The amount of flux that can be applied is limited by the behaviour of the liquid flux.
If a liquid layer becomes too thick the liquid will start to form droplets that will drain off from the wetted surface. Due to this mechanism the application of more liquid will not help to apply a thicker layer.
This mechanism may cause a problem in case more flux is needed for the process than the amount that will be left on the fluxed board.
If the flux amount is not sufficient this can affect the result of the following solder process.
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