Exhaust Manifold Color and Best Procedure to Color C3

[Paul C.]

I have a 71 and in the judging manual is only says the exhaust manifolds were cast iron; there should be no orange paint; and the engine was painted with the exhausts off.

1. What color are the exhaust manifolds--natural cast iron color?

2. What is the best treatment to prevent rust and color them or keep the cast iron color?

If have read the threads but they covered C2's and only discussed the method used by J. MacNeish and Caylx which both ersulted in point deductions. There was a mention of soaking them with WD-40 and burning it off.

Thanks Paul

[David H.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

I use Dri-Slide on a rag.

The color will probably be off a little, but after sand blasting the exhaust manifolds to remove rust (and cleaning off the sanding dust), I rubbed them with a rag soaked with Dri-Slide.

Dri-Slide is VERY finely powdered graphite suspended in a light oil. The graphite soaks into the pores on the surface of the exhaust manifold helping to retard rust. The light oil evaporates leaving only the graphite. If the graphite on an area wears off, just touch it up with the rag.

Iron melts around 1500 C, graphite melts around 3600 C, so it is not going to burn off.

I like that it does not look like a coating, the texture of the surface looks new.

Most motorcycle shops carry Dri-Slide, it is used to lubricate throttle and clutch cables.

[Paul C.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

Does Dri-Slide rub off? Several people stated they were docked points when judged if the judge can touch the manifold and it leaves the coloring on their hand.

[Paul C.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

Here's a list of products used by various individuals. Has anyone used any of these before judging and how did you fair in terms of point deductions.

Dri-Slide

Calyx

Hot Stuff

Eastwoods stainless steel coating

Previously mentioned WD 40

Seymour 1200 Cast Blast

[Jeffrey S.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

Paul:
I have used Calyx on my '69 for years and it looks great for anything but NCRS judging. Judges have said many times on this board that they would rather see rust on the exhaust manuals than any preparation. In many cases the car was delivered to the customer with rust already on them after running the engine for a very short time. I would bet that if the manifolds were de-rusted and reinstalled without any treatment and allowed to flash rust, no points would be lost at judging. I personally prefer to have the manifolds treated with the Calyx for everything but judging because I think it looks nicer than naturally occurring rust. Just my opinion and I hope some knowledgable judges chime in.
Jeff

[Paul C.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

Another procedure is using Motomaster Dry Graphite. Paint it on, looks great, and doesn't rub off. Anyone used this or know where to buy some.
Thanks

[Jeff S.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

Paul

Exhaust manifolds are gray iron casting. Their natural, "as cast" color comes largely from the free graphite flakes in their microstructure, but doesn't last long in an underhood & on-the-road environment.

Without regard to Chevy orange overspray & other such originality stuff, I prefer to use high temperature graphite lube on a bead blasted manifold rather than the paints, shoe-polish-like pastes or $200 coating treatments. Sprayon 0204 is one example. It has a very fast evaporating carrier (5-10 seconds) and the graphite pigments sink right into the casting once it's cleaned and properly prepared. You cannot expect good results with this technique by leaving the manifolds on the engine and giving them a token cleaning with a wire brush. After blasting, they must be thoroughly blown with compressed air to remove the glass debris, then wiped with MEK or lacquer thinner before spraying.

http://www.qualichem.ca/item.asp?CatName=Chemicals&CatIdNum=2&SubCatIdNum=20&SubCatName=Lubricants&ProductIdNum=121

You cannot find graphite lube at a FLAPS, since it is an industrial product. McMaster-Carr and other such place will have it for about $4-5/can.

To really get a "first-day" look, buff the manifold lightly with a rolled up piece of newspaper (graphite in printers ink) after a couple light coats of the 0204. That will knock down the lube coating slightly on the high spots of the sand-cast textured surface. The lube will not rub off on the hand. No need to "cure" and no smell at first firing.

Picture below is after 4 seasons of use.

[Paul C.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

I'm going to try graphite. I'll let you know how it works and looks. It is cheap, doesn't rub off, looks great, and is easy to apply.

Paul

[Paul C.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

Used dry graphite in a spray can. Sprayed it into a cup and then painted it on the exhaust manifolds. Finished yesterday--they look great and it doesn't rub off.

Paul

[Gary V.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

What is the preferred blast media to use on exhaust manifolds ? Glass ?
Mine have old VHT white paint on them.

Viz

[Paul C.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

Use the dry graphite. It looks great-like original; a can of graphite is cheap and will last you a lifetime; and doesn't ruboff once it gets hot. Tried other products and it wears off. Graphite may eventually wear off but it is so cheap and easy to apply--who cares.

Paul

[Jeff S.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

What is the preferred blast media to use on exhaust manifolds ? Glass ?
Mine have old VHT white paint on them.

Viz

Gary

Glass bead at about 50 psi; blow dust/debris away with compressed air. Wipe manifolds with fast evaporating solvent such as lacquer thinner, then quickly apply the graphite lube from the rattle can. I use two medium coats, and buff very lightly with rolled up newsprint to knock down a bit.

[Greg H.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

Paul

Exhaust manifolds are gray iron casting. Their natural, "as cast" color comes largely from the free graphite flakes in their microstructure, but doesn't last long in an underhood & on-the-road environment.

Without regard to Chevy orange overspray & other such originality stuff, I prefer to use high temperature graphite lube on a bead blasted manifold rather than the paints, shoe-polish-like pastes or $200 coating treatments. Sprayon 0204 is one example. It has a very fast evaporating carrier (5-10 seconds) and the graphite pigments sink right into the casting once it's cleaned and properly prepared. You cannot expect good results with this technique by leaving the manifolds on the engine and giving them a token cleaning with a wire brush. After blasting, they must be thoroughly blown with compressed air to remove the glass debris, then wiped with MEK or lacquer thinner before spraying.

http://www.qualichem.ca/item.asp?CatName=Chemicals&CatIdNum=2&SubCatIdNum=20&SubCatName=Lubricants&ProductIdNum=121

You cannot find graphite lube at a FLAPS, since it is an industrial product. McMaster-Carr and other such place will have it for about $4-5/can.

To really get a "first-day" look, buff the manifold lightly with a rolled up piece of newspaper (graphite in printers ink) after a couple light coats of the 0204. That will knock down the lube coating slightly on the high spots of the sand-cast textured surface. The lube will not rub off on the hand. No need to "cure" and no smell at first firing.

Picture below is after 4 seasons of use.

Jeff,

I just used this procedure this week. Thanks for the good tip. I have a couple questions.

First, I might have missed a spot and the next day I had some surface rust. I wiped it down with lacquer thinner and re-applied to that spot. It seems to have held, but should I expect it to maintain?

Second, have you gotten yours wet in the four years? I now have to do some heavy cleaning on my engine, maybe should have done so first, but it will get them wet and maybe some engine degreaser. What should I expect after doing this?

Thanks,
Greg

[Jeff S.]

Re: Exhaust Manifold Color and Best Procedure to Color C3

Greg

I have never exposed my manifolds to water or to engine cleaning agents. I'd be surprised if they'd survive under those conditions. Perhaps you could score an old manifold or a scrap piece of cast iron and use that as a test article before going after your engine?

The graphite has no appreciable thickness like a paint ... it is more of a tint absorbed into the natural surface porosities present in a sand casting. I have never experienced any rust, and my manifolds still look as good as the day I installed them. The key is thorough and careful preparation in the manner suggested in my previous post.

Good luck -- let me know how you make out.

Jeff