I also use west systems epoxy to close and seal the cowling.
After that, I paint on a couple coats of Diamond Brite aluminum paint.
It creates a nice oil and fuel proof surface and since it has a high aluminum pigment content, it also acts as a heat shield.
On my last RV8, I didnít install the foil heat shield and saw no adverse effects due to heat inside the cowling.
RV6, RV8 (2), RV12 & RV3 about 2/3 done.
A&P, Tech Counselor & Flight Advisor