Another tooling issue that can cause bubbles is a crack in the mold. If a mold cracks to a water line the water can wick to the surface of the mold resulting in bubbles. Cracks in the mold can be obvious with water drips showing on the mold surface. However, there will be cases where the water only shows up after the mold has been closed and clamped up, so when checking for suspected cracks always close the mold to see if the clamp pressure opens up the crack. A short-term fix for a cracked mold is to use a reverse-flow thermolator, as this can affect the cooling capability of the mold. The ultimate fix will be to fix the crack. Be aware during tool design that sharp radii will be more prone to crack.