# Gtechniq c5 alloy reaction on gloss black wheels.



## wish wash (Aug 25, 2011)

First off I will apologise for no pictures. 

Had my wheels powder coated gloss black, I chose to use gtechniq c5 as, 1, I love there products and id seen how easy brake dust came off and no need for wheel cleaners etc. 

When I came to wash the car a few weeks back I noticed that they are no longer gloss black but more like a matte purple. Some reaction has taken place and im not sure why. I've only ever washed them with water and no one has washed my car.

So why would it change colour. I did email rob at gtechniq but he never bothered to reply to my email. 

Does anyone have any suggestions?


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## Blackmondie (Mar 13, 2011)

can't help you, but I'm quite sure rob will reply. maybe he doesn't know the answer yet and they are figuring it out and doing some test. 

have you tried taking it off again?


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## Blueberry (Aug 10, 2007)

I would post this in the Gtechniq section (if you haven't done already). I''m sure Rob will reply to you there, when he sees it.


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## Snowglobe (Jan 12, 2008)

I can't imagine a wheel cleaner that could be strong enough to change the powder coating, from memory, powder coated wheels are baked, I would have thought that was pretty permanent.

Is it worth checking with the people that did the powder coating for you?

When I had some wheels powder coated they never budged, 5 years later they still looked like new.


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## wish wash (Aug 25, 2011)

That's my point, I haven't used anything on them apart from water. It happened a few weeks after I had them done, as winters on the way I want them sorted and protecting


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## Scrim-1- (Oct 8, 2008)

How long after being powder coated did you apply C5?


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## wish wash (Aug 25, 2011)

applied it a few hours after they were done. Powdercoats baked in an oven at 180c so I didn't see a problem, wouldn't of thought its like paint and that you should let it gas out for at least 30 days etc before protecting


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## gtechrob (Sep 11, 2006)

hi wish wash - firstly apologies if i didn't come back to you on email. we struggle with email volume on occasion.

c5 is a clear liquid and forms a clear film so it's not the coating per se but what I am thinking is that it could be down to excess product?

without seeing a pic it's hard to judge - email me personally - robearle at gtechniq dot com with pics and I can see what we can do :thumb:


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## minnnt (Mar 5, 2007)

Bet the purple looks better than the black anyway.


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## Benjic2 (Apr 21, 2010)

Have you been on a track or given the car/brakes a good beating recently? Same happened to my wheels and calipers after a track day. Stripped them back down by claying and polishing then re-sealed and they came up brand new again. Must be a reaction to the heat


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## isherdholi (Sep 18, 2007)

I would have thought the solvents in the newly powder coated wheels would need to fully cure before waxing/sealing, similar to fresh body paint work. (which takes about a month).

Maybe the solvents in the sealant have messed up the solvents in the powder coat?


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## Junior Bear (Sep 2, 2008)

A few hours is a bit quick IMO


Doesn't the lacquer need to breath for a few weeks??


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## renny (Aug 31, 2009)

What was the outcome with this, was it due to using it too quickly after powder coating or some other reason?


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## jamie_s (Jul 10, 2009)

Remember powder coating (as far as I can gather) is just plastic powder and the baking process melts it into liquid form and dries as the finished coating. It's not like paint where the solvents have to evaporate. Specifically 2k paint which involves a chemical reaction resulting in a very tough and very chemical resistant coating which isn't really affected by solvents once the reaction has finished. I'd imagine powder coating isn't as resistant to chemicals as proper 2k paint.


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## renny (Aug 31, 2009)

jamie_s said:


> Remember powder coating (as far as I can gather) is just plastic powder and the baking process melts it into liquid form and dries as the finished coating. It's not like paint where the solvents have to evaporate. Specifically 2k paint which involves a chemical reaction resulting in a very tough and very chemical resistant coating which isn't really affected by solvents once the reaction has finished. I'd imagine powder coating isn't as resistant to chemicals as proper 2k paint.


But surely the lacquer that is applied afterwards would be?


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## jamie_s (Jul 10, 2009)

renny said:


> But surely the lacquer that is applied afterwards would be?


I think the final clear coating is the powder coat finish. That's the idea with the powder coat being thick and soft so more resistant to chips whereas the 2k finish is much harder and has a higher gloss aswell as being more resistant to chemicals and scratching. Being harder means it's more likely to chip but isn't usually a problem if prepped correctly. I know more about 2k than powder coating so if I could be wrong.


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## Yellow Dave (Apr 5, 2011)

Most refurbed wheels that are powder coated, are then spray painted with the final colour then clear coat to get the finish, as a bare powder coat finish looks pretty pants


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## jamie_s (Jul 10, 2009)

Yellow Dave said:


> Most refurbed wheels that are powder coated, are then spray painted with the final colour then clear coat to get the finish, as a bare powder coat finish looks pretty pants


Ahh I see. I'm guessing those companies are a fair bit more expensive that the ones who charge around 30 per wheel! I've seen some pants finishes on p/c wheels so I imagine they aren't painted over. Doesn't make a lot of sense to powdercoat and paint though as the paint on top is still harder and more likely to chip? May as well strip the wheels and use a good primer.


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