In the present work, the method of response surfaces was employed for the purpose of drawing up a mathematical model for the calculation (forecasting) of the thickness of a flame sprayed coating of powdered aluminium on S235JR steel. Experimental work was conducted according to a full central composite design at three levels. The thickness of the coatings made with combinations of input parameters of the procedure according to the experiment plan mentioned was measured in line with the ISO 2064 standard. A mathematical model was derived describing the dependence of the experimentally obtained thickness values on the input parameters of the procedure. The possibility of analysing the influence of the parameters upon the thickness for a certain combination of input parameters has been presented with the use of perturbation plots.