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Not Sure I Even Want To Powder Coat?

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Old 01-06-2015, 11:39 PM   #16
Crumpler
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I have to express my gratitude again you guys, really.
That's a ton of good advice.
Man, my vision had a lot more clarity when I was ignorant of the Magnesium component. Lol.

I guess my gut feel is that if it can be done, I would like to try it. As a few have mentioned -- it would look pretty damn sharp if it works out.
I have not had time to do much more then token research so far.

Effectively, a tedious sanding or a media blast, then polishing followed by a clear coat agent.

Matt I had thought about black urethane as a back up, do you think it would hold up at heat?

I have come across some concerns over clear coat paint in old threads, even the high temp products, yellowing with time and heat.
I came across a scary thread on Pelican, as per clear powder coatings that have not turned out well, due to different factors and even the substrates used on media blasts and the like.
So I clearly have plenty of work ahead of me, in research as well as elbow grease.
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Old 01-06-2015, 11:42 PM   #17
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My S3 intake was completely removed late in 2008, powder coated, and re-installed early in 2009, along with new injectors, seals, gaskets, you name it.

The powder coating was done by 928 Motorsports. The color match is indistinguishable from the factory color (Zermatt Silver if memory serves) and today it looks as good as new. Not a flake, void, bubble or even the slightest bit of discoloration yet.

This was (very) expensive but I got what I paid for and more.
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Old 01-07-2015, 10:14 AM   #18
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Quote:
Magnesium alloy is a chemically very reactive metal.

From the microsecond it's produced it reacts with atmospheric oxygen to produce magnesium oxide - a white powder - that will prevent anything from adhereing to to the surface of the casting.

For this reason the surface must be chemically passivated - ie a chemical must be applied to the surface to react with and specifically bind with the Magnesuim atoms to prevent them from reacting with oxygen.

This is the dark gray layer seen under the OEM paint as it flakes off, and is the surface passivation layer laid down by the foundry supplying the castings to Porsche.

Should you want to remove this to the bare and very shiny metal it will be a sight to behold, but you must have a means of immediately clear coating the mag alloy as soonn as that coating is removed.

Best of luck, but the end result should be well worth the effort.
+1 Exactly right.

Getting paint (powder-coated or otherwise) to stick to magnesium is a real challenge.

I have several pictures of finished manifolds we have done here:

http://www.928motorsports.com/servic...dercoating.php

PS: do not compare polished 16v intake runners (aluminum alloy) to the idea of polishing the 32v manifold (magnesium alloy). Not same.
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Old 01-07-2015, 10:21 AM   #19
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Once u powder cost one part yourself you become addicted
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Old 01-07-2015, 11:23 AM   #20
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I started powdercoating at home quite a few years ago and it turned into this.. www.legendgarage.com
Yep, it is addicting and not for the faint of heart. ESPECIALLY 30 year old oily Magnesium castings.
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Old 01-07-2015, 02:57 PM   #21
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Just send the parts to Ben. Choose the color you want. Then pull the cam covers and have them finished to match. Or just send ALL that stuff in one batch. Get injectors/hoses/gaskets/seals/plugs/cam chains ordered at the same time. Do it like you mean it.

My car ran fine before the intake and cam cover refresh/refinishing with new collateral (WYAIT) parts. Ran even better after all the new stuff was installed. With the powder coating, it runs better than before even just sitting there cold with the hood open. The improvement just in appearance is that good.
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Old 01-07-2015, 07:13 PM   #22
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As usual the affirmation bias is strong - people who PC'ed say PC is best. I'll go against the flow

I got my 87 intake/cam covers PC'ed a couple of years ago. Its held up fine and still looks the same as it did when the part came back to me (the car is my DD), and I've been happy with it.

Next time however, I'm going with paint, having seen a local S4 who went with a high-build high-temp epoxy paint process on the advice of the local Porsche dealership's paint and body shop. The depth and distribution of the metallic flakes just make it pop compared to PC.

