Failing clear coat respray help

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PostPosted: Fri Sep 10, 2021 11:39 am
So I am looking for some seasoned advice on an issue I am having with my factory GM paint. Basically, any horizontal surface has had catastrophic clear coat failure. Hood, roof, trunk deck. It started with kind of looking like someone took a scratch pad to it... then turned hazy. I don't know the technical term for it, it doesn't look like typical "crazing" because the cracks/scratches are much more uniform and less random. Dealership told me GM messed up the hardener ratio at the factory and it's a known issue. They were kind enough to offer to charge me for a new paint job at full price because my warranty expired 3 months before it happened (coincidence?)

So here I am... I know the clear needs to be removed completely before I can do anything. Should I just sand off the clear coat to the factory base and start from there? Should I use sealer or primer? or both lol.... Someone once told me if I'm careful enough with the sanding I could probably just buff/polish the existing paint and respray clear over it, I'm no pro but that sounds a bit like asking for another failure in the clear. Ya'll got any words of wisdom for me here?

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PostPosted: Fri Sep 10, 2021 4:26 pm
Pictures help but I'll assume it looks something like this:
IMG_0126.JPG


The clear coat protects the base/color coat and once it fails the only option is to strip it and repaint.
1968 Coronet R/T


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PostPosted: Fri Sep 10, 2021 4:53 pm
Well no it looks more like hazy clearcoat with micro scratches. It's not peeling up... yet. I would post a pic but it's been raining all day.



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PostPosted: Fri Sep 10, 2021 9:07 pm
strip it down to bare metal, when its said and done it will be easier, better and most likely cheaper. forget about saving the base coat, or doing any buffing. I've done a ton of these and it didn't take me long to figure the best and quickest way to do this.
Jay D.
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PostPosted: Fri Sep 10, 2021 10:25 pm
Yeah, seen at least a half dozen of this problem... don't save ANY of that paint package. Nothing there is worth building a new paint job on.....down to metal you'll go....
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PostPosted: Wed Sep 15, 2021 9:16 am
To metal I go I guess then. This is what I have in mind... correct me if I'm wrong.

DA sander first stage 180, second with 400 down to metal

Epoxy Sealer x2

Primer x2

Wet sand with 400

Base x3

Clear x3

Cut'n buff

I shouldn't have any issues with adhesion starting at the edges of the panels should I? I really don't want to have to do both sides lol Is 400 grit enough for the primer prep? I don't want to go too smooth but I also dont want to see scratches in the clear... I don't need to seal the primer again do I? I have heard so much back and forth about this topic. Also living in South Central Florida..... Are 3 coats of clear enough? I'm on the fence.

I think it's worth mentioning the paint color is "Dark Sapphire Blue Metallic"
Last edited by 40ozFatality on Wed Sep 15, 2021 10:42 am, edited 2 times in total.



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PostPosted: Wed Sep 15, 2021 10:24 am
Also a follow up question... I have a GTI Pro Lite 1.3mm... Never tried to put primer through it. Would I be able to do all stages with a 1.3 or should I get a 1.7 for the primer/sealer?
Last edited by 40ozFatality on Wed Sep 15, 2021 10:57 am, edited 1 time in total.

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PostPosted: Wed Sep 15, 2021 10:56 am
DA with 80 grit is good prep for epoxy primer. It will also get rid of that old paint much quicker.

Build primer will need a larger tip. 1.8 - 2.0 are most common.

Guide coat on build primer before wet sanding. Most do this in two steps, say 320 and then more guide coat and 600 to finish for metallic paints.
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PostPosted: Wed Sep 15, 2021 10:59 am
there are several ways to remove the old paint. i use an 8" air sander with a firm foam pad and m36 grit paper i can strip 90% of a car in about 2 hours maybe 3hr. on a full sized pick up. you'll need a BIG compressor to do this. you can also put the same pad and paper on an elect. sander it MUST BE A SANDER not a grinder a grinder is to fast to many rpm's. you can use paint stripper, there are some tricks to make this easy, but good paint stripper is hard to get now days. you can use a razor blade scraper, use it by its self or better yet with a heat gun. your D/A will work BUT not with 220. it will take you a life time with 220. if your D/A will lock so it doesn't oscillate orbit do that and put 36 grit paper on it to cut most of the paint off then finish with 80 grit. for paint on the bare metal i like to use epoxy, 2 good wet coats then i block the epoxy with 80 grit this will show all your defects. be sure to use a good wax and grease remover on the bare metal, you want it squeaky clean. repair defects and spot prime with a hi build primer block with 180 until perfect, you may need to prime a second time or more what ever it takes to get it perfect. i like to lightly go over the complete job with a block and 180 just to remove some of the 80 grit profile from the epoxy. now your ready to shoot the complete job with a couple coats of hi build guide coat it and block. i will generally block this primer coat with 180 or 220, i want to make sure everything is cut flat. i'll then shoot one good wet coat of primer on then guide coat and sand with with 600 - 800 depending on how smooth the primer is laid down. now your ready for color.
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PostPosted: Wed Sep 15, 2021 11:03 am
:goodpost: :goodpost: :goodpost:
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