Removing minor dieback

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tguil

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The hood on my white Ram was recenty repaired and repainted. The repair involved a small dent in a corner of the hood. The repair was made and base coat was blended into the factory paint....a very good job on this part of the repair. The whole hood was then cleared using a "coat and a half process" which gave a sufficient mil thickness. However, there was a bit of "dieback" in the clearcoat. The body shop lightly sanded the whole hood with Trizact 3000 and then buffed the hood with a rather mild polish. I think the approach maybe could have been a bit more aggressive because there still is a bit of the "dieback" present. It is visible only under fluorescent lighting.

I am quite sure there is enough clear for a little more buffing. Right now I am planning to use a Porter Cable PC and foam pads to smooth things out a bit. (I don't want to use my Makita Rotary unless I really have to.) I have only Meguiar's products available in my arsenal....Meguiar's maroon cutting pads, Meguiar's polishing pads, Meguiar's Ultimate Compound and Ultimate Polish. Basically pretty safe stuff and I am in no hurry to get this done...the reason for using the PC rather that the Rotary.

I don't want to do any more sanding because it might make the surface too smooth. My Ram is blessed with considerable factory orange peel.

Any suggestions on using these products.

Oh, I could have pushed for more work to be done by the shop, but I chose not to. I tend to be more cautious than most body techs. If for some reason the paint "goes south" in a year or two, I'll plead ignorance and have it redone.

Again... the dieback is in the clearcoat only.
 
"Die Back is the loss of gloss after application (if using glossy topcoat). It is caused from improper evaporation of solvent, poor initial cure, or paint not flattened sufficiently."
 
Setec Astronomy said:
"Die Back is the loss of gloss after application (if using glossy topcoat). It is caused from improper evaporation of solvent, poor initial cure, or paint not flattened sufficiently."
Click to expand...
Yep, that's it. The shop owner thinks the temperature in the booth might have been off just bit...sort of funky weather when the painting was done. This is a a "state of the art shop" with well trained techs. The condition is most certainly not bad enough to justify more paintwork. I can only see the "dieback" through my trifocals in just the right light. It actually looks a bit like "micro orange peel" or perhaps an egg shell. (Yeah, I'm an "old guy"...been messin' with detailing for over fifty years.)
 
Sometime in the next day or two I plan to "get at it". I know that "least aggressive" is best, but the clearcoat has been on the truck for three months. I'm thinking about using Meguiar's maroon cutting pad with Meguiar's Ultimate Compound and then follow up with Meguiar's Ultimate Polish on a Meguiar's polishing pad. (I've used the maroon pad with PC before and didn't have any problems.) From what I have read, the Ultimate Compound and Polish are more user friendly than Meguiar's 105 and 205 and with patience they can still "get-r-done".

Any suggestions? If there might be a better product combination using a PC rather than a Rotary or more sanding, I most surely will consider it.

In direct sunlight the "dieback" is not visible.
 
Last edited:
tguil said:
The hood on my white Ram was recenty repaired and repainted. The repair involved a small dent in a corner of the hood. The repair was made and base coat was blended into the factory paint....a very good job on this part of the repair. The whole hood was then cleared using a "coat and a half process" which gave a sufficient mil thickness. However, there was a bit of "dieback" in the clearcoat. The body shop lightly sanded the whole hood with Trizact 3000 and then buffed the hood with a rather mild polish. I think the approach maybe could have been a bit more aggressive because there still is a bit of the "dieback" present. It is visible only under fluorescent lighting.

I am quite sure there is enough clear for a little more buffing. Right now I am planning to use a Porter Cable PC and foam pads to smooth things out a bit. (I don't want to use my Makita Rotary unless I really have to.) I have only Meguiar's products available in my arsenal....Meguiar's maroon cutting pads, Meguiar's polishing pads, Meguiar's Ultimate Compound and Ultimate Polish. Basically pretty safe stuff and I am in no hurry to get this done...the reason for using the PC rather that the Rotary.

I don't want to do any more sanding because it might make the surface too smooth. My Ram is blessed with considerable factory orange peel.

Any suggestions on using these products.

