We are painting concrete using an epoxy primer followed by acrylic poyurethane top coat. Total DFT is 300 microns.
We planned to use WFT readings and then as a check random Elcometer destructive DFT tests. We were then told that this sort of DFT scratch test was not to be used and we must use a PosiTector 200 ultrasonic test meter for each coat.
There are 2 things that concern me. Firstly the application of even a small amount of gel to get the reading between coats. Secondly I doubt the accuracy of the instrument. We find about 30% of the readings are not reproduceable.
Does anyone have advice on the standard practice for checking coating thicknesses on concrete surfaces.
We planned to use WFT readings and then as a check random Elcometer destructive DFT tests. We were then told that this sort of DFT scratch test was not to be used and we must use a PosiTector 200 ultrasonic test meter for each coat.
There are 2 things that concern me. Firstly the application of even a small amount of gel to get the reading between coats. Secondly I doubt the accuracy of the instrument. We find about 30% of the readings are not reproduceable.
Does anyone have advice on the standard practice for checking coating thicknesses on concrete surfaces.
