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Discussion Starter #1
Was looking to buy another muscle car today(Dodge Charger) and it has what appears to be yellowing under the paint. Is this a repairable condition or does it require stripping the car down to the bare metal. Dupont base coat was used they told me about 9 months ago. It's a white color. 2 coats Dupont clear. It almost appears to where the body was repaired and filler used are the only affected areas. The paint won't deter me from buying it but I'd like an idea of this condition. I don't want someone to sand & paint and this show back up.----:confused:
 

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I am pretty sure it's in the clearcoat. I have heard of a yellowing problem happening when people spray clear on when it is too cold. Anybody else know why this would be happening?
 

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I have saw a lot of cars come in with this problem. What I have learned over the years is that the body guy got into a hurry and put to much hardener in the mud. There is nothing wrong with it but it will bleed through the color. If the car is in good shape out side this you can wet sand it down with 600 paper. You really need to use a good sealer and shoot color.I would not worry to much.Some times cheep clear will yellow after some time but not just in spots. Good luck with your new find.
 

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Your statement that it looks like its happening in area's with body filler may be correct.
This was a major problem when basecoat/clearcoat first came out
light colors such as white, pastels, some silvers after the paint dries would Bleed or stain the paint. This sometimes would take
30 minutes to show up and sometimes 2-3 months later.

This problem was blamed on putting to much hardener (peroxide) in the filler and yes that could help cause it but was not the real cause. The bodyfiller companies made major resin changes back then to help stop the problem and the clear manufacturers also had to do some major revisions.

It rare to see this happen today but it sure can! When you see the problem pop up today, its not the filler usually doing it, its a two part glazing putty.
To cause this problem there MUST be abuse to get the yellowing results and heres how.

Rushing the product.- Sanding the filler right away and than applying primer. You see this a lot with dealerships doing warranty type work (small dings)

Full repaints- The fillers are not going to bleed because of how large the job is as they have enough time to dry but last minute before painting the painter hits all the bad spots with a glaze and sands and right away applies sealer and next day little yellow spots.

To repair-
*Sand and a coat of epoxy is about a 95% (not 100%!) corrective repair. The stain can bleed back through the epoxy.
*2K primer is about a 30% repair chance in your favor.
*2K sealer is same as 2K primer.
* Waterborne primer is a 100% sure cure.
Ideal way to repair is sand clear off in the problem spot and set it sun for a few days or use a Short wave lamp to draw rest of stain out than epoxy and repaint..

Bottom line what causes staining is applying the primer to soon.
 

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Discussion Starter #5
I really appreciate all of the imput on the yellowing condition.
Thanks for your help and replies---------------:thumbup:
 
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