This has been shown in several studies on this topic to be LEASE effective type of heat shielding material. Other more effective sources include a water-soluble gel or a ceramic-based nonwoven material. Whatever the type of heat shielding material used to protect neighboring devices during reflow, their use is important to protecting devices from excessive heat which damage the devices.
In order to run a complete profile, the PCB should be adequately supported. This is especially true of there are “imbalanced” copper section of the board or in cases where very thin.032″ thick boards are being reflowed.