The Importance Of Using Mock-Ups
Mock-ups (or test-patches) are an invaluable tool in the paint and coatings industry for keeping paint projects on time and on budget.
They are sample patches applied either to sample panels or directly onto the substrate in a less visible location before the actual coating work begins. They applied using the same materials, techniques, and personnel that will be used on the final project.
The purpose of this is to assess the final result of the coating and determine any potential coatings failures before the entire painting project is undertaken.
A mock-up also sets the standard for balance of the project.
Mock-ups on conventional concrete surfaces
On conventional concrete surfaces, mock-ups are a useful tool for testing the effectiveness of surface preparation as well for determining how the specified system will perform.
This is especially important with the increasing use of fly ash concrete. The usual specified water-based alkali-resistant primer for the first coat of the system may fail when applied to fly ash concrete.
This failure is thought to occur because the fly ash is composed from coal. Coal is essentially the same product as oil, so the fly ash may impart oily characteristics into the concrete.
In theory, abrasive blasting could create a profile with sufficient tooth for the water-based primer to adhere where fly ash has been used, but the suspected oily residue could still be present, so a mock-up would be imperative. Additionally, if the project is an interior project abrasive blasting would be prohibited.
To date, solvent-based bonding primers have shown to be effective as a first coat solution for fly ash concrete surfaces, however, it must be noted that concrete is highly alkaline, so solvent-based primers without alkali-resistant properties should not be used.
Correcting any issues that may lead to coatings failure with a test-patch is far less costly and time-consuming than corrections made after large-scale coatings application has commenced.
Wide-scale coatings failure can be avoided by using a mock-up on a small section of the project before large-scale work commenced.
Products tested by MPI are listed in the MPI Approved Products List (APL) under the relevant standard #. Look out for the MPI Approved Product Label on paint cans!
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