Oh, I could have pushed for more work to be done by the shop, but I chose not to. I tend to be more cautious than most body techs. If for some reason the paint "goes south" in a year or two, I'll plead ignorance and have it redone.

Again... the dieback is in the clearcoat only.
Click to expand...


tguil said:
Yep, that's it. The shop owner thinks the temperature in the booth might have been off just bit...sort of funky weather when the painting was done. This is a a "state of the art shop" with well trained techs. The condition is most certainly not bad enough to justify more paintwork. I can only see the "dieback" through my trifocals in just the right light. It actually looks a bit like "micro orange peel" or perhaps an egg shell. (Yeah, I'm an "old guy"...been messin' with detailing for over fifty years.)
Click to expand...

Old guy to old guy.....:props: :laughing:

That's the first time I've heard the term used as well.

Is it possible to post a closeup photo of the defect?

I've got an idea of what you describing and it sounds like a little careful wet-sanding with 3000 on a rubber block should knock off the high spots for polishing. OR just use some compound on the affected area and try to match the rest of the hood..

Thy to avoid sharp edges as the paint is at its thinnest here...
 
The condition is so minor that a camera will not pick it up. Not only am I old, I'm a bit "obsessive" too. :D
 
Bobby, from what I read this is a solvent trapping phenomenon, so it may not be a "top-down" defect that can be sanded away, if it is further down in the clear...
 
According the the body shop owner and all of the paint troubleshooting websites, the "fix" is pretty much the same as orange peel...sand and/or compound and polish. If severe, sand and repaint. In my case the dieback is far for severe.
 
Setec Astronomy said:
Bobby, from what I read this is a solvent trapping phenomenon, so it may not be a "top-down" defect that can be sanded away, if it is further down in the clear...
Click to expand...

The way I visualized it was the slightly dull area was on the surface...

OH, I see, now I understand it better...Thank you! :props:
 
I've also heard the term dieback called shrinkage or shrink back.

I've had success simply re-sanding, compounding and polishing. Here's the deal, if it's topical, you can fix it. If it's under the clear top coat you can't.


Hate to sound like a broken recored but here goes...


When I want to troubleshoot a paint defect I'll place a tape-line down and buff on just one side of it. Then inspect.

You're either going to see you're making a positive difference, a negative difference or no difference at all.

If it's positive, then remove the tape and continue fixing the affected area.

If it's negative, post back here what you're seeing, we might we able to tweak your technique or process.

If there's no affect at all then it's likely the problem is under the clear.


:)
 
Find a friend with a really nice camera. It can pick up stuff you can't see with the naked eye. I'd love to see what you're talking about.
 
From this thread,

Time-Lapse Video: Wetsand, Cut and Buff 1964 Malibu


Here's picture 5 from above...

64_Malibu_Show_Car_Makeover_005.jpg


And here's two full size sections cropped out of it showing the sanding prep marks in the paint after the paint dried and shrunk back a little. All of these defects sanded and buffed out.

64_Malibu_Show_Car_Makeover_005a.jpg


64_Malibu_Show_Car_Makeover_005c.jpg



:)
 
Thanks, Mike.

I'll try to get at it soon. It's not even close to being as bad as the pics you posted

Tom :cool:
 
One more thing. With Meguiar's Ultimate compound should I go ahead and use my Meguiar's maroon cutting pad or wait and order an Optimum or Meguiar's microfiber cutting pad/disc? Might as well try for what might be most effective. What the heck, this isn't "rocket science", is it? :D

Tom :cool:
 
tguil said:
One more thing. With Meguiar's Ultimate compound should I go ahead and use my Meguiar's maroon cutting pad or wait and order an Optimum or Meguiar's microfiber cutting pad/disc? Might as well try for what might be most effective. What the heck, this isn't "rocket science", is it? :D
Click to expand...

Do you have some sort of orange pad? If not I would start with a polishing pad rather than that maroon pad.
 
Setec Astronomy said:
Do you have some sort of orange pad? If not I would start with a polishing pad rather than that maroon pad.
Click to expand...

Thanks for the suggestion. It may take a week to find that orange pad. I haven't used it for a while....no reason to.
 
Well, you know Mike always discouraged the use of that maroon pad back when he worked for Meguiar's...or do you have one of the new 2.0 pads?
 
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