Probably in 2011 a compressor I was using couldn't fill the tank because the head gasket was blown. This is Italian made compressor, two cylinder with valve plate - so actually two quite complex gaskets with long narrow strips. Difficult to make properly. I knew a guy spent many hours making new gaskets for it months earlier and I saw many hours go down the drain if I was to attempt to make them. This was Friday evening and I was going to use the weekend to finish a job.
So I took it a part and cleaned the head, cylinders and valve plate very well. Then I used thin layer of red High Temp RTV silicone to seal it. I also sealed the outlet manifold with same method. Let it sit overnight and fired it up the morning after and could use it over the weekend like I planned.
The fun thing: This compressor is still running in the shop. It's set to 10 bars and has 7hp motor. I was using it just last week, and saw the thin red silicone beds around the joints. Just like I left it over 10 years ago. Works fine and no leaks I could detect.
I have done this on few compressors since. But none of them has seen as much use as this one. I consider high temp RTV as good if not better than some original gaskets - based on experience. And I will probably never consider making gaskets for air compressors again - unless the gasket is used to provide clearance.