College of Engineering
Materials Engineering Department
BS in Materials Engineering
Water side corrosion within copper plumbing can occur due to a wide variety of unwanted circumstances. Through the controlled immersion of six ¾” copper tubing samples with five utilizing a unique industry standard soldering flux, this investigation associates residual flux deposits with the initiation of pitting in copper. Water stagnation in a copper potable water distribution system, typically associated with an infrequently used faucet, is a condition highly prone to copper pitting. A test apparatus designed to produce a partially stagnant flow condition with scheduled electrolyte flushes every 3 days was developed and constructed to contain 6 test samples for a period of 75 days. After the completion of the immersion period, each sample was analyzed. Between the fluxes utilized, 3 conform to industry standard ASTM B813 which contains strict parameters concerning the “flush-ability” and “non-corrosive” nature of the residual flux remaining on the inner wall of copper tubing after soldering. Upon examination of the samples after immersion, it was evident that the most corrosion products formed on the samples which conformed to the standard. The remaining fluxes are petrolatum based and therefore do not meet the water solubility constraints of ASTM B813. This disqualification contradicted the performance of these fluxes upon initial examination. However, utilizing optical microscopy equipment, the most severe corrosion products in terms of their potential to lead to future damage were recognized on those samples containing fluxes which do not conform to ASTM B813.