Manifold coating - still failing

(Paul Breen pay palled it) #1

Hi Gents, when last the cyl head was off I scarified the Series 1 exhaust manifolds, rattle can sprayed with “extreme heat, with ceramic” product, cured in the barbecue per instructions (temp and duration). Fitted up and ran the car - within weeks had developed small curly flakes - damn! Had a couple of days at the mother-in-law’s and found a new can of pot belly stove black. Followed the instructions and drove back to Sydney. Opened the bonnet to find per picture - the only difference - curly flakes are bigger. Another fail! Has anyone had success with this problem? I note that my Mk2 has a light grey coating that is just perfect :confused:.


I think its what they call a sacrificial coating!

I’ve tried allsorts - including stove paint and spay on ceramics. Nothing lasts. Given up. Have found one NOS rear manifold in perfect condition - now looking for the other.


(Paul Wigton) #3

Other than JetHotting, it appears the only viable, but dull, method that is successful is old-fashioned stove black.

(Rob Reilly) #4

Here is an example of the Jet-Hot treatment on my Mark V, cost about $200.

Jet-Hot is popular with street rodders.

Here is an example of the Prairie Porcelain treatment on my XK120, cost about $450. He is a one man shop in Minnesota. Another competitor is Independence Porcelain in Missouri and there is a third in California.
I thoroughly removed all rust with sanding discs before sending them to Prairie.
Porcelain is popular with XK owners, but they caution you not to let it get splashed with a lot of rain water when hot.


I just love the gloss black look - so original.

I guess you get what you pay for!


(Bob Faster) #6

here is Jet Hot Satin 1300. I did not sand or do anything prior to sending them off ( wish I had now). They sandblasted off what little porcelain was left and coated them. they still look as good as new after several years and even getting wet in the rain. was about $350 with shipping both ways.

Bob F

(Paul Breen pay palled it) #7

Well, perhaps that’s why the Mk 2 is so good - looks the same surface as your MkV! Thanks to my PO. We have Jet Hot here as well - some of our club members also swear by Melbourne Enamelling. Thanks to all for responses - perhaps a “paint on” isn’t really doable. Paul

(Michael Garcia) #8

try starting it for a few
then shutting it off…
allowing it to idle longer…
maybe give it a little gas…
for 28 days
allow it to cure

(Paul Breen pay palled it) #9

Any particular product, Michael?

(Michael Garcia) #10

high heat…
2000° f
preping is vital
paint will only stick to a substrate that is sound
if you are looking for a colored finish,
may l suggest
priming it with high heat
then powder coating it…

considered curing the powder coat
on the car, but lighter colors may turn pink…

the process of curing
any paint
per specs of
is also vital
to longetivity

(Michael Garcia) #11

…with a high heat clear coat
in theory
you could sandwich a thin coat of color between two coats of primer and two coats of clear…

lve only used the primer
and black color
it sticks great

wipe it with mineral spirits about ten minutes before you spray it
hang the piece
only handle it with clean rubber gloves
bare hands have oil on them.

hope this helps…

(Paul Breen pay palled it) #12

Thanks. Expect I will reload this as a project in winter. Paul

(cdscds) #13

hello there,

I use a product here in the states called ‘slip plate’
It’s a dry graphite aerosol.

Here is an article about it.

It’s pretty easy to apply.


(Paul M. Novak) #14

Do cast iron exhaust manifolds treated with Slip Plate continue to look good over time? Especially if the car is driven regularly?

I am considering getting a can and trying it on the exhaust manifolds of a 1984 XJ6 Vanden Plas that I am working. The exhaust manifolds are removed from the engine and available for me to try this now.


(Paul Wigton) #15

I used to do this with tubular racing manifolds, but never a cast iron one: you bead blast them, install them, just before firing up the engine, generously coat in ATF.

Start the engine, and wait til the smoke clears!

(Must be done outdoors…!)

It leaves a relatively rustproof surface, with much the same color as the 'Slip Plate"

(Gary Crosby 75 XJ6L, 85 XJ-S, 09 XF Supercharged.) #16

That slip-plate coating sounds similar to the treatment to locomotive smoke boxes. Smoke boxes were painted in a mixture of linseed oil and graphite. Apparently this mixture outlasted any paint on the smoke box as it had no boiler wrapper and saw high heat from flames extending up the flues.



(Frank Andersen) #17

Just remember that the exhaust manifolds may reach red hot temps, Paul - they are not just ‘warm’…

One of the problems is owners preference for particular looks - which may not available with the necessary heat resistance…?

xj6 85 Sov Europe (UK/NZ)

(Andrew Waugh) #18

Has anyone tried Parkerizing an exhaust header?

I use it quite often to blacken fasteners, parts, and jigs - the solution is easy to make (Manganese, Zinc, Phosphoric acid, distilled water and steel wool) and you just hang the (cleaned and degreased) parts in the boiling solution for about 15 min.

I rinse them hot, then dip/wipe them with Ballistol.

(Paul Breen pay palled it) #19

Hi Carl. Thanks for article - will read. In Japan on holidays, cars are a million miles away! Paul

(Paul Wigton) #20

Hmmm… be worth a try.