harleyKmodel

If you use the silver or black high temp paint (I have used both in the past) you will notice you have to break the bond with a copper or plastic hammer next time you split heads... It gives a really good bond/seal...

And this is what happens if you don't check your head bolts often enough on a supercharged engine, our last pass at Bonneville in 2013, one got loose and the flame front went past it melting some alloy in the process:



Patrick

In my opinion, the head should be installed while the paint coating is still sticky. Have everything ready to go and install within a few minutes, depending on the ambient temperature. I would not install one with dry paint unless if the coating turned out to be soft when dry. A coating still sticky would conform and seal much better. Also, I think Copper Coat spray by Permatex would be a better choice. Just my opinion.

I have good experience with VHT Copper Gasket Cement

I have used both aluminum paint and copper based sealant with good results. Now, I buy Sherwin-Williams brand aluminum paint. I let it sit for week or so to allow the solids to settle out. Then, I decant ~2/3 of the oil. The remaining viscous material is carefully applied to the mating surfaces. One does not want the material to get into the combustion chamber or on the valve seats. When the material is tacky (not dry), I attach the heads. So far, this works for me.