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The mkiv Supra Owners Club

Clear coat over cast aluminium


KrisM

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Hi

Has anyone sprayed 2k clear aerosol or similar over the cast aluminium turbo intake pipes?  I just had mine vapor blasted and have come up looking great so rather than have them powdercoat want to clear protect them before they oxidise again.

Recommended brand welcome. 

Cheers

 

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I'd keep it maintained with a weekly polish.

If clear coating peels or cracks you'll have to remove it and repolish.

From a maintenance viewpoint I think polishing it probably better.

You can get clear anodising though. Maybe worth a look.

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My rule of thumb for painting is. If it can be dried by air it can be penetrated by air and water. Not good enough to fight the elements. 2k epoxy primers and 2k clearcoats do the job well until a stone chips them. Powdercoat id use to dress up parts inside the enginebay.

Edited by evinX (see edit history)
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From experience most clear or light colour paints in engine bay will yellow over time.  Powder coat isn't great in teh bay either unless its away from the engine/turbos.

You can get ceramic powder coats that'll cope better with heat but still not sure how long they'll last before the silvers go yellow.

i don't think you'll find a decent clear that doesn't but best bet would be some of the VHT branded paints.  I've used a silver one on my turbo heat shield and it still seems to be silver-ish. 

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26 minutes ago, Iky said:

From experience most clear or light colour paints in engine bay will yellow over time.  Powder coat isn't great in teh bay either unless its away from the engine/turbos.

You can get ceramic powder coats that'll cope better with heat but still not sure how long they'll last before the silvers go yellow.

i don't think you'll find a decent clear that doesn't but best bet would be some of the VHT branded paints.  I've used a silver one on my turbo heat shield and it still seems to be silver-ish. 

Powdercoating is great for the engine parts minus exhaust manifold areas. Great for heat exhange to.

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19 hours ago, evinX said:

Powdercoating is great for the engine parts minus exhaust manifold areas. Great for heat exhange to.

Standard powdercoat wont last long. Especially on cam covers/turbo alloy pipes. Probably look good for a few months to a year before it softens/blisters/cracks/discolours. If you can find a company that does ceramic/high temp type powders, theres one in coventry that I know of. Powder Lab I think it's called. That'll last much longer. 

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19 minutes ago, Iky said:

Standard powdercoat wont last long. Especially on cam covers/turbo alloy pipes. Probably look good for a few months to a year before it softens/blisters/cracks/discolours. If you can find a company that does ceramic/high temp type powders, theres one in coventry that I know of. Powder Lab I think it's called. That'll last much longer. 

Ive had powdercoated valve covers for around 3 years with no issues and have friends with other powdercoated engine parts longer than i have and still look great. 

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2 hours ago, evinX said:

Ive had powdercoated valve covers for around 3 years with no issues and have friends with other powdercoated engine parts longer than i have and still look great. 

We'll have to agree to disagree on that Kev, all the ones I've seen have shown signs of the finish degrading in roughly a year, including my own. If you look closely it'll have lost its sheen and become brittle and blister. Might look fine from a distance. 

Problem with alloy it that when it gets warm it 'gasses' out and starts blistering. That's why you need to preheat it before powder coating otherwise it comes out looking crap.  

Our engines run hot and constant heat cycling degrades it. 

I'd advise anyone that wants that super fresh painted look to last for a good few years, not to powdercoat cam covers and turbo pipes but find some other alternative coating that can handle high temps. It's fine for other odd brackets etc. 

I'm not too sure about NA cam covers as they're a magnesium alloy, I've not had any experience of powdercoating that. 

Just my opinion and advice of course. 🙂

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I'd have to disagree with that. Ive had my valve covers, inlet manifold and some other bits in the bay powdercoated for a few years now. Much better than any paint I've used, holds up well against the heat and is much more durable against scratches and such. These days, 2k paint or powdercoat/anodize is the way to go, everything else is a bit of a waste of time. 

From what I've seen nothing out there will give you a super fresh painted look after a few years unless the car is barely driven. It all turns to shit eventually. 

For OP, I've tried a few clear coats and such on fresh blasted parts before and its ok for intake side parts, but anything close to the exhaust turns a nice yellow/brown, so bit of a waste of time there. The best results I've had is to leave the parts bare after being vapor blasted, then use ACF-50 to keep it from corroding. Only problem is that if you drive the car enough you will have to apply new layers of ACF-50 on a somewhat regular basis to keep it protected, so bit of a ballache.  

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  • 2 weeks later...

Many thanks for the replies guys.  Must apologise i never had an email alert to say anyone had responded so havent been on 😬

After considering the options i think a regular wipe with brake cleaner will do so I can stick with the raw aluminium look. (Will look into the acf50 though) If they become too much work then silver or black powdercoat maybe.

Next job pull the intake manifold and get it done. Cheers

 

Edited by KrisM (see edit history)
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