Porcelain Exhaust Manifold Restoration - Cap's Coatings

[J. Russo]

I am considering estimates for my exhaust Manifolds on my 1941 Cadillac. I've seen several posts about Independence Porcelain Enamel and Prairie Porcelain.

Has anyone had any experience with Cap's Coatings in Fresno, CA? I haven't seen any posts related to them. I have an estimate from Cap's and Pairie. Will need to wait until next week for Independence as they seem to be off until after the new year.

I'd appreciate any info on other companies I haven't mentioned if available.

Thanks

[79 Eldorado]

Hi John,
Is the coating you are referring to something like the ceramic-metallic coating sometimes offered on headers? I had some exhaust manifolds coated by Jet-Hot with their version of ceramic-metallic and I could offer some comments. I also coated an intake manifold myself with what was a brush on option; after requiring a bake cycle. I have no experience with the coater you mentioned specifically.

Regarding a vendor coating: One thing I think I would do differently is I would likely go for the polished option. I selected the matte finish because I basically wanted to keep the cast iron look of a stock exhaust manifold. The matte finish is however a lighter grey (doesn't look like as cast) and typically a polished finish will have a little better corrosion resistance simply due to the surface. I'm making the statement despite that the car never sees winter.

One disclaimer Jet-Hot was making at the time is they wouldn't guarantee the results on used parts but their wording even made it sound like they wouldn't on new parts. I wish I still had the exact wording because the used part thing was written as an exception and after reading the entire statement it left me thinking "ok then what do they cover?". The comment had something to do with how clean the surface prep would be able to make the part.

The coating I applied myself wasn't bad but I was using it to further enhance the overall coating durability. I painted over the coating I applied with high temp paint made for motors. The area which had the most trouble was near the base of the EGR. The paint eventually burned off and you could see some spots of corrosion coming through the self-applied and baked ceramic metallic coating.

My opinion is stainless would be the best but not everything can be made of stainless so the ceramic metallic coating option is, as I know, the next "best" option even though I'm not certain how closely I would score nr2 to the best.

Scott

[LaSalle5019]

I rebuilt/restored my engine last year and had Independence Porcelain restore my manifolds to original gloss black porcelain. It was absolutely gorgeous.....until my first drive. During initial engine runs and break-in I had no issues but once I started making some power about 30% of the manifold bubbled and after the next few heat cycles much of the porcelain had popped off. It’s about 40% gone currently.

I was rather upset and Independence offered to re-coat them. After doing a bit more research, I have come to the conclusion that porcelain over new cast iron is slightly durable but over used/aged cast iron it is not very good. I plan to remove them this winter and send them out to Jet-Hot to get ceramic coated in their highest gloss option which is a satin sheen. It won’t look original nor have that beautiful look with new porcelain but they’ll look a lot better than rusty cast iron. If I had any confidence that I would have different results with porcelain, I would be glad to have Independence re-coat them for free and save the cost of Jet-Hot but I don’t feel like going through this process multiple times.
Scott

[J. Russo]

I included the link to Cap's Coatings below. I don't know the exact terminology, but from what I understand my '41 Cadillac has porcelain exhaust manifolds. I talked with the manager at Cap's Coatings and he said they make them like new as long as they aren't too severely pitted or cracked. He also said they have someone that polishes the manifolds for them. The cost is approximately $800 with the polished option. He also said their product can take up to 1300 degree heat.

My biggest fear is having everything fall apart after paying all that money. I guess it is hit or miss with some of the vendors that do this work. I've seen positive and negative reviews on this forum. I hadn't heard of Jet. I'll check them out.

https://www.capspowdercoating.com/automotiveservices.html

[35-709]

FWIW, my 472 headers made by Sanderson were coated by Jet-Hot when new and still look good after 30,000 miles and 10 years.