Before bonding a strain gage to any surface, the surface has to be prepared, for which standard, well established procedures are prescribed - See bulletin B-127 and B -130 published by Micro Measurements.
However sometimes the prescribed procedures may require some modification due to unexpected or unforeseen problems that can arise, due to reaction between the cleaning chemicals and material of the part on which the strain age is to be bonded.

In this video , we illustrate one such problem that occurs while cleaning certain types of steel components, and requires additional cleaning steps to achieve the required level of cleanliness for strain gage bonding.
One of the preliminary steps in the surface cleaning process is to use M-Prep Conditioner , a mild acidic solution that attacks surface contaminants , but on some types of steel parts, the conditioner produces a layer of white cloudy residue .
It was found that abrading the surface with M-Prep Neutralizer can help remove the cloudy layer and produce a clean surface.