Ask Dr. Dave
Ask Dr. Dave: Can you use adhesives for bonding plastic plumbing pipes?
Dave Dunn's January 2019 column.
I have seen at least one manufacturer advertising a two-component methyl methacrylate (MMA) adhesive product in a cartridge for the bonding of PVC and CPVC pipes. These adhesives will give good adhesive strength on these substrates. In addition, they have wide acceptance in the building industry for applications such as profile bonding. However, there is a long tradition of using solvent cements for plumbing applications; they perform well and are cost effective. The solvent cements are usually brush applied to the surfaces, and they soften and dissolve some of the plastic (known as “solvent welding”).
The major issue with solvent cements is their high volatile organic compound (VOC) content, which is released during their application to the joints. VOCs can cause smog and indoor air pollution and have negative health effects. In recent years, regulations, mainly promulgated by the state of California, have set limits on the VOC content of the cements; these limits will be lowered even further by 2023
There is a wide range of solvent cements on the market, depending on the pipe materials (typically PVS, CPVC and ABS), which can be mixtures of solvents and thickeners to suit the pipe diameter, different gaps, and bonding dissimilar materials. Also, many solvent cements are certified for potable water applications to NSF61 and also specified in many plumbing codes. There is no doubt that a MMA adhesive may be suitable for large-diameter pipes, where there are large gap filling requirements. In addition, they have a much lower VOC content. However, it is unlikely that one such product will have wide application across a broad spectrum, including certification and specifications. To note the efficacy of cements, I have personally seen solvent cements used to bond PVC tubing in critical medical device manufacturing.
The bottom line is that the MMA adhesives do have limited applications as low-VOC products, but solvent cements will continue to be the major products unless VOC requirements are lowered even more dramatically.
Any views or opinions expressed in this column are those of the author and do not represent those of ASI, its staff, Editorial Advisory Board or BNP Media.
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