Recommendations for Best High Temp Paint (1 Viewer)

[88Retired62]

Looking for the best “tried & true” high temp paint before reinstalling my rebuilt cylinder head.

 

[cps432]

An enamel paint will work well. But with any kind of painting on metal it’s all about your prep work. You can’t expect a can of ceramic header paint marketed to withstand 1,000 degree temps to do anything if you apply it to rusty metal, oily metal, or metal that is not properly treated to take paint.

A good practice is to have your cast iron dipped and treated by the machine shop so it’s had as much of the oil pulled from the pores in the iron as possible.

If you’re not doing all that then you need to chemically/physically remove all the old paint. Use a rust converter/steel prep such as OSPHO or muriatic acid carefully so as not to affect your mating surfaces. That’s a whole process in itself but is kind of necessary for the paint to actually stick the way it did at the factory.

Then just before you paint you’ll want to wipe down with acetone and then hit the bock with a blow torch to draw any moisture to the surface. Any oils that show up will need to be dissolved and dealt with before paint. Do this until no moisture shows up when you apply flame to the iron.

With the block completely dry and free of oils and the metal prepped to take enamel paint, you can shoot plain Jain Rustoleum and it will work well. Best to use a primer.

You can dilute Rustoleum with acetone or lacquer thinner depending on the ambient temperatures. Being that it’s an alkyl enamel it can take an ENAMEL hardener to improve durability and strength. Don’t try to use a urethane hardener with Rustoleum. Gotta be an enamel type hardener.

As for your mix ratios, do some research on thinning Rustoleum for a spray gun with hardener. There’s lots of ideas on what works best but I think it’s going to be different depending on your climate and equipment.

If you don’t want to do all of that, by all means don’t. It’s a LOT of work and some of the chemicals are dangerous and nasty. But that’s what you need to do no matter what brand of paint you’re using if you want the paint to stick in tough places like around the exhaust manifolds. Even then, the factory enamel didn’t last forever.

If you buy POR15 in a kit they sell all the metal prep chemicals and suggest this same basic process for their product. It comes down to chemistry.

 

[OSS]

Motor Coater Engine Paint - Engine Paint - Caliper Paint

www.kbs-coatings.com

This stuff is excellent. I used it on my cylinder head. Just brushed it on. It levels out and cures smooth. Really nice paint.

Be careful with it though since it uses isocyanate solvent. Have good ventilation.

But even regular spray on (or brush on) rustoleum works fine too. I used that in the past also on the cylinder head with good results.

 

[BurntToast]

An enamel paint will work well. But with any kind of painting on metal it’s all about your prep work. You can’t expect a can of ceramic header paint marketed to withstand 1,000 degree temps to do anything if you apply it to rusty metal, oily metal, or metal that is not properly treated to take paint.

A good practice is to have your cast iron dipped and treated by the machine shop so it’s had as much of the oil pulled from the pores in the iron as possible.

If you’re not doing all that then you need to chemically/physically remove all the old paint. Use a rust converter/steel prep such as OSPHO or muriatic acid carefully so as not to affect your mating surfaces. That’s a whole process in itself but is kind of necessary for the paint to actually stick the way it did at the factory.

Then just before you paint you’ll want to wipe down with acetone and then hit the bock with a blow torch to draw any moisture to the surface. Any oils that show up will need to be dissolved and dealt with before paint. Do this until no moisture shows up when you apply flame to the iron.

With the block completely dry and free of oils and the metal prepped to take enamel paint, you can shoot plain Jain Rustoleum and it will work well. Best to use a primer.

You can dilute Rustoleum with acetone or lacquer thinner depending on the ambient temperatures. Being that it’s an alkyl enamel it can take an ENAMEL hardener to improve durability and strength. Don’t try to use a urethane hardener with Rustoleum. Gotta be an enamel type hardener.

As for your mix ratios, do some research on thinning Rustoleum for a spray gun with hardener. There’s lots of ideas on what works best but I think it’s going to be different depending on your climate and equipment.

If you don’t want to do all of that, by all means don’t. It’s a LOT of work and some of the chemicals are dangerous and nasty. But that’s what you need to do no matter what brand of paint you’re using if you want the paint to stick in tough places like around the exhaust manifolds. Even then, the factory enamel didn’t last forever.

If you buy POR15 in a kit they sell all the metal prep chemicals and suggest this same basic process for their product. It comes down to chemistry.

This 100%, all in the prep

 

[OSS]

Also - I repainted my cylinder head after it was already installed on the block. It’s easy.

 

[Eurasiaoverland]

Motor Coater Engine Paint - Engine Paint - Caliper Paint

www.kbs-coatings.com

This stuff is excellent. I used it on my cylinder head. Just brushed it on. It levels out and cures smooth. Really nice paint.

Be careful with it though since it uses isocyanate solvent. Have good ventilation.

But even regular spray on (or brush on) rustoleum works fine too. I used that in the past also on the cylinder head with good results.

Isocyanates are in the hardener, not the solvent. They are only a hazard if sprayed, brushing on does not represent a hazard, but wear gloves.