Gas delay times or lag times that are short have no predictable influence on wall thickness. For longer gas delay times there will be an increasing solid layer that will form, but this will only prove to inhibit material flow, increase the likelyhood of switchover marks, and limit gas bubble propagation. Long gas delay times can also lead to short shots. The graph below shows how an increase in melt residence time in the mold prior to gas injection can affect the frozen layer thickness. A good way to exploit this cooling affect is with the over-flow cavity technique. Using the over-flow cavity technique the part cavity is completely filled prior to gas injection, the longer the melt remains in the mold the thicker the frozen layer becomes due to cooling against the mold wall.

A study using Makrolon® 2458 polycarbonate confirms that although longer gas delay times do lead to slightly thicker residual wall thickness the increase is not large. The graph below shows less than a 0.40mm increase in wall thickness.