uncorrectible spot etched paint from tree droppings

[m3d]

Background: The car is a 2005 ford escape (my "everyday beater" when I'm not driving my M3), but I still like to keep it in top condition.
The car had a coat or two of Klasse Sealant Glaze on it within the past 2 months (put on by me)
Paint was in perfect condition no defects

I park under this tree, I have never had any problems with
It's a cottonwood and it started dropping these green seed pods
Normally the clear liquid marks wash off pretty easily with soap and leaves no damage. (not a problem)

Little did I realize that this liquid if given too many days will turn to a dark brown and harden almost like an enamel!
So I clay barred the entire car for like 3 hours to get all these spots off one by one.very annoying.
All the car paint that is "over sheet metal" has no damage what so ever.

However
The clear coat on the rear bumper, (which may be a softer clearcoat?)
has dime sized marks that have tiny micro scratches in them which cannot be removed.
I have used the most aggressive yellow pad, even used 3m rubbing compund (the one that removes 1200 sanding scratches)
They have minimized the damage, but these spots still look hazy from an angle (not from the compound)

The damage almost looks like when egg protein drys on the clearcoat and cracks it, but the cracks are so much more finer.

So I guess my question is this:
Has anyone experienced this type of problem with cottonwood trees?
Why exactly did it damage only the rear bumper paint (was not a repaint), yet leave the rest of the car ok?
Do bird droppings and certain saps burn through Klasse SG if left more than a few days? Is it just inevitable?

I'm probably crazy for obsessing over these things, because the car definately has an area or too that is worse that these etch marks.
But I'm obsessed with keeping whatever I can in best shape.

[Mike Phillips]

First, since this is your first post...

Welcome to Autogeek Online!

However
The clear coat on the rear bumper, (which may be a softer clearcoat?)
has dime sized marks that have tiny micro scratches in them which cannot be removed.

I have used the most aggressive yellow pad, even used 3m rubbing compound (the one that removes 1200 sanding scratches)
They have minimized the damage, but these spots still look hazy from an angle (not from the compound)

The damage almost looks like when egg protein drys on the clearcoat and cracks it, but the cracks are so much more finer.

A picture would help but from an article I wrote on Bird Dropping Etchings, here's a picture that sounds like what you're describing?


Two Types of Bird Dropping Etchings

Type II Bird Dropping - Fractured/Wrinkled Etching
Type II Wrinkled Etchings are usually too deep to fix safely. The problem is the paint fractures, (splits apart in tiny lines,), or wrinkles as the paint swells and bunches together. In both instances, the resulting defect is throughout the clear layer of paint and not topical. Thus trying to remove it will require removing so much clear paint that you will likely expose the basecoat, or colored layer of paint which has a dull appearance. For this reason it's not safe to try to remove a Type II Bird Dropping Wrinkled or Fractured Etching.

Photo courtesy of AutogeekOnline.com

Couple of comments...

The tiny cracks in the paint, like you see above, travel throughout the layer of paint, they are not simply topical defects.

As such, abrading the paint will just uncover more and more of the cracks. By the time you get all the way to the end of the cracks you will likely go through the clear coat or leave it so thin it will fail over time due to exposure.

As for why only the bumpers were affected and not the car body panels, my guess is the type of paint is different. It's the same color but paint used on urethane rubber/plastic components uses a flex additive so the paint won't crack when the component flexes.

Also, with some cars, different components are farmed out to outside companies to manufacture and paint, these components are then shipped to the assembly plant and attached to the vehicle. Point being that while the car may be all one color, the paint systems can be different from panel to panel.

Sounds like if you didn't get anywhere with the compound that you might have to live with the defects and cut down the tree...