painting a cast iron engine part.

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saltyrob

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Hi Folks,

Recieved new exhaust elbow today which is supplied unpainted.I have a spray can of green Volvo engine paint but would like to know whether to spray the cast iron moulding with a primer or other preparation first. In its unpainted state it looks quite a work of art but its destined for a life in a corrosive enviroment.Also like to mention first class service by Keypart,( just a happy customer).

Many thanks

Rob
 
Not sure if it works on cast iron - I assume so, but I've been mightily impressed with POR 15 on steel recently.

http://www.frost.co.uk/productList.asp?catID=28&frostCat=Rust

Not cheap, but sticks like the proverbial to the bottom of my car. Only time will tell if it's any good but I've heard good reports of it from other classic car people. Failing that, I've used Hammerite on my own boat engine in the past and, if enough coats are applied, it isn't bad. Rust does show through eventually though.
 
Hammerite do a primer for cast iron which I have used with success on the cylinder of a Yanmar underneath the engine paint.
 
Don't paint it, galvanise it.
Quicker, cheaper, and it will last twice/three times as long. They rot from the inside out, where its nigh on impossible to paint.
Cast iron galvanises beautifully!

Up near you is Medway Galvanising-where we send our stuff from down here!
 
I believe the current hi-tech solution is ceramic coating (internal and external). Of course, it will probably cost 4 times the price of the manifold....
 
Just a thought, if it's an exhaust elbow will the heat be a factor when considering the finish? I recall many years ago when "hot rods" were popular, there were various paints or coatings available for manifolds and other hot components such as brake discs etc.
 
saltyrob said:
Hi Folks,

Recieved new exhaust elbow today which is supplied unpainted.I have a spray can of green Volvo engine paint but would like to know whether to spray the cast iron moulding with a primer or other preparation first. In its unpainted state it looks quite a work of art but its destined for a life in a corrosive enviroment.Also like to mention first class service by Keypart,( just a happy customer).

Many thanks

Rob
Click to expand...

Exactly the same component on my Volvo 2002 got two coats of black hammerite (smooth finish) three or four years ago and still looks good as new. The part cost a fortune and they wouldn't throw in any green paint so anything on the engine gets painted black these days.
 
Cast Iron DOES NOT galvanize "beautifully".

3 out of 4 cases turn out very poorly. Its all dependent on the type of cast iron, and the chemistry of CI is very variable from one product to another.
Galvanizing isn't a coating, its an alloying reaction, so the chemistry of the ferrous metal that the zinc is alloying with is very important.
 
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