I'll try to get pics which do it justice next time I see his car.
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Old 01-07-2015, 09:00 PM   #23
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Quote:
Originally Posted by Hilton View Post
As usual the affirmation bias is strong - people who PC'ed say PC is best. I'll go against the flow

I got my 87 intake/cam covers PC'ed a couple of years ago. Its held up fine and still looks the same as it did when the part came back to me (the car is my DD), and I've been happy with it.

Next time however, I'm going with paint, having seen a local S4 who went with a high-build high-temp epoxy paint process on the advice of the local Porsche dealership's paint and body shop. The depth and distribution of the metallic flakes just make it pop compared to PC.

I'll try to get pics which do it justice next time I see his car.
That's the way I'm going on the GTS. The guy who did my wheels here in Tasmania is a perfectionist, does lots of race and high end work, and he's doing all my top end parts. I told him I wanted every area perfect, and that's what I'll get. Here's a couple of pics of one of the wheels he did, and he'll get the same perfect finish on the engine parts.
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Old 01-07-2015, 09:31 PM   #24
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A real epoxy finish does open up a lot more possibilities around metallics and such. "Regular" paint has those options minus the durability that epoxy and PC offer. Installation of the intake and cam covers does involve sme risk of casual damage, particularly as other parts are fitted as part of the process.

My PC'd intake looks great but it isn't perfect. That said, my original as-purchased intake and cam-cover finish wasn't perfect when I got it at 22k miles. The PC finish is superior to what was delivered on my car. I did seriously consider painting options, particularly since I wanted the color to match the original perfectly. Getting a perfect Zermatt Silver is simple, just buy the right Zermatt Silver and spend time on the correct prep for that paint. For the PC, Rob & Greg worked with the PC shop to get as close as possible to the original color. There were enough variations in original color tat I could argue "originality" across a range of silvers. Still, the match was made with what was originally on my pieces, and I'm happy.
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Old 01-07-2015, 10:00 PM   #25
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Quote:
Originally Posted by Chalkboss View Post
Here is what an S4 intake looks like oxidized. I did sand a few bits and you can see the difference in these areas.
Chalkboss, that's not oxidation; it's the result of 'surface passivation' treatment ie a treatment to bind the Mg atoms to another molecule so the Mg can't react with oxygen in the air.

When Mg reacts with 'air' it produces MgO, a white powder.

It's a case of the original factory coating eventually coming unstuck.


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Old 01-07-2015, 11:34 PM   #26
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So I've been chasing down some info when I can at work.
I reached out directly to the Shark-Hide manufacturer today by phone.
We talked about what I had on my hands and what I was trying to do, pretty good guy I gotta say.

So he felt his product has been used on magnesium/aluminum alloys before and had very good results. "No worries"
He is of the mind that nothing will stick to any polished metal alloy anyway, which is a concept that I can buy into. I would have to media blast, sand, passivate, or etch to get a clear coat to adhere -- which kind of defeats the purpose of what I am trying to pull off.

The concept is I will get down to the alloy, wet sand to a 2000, one product to polish, cleaning process, then second product which is the actual protectant.

I'm going to give it a shot, what the hell.
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Old 01-07-2015, 11:51 PM   #27
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That's going to take a long time. Mechanically/Abrasively polished surface is still rough enough for anything to stick to. After all, that's what polishing is, creating scratches. However the overall goal is to make them so small they are invisible.
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Old 01-09-2015, 12:05 AM   #28
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Ben Powdercoated mine, one of the best upgrades I've done!!
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Old 01-09-2015, 01:32 AM   #29
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The battle with any blast-abrasive-polish-seal is the time between the last full abrasive cleaning and the coating. In the aircraft industry, the allowable exposure time is less than an hour. The net effect is depndent on ambient temp and humidity, but shorter is better. I looked at those limitations when I decided on the PC process, since the pieces are rolled directly from last chem cleaning and passivating right to the PC line without being touched. That limits the repairs that can be done, BTW, and the cast intakes and cam covers could really use some detailing.
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Old 01-09-2015, 10:02 PM   #30
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The results are promising so far, but you don't want to even know how much time this takes.



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