Inside air compressor head sealant?

[Badasssapper67]

Anyone have any luck sealing the interior surface of air compressor crank case and head??
I have a Quincy 325 roc 13 and just got the head, that weighs about 40lbs, totally de-rusted and I want to seal it instead of just let it get all rusty and have that rust clog up the valves.
I wish I was better at technology because I would post pictures. but the inside of the head will require a brush on type paint-epoxy-sealant.
Anyone have any experience doing this?

 

[Bluevista]

Engine builders use that red Glyptal paint to seal the insides of blocks, a compressor isn't much different.
It's single stage and resists oil, don't know how well an epoxy would work inside a compressor with the oil and heat.

 

[Badasssapper67]

Is that Glyptal appplied with a brush or spray paint?