Products tagged with 'stoichiometry'

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Picture for ASH Testing to Confirm Mix Ratio by Volume of Plural Component Applied Material
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ASH Testing to Confirm Mix Ratio by Volume of Plural Component Applied Material

Product Number: 51324-21133-SG
Author: Steve Liebhart
Publication Date: 2024
Epoxy pipe coatings are often used for coating the exterior of buried pipe for means of corrosion protection and other robust performance characteristics they provide. One class of coatings often used for this service are two-component fast curing epoxy products applied using plural component application equipment. With this type of equipment, both paint components are heated and metered separately, until pumped through a static mixer(s) for mixing just prior to being sprayed. What assurance does an applicator have that their equipment is metering and mixing the materials properly? And how can it be determined with accuracy to provide confidence that the material will perform as advertised? After all, good lab practices ensure that the performance properties of the product were evaluated on correctly metered and mixed materials in a lab. There are a handful of quality control tests that can be performed on field applied coatings, but they are most-all a bit crude and only give you a general idea that the coating looks to be on ratio. Depending on the materials being used and how they are formulated, a more sophisticated approach to evaluate the accuracy of the mixed material is to perform ash testing on cured samples prepared prior to or at the same time as material being applied for service. The ash content value of the mixed/cured material can be used to calculate and verify that the required stoichiometric ratio by volume of the two-component mix was achieved. Having a high degree of confidence that the protective coating applied to the pipe was mixed correctly should provide increased confidence it will perform correctly and do its part in preserving the integrity of the pipeline.