bands.
  • Use Prince August talcum. Not all talcum powders are suitable.
  • Dry the talcum powder in an oven. Damp talcum powder can cause some problems.
  • Pour the metal to the top of the mould to get full gravity pressure.
  • Tap the mould to shake down the metal.
  • Walm the mould in a domestic oven. Use a moderate tempreture (60 degrees C) and leave the moulds in for at least half an hour.
Metal not melting
  • Use a gas or electric cooker on high until metal is molten, then reduce heat.
  • Do not try to melt the talcum powder; melt the badge or bar.
Smoke coming from ladle
  • The ladle is covered with a rust protector which will burn off for the first five minutes. No action necessary.
  • You have left the ladle in a pot of molten metal. Pick out the ladle with a pair of pliers, as the whole ladle may be hot. You may have melted off the handle. Don't leave the ladle in molten metal.
Smoke coming from mould while pouring.
  • Metal too hot. Melt more metal to cool and, check temperature with match.
  • No talcum powder on mould. Powder mould.
Flash on casting.
  • Mould not clamped right. Use one one clamp with pressure point in the centre or two clamps on each side.
  • Mould too hot in the centre. Leave mould to allow heat to spread evenly.
Mould leaks
  • Mould not clamped right. Use one clamp with pressure point in the centre or two clamps at each side. For certain big moulds it might be necessary to use four clamps.
  • Check if there is a gap between mould halves. When opening the mould you might have bent the mould getting a casting out. Rectify this by bending halves towards each other.
  • You have not put the hardboard sides on the mould. This is essential to apply even pressure.
  • Put a clamp over the leaking point.
  • If above actions don't help, do the following: Where the metal is leaking from the figure, cut a v-shaped airvent going to the top of the mould with a hobby knife. It stops the escaping air from parting the moulds while pouring the metal.
Mould exploding
  • Do not cool mould or metal with water. Even a small amount of dampness could be dangerous.
Part of the figure is buried in the mould half.
  • It is sometimes necessary to cut a path to allow a part of a complex figure to be released from the mould half. Each mould is unique and will have it's unique parting line where the mould making tool has found the balancing point between the mould halves as the rubber vulcanises.