clear powdercoat on aluminum intake?
 

If I clear powdercoat an aluminum intake, will the exhaust crossover discolor?

George

I would expect so--that crossover gets SCREAMING hot when the heat-riser valve is working. It gets nearly as hot with the heat riser valve disabled.

What is the temp limit for the powder-coat powder?

https://nitroplate.com/coatings/nitroplate-satin/


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I would highly recommend Cerakote for your intake. Lots of colors available and very resistant to high heat. Had my intake and ram air exhaust manifolds done this spring., looks great and holding up perfectly. Most powder coasters can apply this product.

Dont think normal ceramic coat is made for high temp, maybe they have a high temp option now? What I use for intakes, other engine parts like valve covers and even aluminum heads is clear engine paint, i use rustoleum but other brands have it too, heard VHT works good too, they are high temp & oil resistant, even resistant to gas if not long term exposure.

It does not yellow or flake off if parts are prepped right, been on my E-heads for 10+ years & looks like the day it was applied. Aluminum doesnt hold heat like iron so engine spray clears & paints last a lot longer than when on iron like how ex ports on iron heads burn off almost any kind of paint.

You can also spray a very thin coat vs thick powder coat that will look better on cast aluminum parts and can help with heat retention from too thick of a powder coat.

My father powder coated his intake years ago and still looks like new but we don't run heat cross overs.

The headers I cerakote myself. Cerakote is ok, it's heat resistant but I don't find it as durable as plain old powder coat. Cerakote scratches pretty easily.

George, look into clear anodizing.

You can anodize an aluminum casting, but it's a challenging process. Not not all alloys are suitable, that and they are often porous.

I've seen some frown on high temperature ceramic coat on intake manifolds stating it holds in heat.
Personally we have experienced no issues with a bright ceramic coating finish on my intakes.

I've never used a satin finish as in the example in my post #2.
However as shown there I agree it's light grey appearance of natural aluminium has the potential to retain the new part look.

If one has a concern for holding in heat here is another potential option I found on the internet. Have it Vapor blasted.
The author states it anneals the pores in the aluminum and resists corrosion. The finish is smooth to the touch, not like sandblasting, and looks fantastic.
To clean he just sprays some WD40 on a rag (not a lot) and wipes it down when it is dirty.

Attached here is a part finished with this method:

https://cimg7.ibsrv.net/gimg/www.cor...03f0140c77.jpg



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I painted my intake with the natural aluminum POR 15. You can’t tell it’s been painted and it hasn’t discolored

I've been down this road many times, most coatings are expensive, and usually don't provide results that are desired.

I've tried plenty of DIY coatings too, again, expensive and not acceptable results.

Many times, once it does start looking 'off', you are either forced to strip it or paint over it.

What i've found to work best, for me at least, is Dupli-Color 1615 engine paint. It has the most natural shade and is readily available. And, you can touch it up while it's on the car.

https://www.summitracing.com/parts/shw-de1615

All the other paints don't have as good a shade as 1615, and I've tried a lot. The Eastwood 'As-Cast' is too dull IMO, all the others are too shiny. After one or two heat cycles, the 1615 ends up looking even closer to natural.

Engine paint sticks to pretty much everything, too.

It's best if you initially spray the part when it's new, I just do a quick wipe with acetone and do multiple light coats as directed.

If the part is stained/encrusted, bead blast, then etch it with Alumiprep or similar. Then spray as directed.

Pretty sure I've posted results/pics of this process here, maybe even several times.

Here's two pics, one from the mid-90s, and one from mid-20-teens, obviously before a couple heat cycles.

The last one is recent, when I did the 340cfm head/intake upgrade. Might have been one or two heat cycles on it.


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Here's an example of the VHT engine paint, was painted by the builder, but you can see it was too shiny. I did remove it and overcoat with 1615.



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My 455HO is completely powder coated. The head exhaust runners were ceracote first. Then powder over them. They didn't last that long. The powder flaked off them. The intake exh crossovers have been blocked off. Been 11 years now since I coated her

Eastwood used to make a stainless exhaust paint that was brush-on. On iron heads, I used to paint the exhaust ports, then use rattle can engine paint over it. That used to work real well, lasted a good time, and you would always touch up the engine paint along the way.

There's used to be a 2 part coating that was clear, bikers and hot rodders used to use it, was something Zoop Clear or close to that name. I tried it once, was a no-go for me, and did all the prep work cleaning the intake, etching, etc, and followed the directions to a T. One thing though, if I remember correctly, it only came in gloss, but not sure.

I powder coated a bunch on stuff in the engine bay once, did a core support, inner fenderwells, pulleys, etc. Over time it would haze. You could polish it and wax it, but again, it became a 'task', and then oversprayed it with rattle can engine paint.

I still say epoxy paint is a better option than powder coating, but that becomes somewhat a matter of opinion. I just won't pay to have stuff powder coated anymore, except maybe some interior stuff or specialty stuff, can get near as good, or even better results with epoxy. Especially if it's a driver.

I did just basic prep on my GTO engine compartment, core support, inner fenderwells, firewall, etc, and shot it with rattle can engine paint. If it needs a touch up in an area, it's easy to find the paint, and easy to apply. Think the black in engine compartment I use is a Ford semi-gloss or matte black, works for me.

I did powdercoat the GTO frame though, and after that experience, I kick myself for not doing epoxy.

Drivers, keep it simple seems to work best.



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Quite a few choices here, I appreciate all of the responses. thanx all!

I'll post what I finally decide.

George