Clear Repair Clarification

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PostPosted: Sun Apr 18, 2021 5:52 pm
I unknowingly buried some dirt on a wide, white rally stripe with the first coat of clear. I finished the job by continuing to clear the entire car with three coats total.

I know from everyone's past advice that once the area has been scuffed, (or maybe some of the clear sanded off to prevent excessive buildup?), the area should be blended with base and then the entire panel should be cleared. My thought was to just reclear the stripe.

I am going assume it's OK if I clear with just one, maybe two coats. However, when I do my planned wetsanding and buffing, if I break through the new clear into the original clear will I see the transition? I'm wondering if I should lay down three more coats so I am only sanding the new clear layers. If that's the case I feel like I should remove most of the clear to keep the buildup down.

What do you think?



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PostPosted: Sun Apr 18, 2021 7:31 pm
so i would be interested in how you did the stripes? another words do you have a tape line at the stripe now? you do know that you'll have to spot and blend with the white base. that's a problem with white you have to be squeaky clean. answer the questions above and we'll see what to do with the clear.
Jay D.
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PostPosted: Sun Apr 18, 2021 7:45 pm
Sorry, I don't understand what you mean by "Tape line at the stripe".

See if this helps: I based the car then applied two coats of interclear. I then masked the stripe and applied two coats of white base, then three coats of clear over the entire hood.

I understand I'll be blending, but I assume I will be blending the white on top of the original clear? IOW, the layers in order from the panel: Original base, original intercoat, original white base, original clear, new blended white, new clear. Is that how that works?



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PostPosted: Mon Apr 19, 2021 11:29 am
so it looks like you had a smooth finish. if you just blend the white color then clear just the white your going to have a tape edge that's going to be difficult, to remove. i would repair the white and clear the complete panel. might be easier that way, after you ether sand or buff through the edge of the clear coat on just the white.
Jay D.
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PostPosted: Mon Apr 19, 2021 5:53 pm
Yeah, I think that's easier than trying mask and clear just the stripe.

But what about if I sand through the new clear into the old clear? Will I see the dividing point between the two layers? I plan on removing as much as I dare of the old clear and lay on another two to three coats for wet sanding. I don't like the idea of that much paint if I don't remove some of the old clear.



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PostPosted: Mon Apr 19, 2021 6:49 pm
MAYBE someone else can chime in. because i don't know what to tell you about cutting through the new into the old. in all my years i don't think i have run across that problem. my gut feeling is you'll see a line just like trying to blend out clear on a spot repair and trying to buff it smooth. it just doesn't work good, unless you use some other products such as adhesion promoters, but that's another story. i would just sand the old finish smooth then shoot 2 good wet coats and call it a day. you'll be amazed how smooth the clear goes on over the old clear. a quick session with a d/a and some 1500 or 2000 then buff. no need to worry about cutting through 2 wet coats, unless you leave the d/a running in one spot for 3-4 min.
Jay D.
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PostPosted: Tue Apr 20, 2021 6:01 am
On a job like this I probably would have measured paint thickness after each major step so I knew exactly how much was on there. Paint thickness gauges are not that expensive these days and a little knowledge can empower you when something like this happens.

The problem you have now is that you have absolutely no idea of how much clear you have on there so "taking off as much as I dare" is a proposition that is fraught with danger.

Your options are:
1. Guess that you put on maybe 60μm and take off half of that which is, approximately 1/1000 of an inch. How will you know how much you've taken off?
2. Take it all of and start again. This would be the technically correct way and ensure that total DFT does not exceed the maximum of about 300μm.
3. Scuff it up really well and just put another layer on top. Take this opportunity to reduce peel if that's necessary. If the dirt spot isn't too close to the edge of the stripe then mask at the edge but just dust some white base over the spot, staying well away from the edges so there is no buildup there. A small gun would make it much easier - I'd use a 0.8mm with the fan set in to maybe 30mm and flick out maybe 30-40mm from the centre. Practice this beforehand so you don't end up with a big wet spot. Do your testing on brown paper or cardboard so you can see how far your overspray goes. If it's the same paint you used before you'll never see it if blended, especially being white. Once flashed off just put two more coats of clear over the whole bonnet, as though flow coating.
Chris



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PostPosted: Tue Apr 20, 2021 10:44 am
:goodpost: Chris do you have an opinion on posibly cutting through the newly applied clear into the old. will there be a detectible line between the two? THANKS
Jay D.
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PostPosted: Tue Apr 20, 2021 5:53 pm
Can't say it's happened to me much, Jay.

I know that I've cut flow coated clear pretty deep a few times and never seen an edge but I think it would depend on how old the underlying clear is and how well prepared the surface is. A substrate that isn't well sanded/scuffed may show some lifting at an exposed edge where the mechanical adhesion isn't good enough. I have seen that happen and the edge was visible, but after re-clearing it disappeared.
Chris



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PostPosted: Wed Apr 21, 2021 11:20 am
THANKS, :bighug:
Jay D.
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