Correct. In my case i bought 100 ft spool of 1mm mylar, then cut shape to serve two purposes.
1) satisfy UL,coke spill test over HiV to DC open frame enclosed PSU
2) spoiler fold down on intake to create turbulent eddy currents to reach surface of all MOSFETs and ferrite cores.
Then I found 1.5" fans too noisy at full speed so I used LM317 , pot , thermistor epoxied the ferrite core, 1signal transistor bridge amp to drive ADJ and used FR4 waste tabs to use as an insulated nut for self tap nylon screw to chassis.
Then fan was 0 Rpm up to 80W load and gradually increased to 50% speed at full load 40'C ambient from 45 to 50C inside at hot spot.
Total budget I designed for was 2$ including connector for precision fan speed control, 1k/mo
Who knows Al, we may have had connections from my days in Downingtown, Paoli , Rockaway (HP PSU factory) or elsewhere nearby. Its hard to be humble, but I have done a lot.