fig1 illustrates a sectional view of an axial flow , turbo fan gas turbine engine 10 which comprises of a compressor section 14 , a combustion section 16 , a turbine section 18 , and a fan 30 . the turbine has rotating blades 22 which are fixed to rotors 28 which rotate about the centerline 12 . in addition the turbine 18 has vanes 20 , which remain fixed with respect to the blades 22 . similarly , the compressor 14 has vanes 26 , and rotating blades 24 connected to a rotor 28 which rotates about the centerline 12 . fig2 a shows a perspective view of vanes 26 . as shown , the vanes 26 are curved and nested within each other . given such a closely - spaced orientation , it is difficult to apply a mask to the surfaces . fig2 b shows the limitations of the prior art apparatus 32 for coating airfoils 62 such as the vanes 26 of a compressor 14 . the prior art apparatus 32 can only partially mask section 34 of two airfoils 62 of relatively complex geometry in series . the remainder of the airfoils 62 remain unmasked , as seen by sections 54 and 56 , since the prior art apparatus 32 cannot reach around the curved surfaces due to its existing geometry . fig2 c shows the spray apparatus 36 of the disclosure which can fully mask 34 the complex geometry of the airfoils 62 in series . in contrast to fig2 a , the entire surface of the airfoils 62 is masked due to the spray apparatus &# 39 ; s ability to rotate and translate about the axis 64 . the spray apparatus may be configured to rotate and translate simultaneously , though the steps of rotating and translating the spray apparatus may be performed separately or in series . fig2 d shows the spray apparatus 36 of the disclosure as in fig2 c in a secondary orientation . in this second orientation , the apparatus 36 has been rotated and translated about the vertical axis 64 . fig3 a shows a side view of the spray apparatus 36 described in this disclosure . the apparatus 36 is rotatably attached to an existing spraying machine 70 and connected to the supply of masking material 72 and an air tank 74 by adapter 38 . the supply of masking material 72 and the air tank 74 may be associated with an actuator capable of propelling masking material 72 through the channel 40 , for example , while concurrently passing air through air channels 60 . alternatively , the supply of masking material 72 and the air tank 74 may be provided with separate , individual actuators capable of such concurrent operation . the adapter 38 is connected to a longer second portion 42 of the apparatus , which is of length d 1 . the second portion 42 is connected to a first portion 44 , which is of length d 2 , and is at an angle 50 from the centerline of the apparatus 48 . in this embodiment , the angle 50 is approximately 45 ° and the ratio of d 1 to d 2 is substantially equal to 2 : 1 . in other embodiments , the angle 50 can be between 35 ° and 145 °, and the ratio of d 1 to d 2 can be approximately 2 : 1 . the spray head 46 is secured to the termination of the first portion 44 . additionally , the at least one channel 40 is secured and congruent to both the first portion 44 and second portion 42 of the apparatus 36 . fig3 b shows a section view of the spray apparatus 36 taken from section a . the first portion 44 is surrounded by air channels 60 . in this example there are two air channels 60 , however in another embodiment there may be any number of air channels . fig4 illustrates the coating process that follows the masking process . the airfoils 62 have been previously coated with the masking material 34 and is then sprayed with the coating material 76 which has been heated in a plasma flame and accelerated at the airfoils 62 at a high velocity . during this process , the masking material 34 protects the coating 78 from directly contacting the airfoils . fig5 shows an outline of the process described in this application . first , the uv masking material is atomized at step 80 . next , at step 82 , the atomized uv masking material is sprayed through the spray head , and then the airfoils ( e . g ., the articles or substrates ) are covered with the atomized uv masking material at step 84 . at step 86 the coating material is heated in a plasma flame , and is subsequently accelerated onto , and deposited onto , the masked airfoils as represented at step 88 . further , as represented at step 90 , the atomized uv masking material may be removed from the airfoils through a heat treating process without detrimental effect to the coating material deposited in step 88 . that is , the heat treating process removes the uv masking material without harming or removing the coating material . in one example , the temperatures associated with the heat treating process are no less than 600 ° f . although an embodiment has been disclosed , a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure . for this reason , the following claims should be studied to determine their true scope and content .