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View Full Version : Can Bird Poop Etch Clear Coat?

07-30-2002, 11:20 AM
My 2001 Cosmo Blank 540i appears to be the victim of Bird Poop etching the clear coat. The bird poop was only on the car for 24 hours - but apparently that is too long. I took some 3M Fine Polishing Compound and tried to work the surface - it made it a little better, but you can still see it when looking at it from an angle.

I went to a body shop and they told me that Bird Poop can in fact etch paint and that you have to get it off within 8 hours - but that it depends on what the bird ate.

The told me to try wet-sanding with 3000 grit paper - no more than 5 to 10 strokes. I'm real nervous about trying this.

Anyone have experience with this?

07-30-2002, 11:54 AM
It sure can - that's the joy of having our wonderful feathered friends using our cars as toilets.

The 3M Fine Polishing Compound is pretty good stuff; I'm surprised it didn't take the full stain away, but if it didn't, that tells me that the finish is indeed etched.

The only way you'll be able to remove it completely is to remove the damaged clear. You can accomplish this with 3000grit (as bodyshop said) wetsanding. Or, you might want to try something like Meguiar's Body Shop Professional Diamond Cut cleaner first - it's more agressive than the 3M fine polish, so be careful with it.

Always try to use the least aggressive manner when dealing with stains and etching - I'd say try the Diamond cut first, then go with a quick wetsand, followed by polishes & waxing.

Good luck, and heads up! ;-)

07-30-2002, 12:28 PM
I am stunned that it can etch into the clear coat in 24 hours - even with the finish protected with P21S (which I had just done about 2 weeks ago). Maybe you ought to add a new test category to "TheWaxTest"......

Do you think that continue polishing with the 3M Fine-Cut Compound will eventually be able to polish the clearcoat so it is smooth like the rest of the car. I can feel the difference in the paint with my fingers - the clearcoat has been etched just enough to make it duller and not as smooth as the rest of the paint. You can't see it looking at it directly, but at any angle, it really stands out.

I also have the 3M Medium Cut - but am concerned about going through the clearcoat. The guy at the body shop was saying that the 3000 grit is the best way to get the surface flat and perfectly smooth - and implying that compounding it would not make the surface flat because the compound would follow the contours of the etched surface.

07-30-2002, 06:02 PM
We did notice that leaf acids etched through the clear on our panels that were treated with Zymol; we noted when etching took place, but for the most part, the waxes protected the panels pretty well.

I'm not sure why the bodyshop guy would say that about the compounds - agressive compounds have abrasives that are probably more coarse than a 3000 grit paper; the abrasives don't know a contour from another portion of the surface - that's how people using agressive products burn through their clear coats on corners, edges, etc...


07-30-2002, 09:41 PM
Yeah, I've given up on Zymol - It's too much work for what you get out of it.

I think he was implying that wet sanding could make the surface flatter with less material removed than with compounding. Not sure why he said it, but when I questioned him, he told me that he has been doing this for 28 years.....(yikes!).

I guess you don't agree and think I should continue with a fine cut compound like the 3M stuff.

07-30-2002, 10:04 PM
Sorry for the confusion. 3M should work well. If you're comfortable with using it, keep using it. As far as wetsanding removing less material, that's pretty unlikely, but 3000grit is really fine, so it could be a toss-up.

My motto is: "Go with the least abrasive product that will fix the problem." I stick to this all the time, because I'm a fan of keeping as much clear coat in tact. If the 3M will remove the rest of the stain, I'd go with that. If it doesn't, then I'd consider the Meguiar's or the 3000 grit paper route.

Best of luck! :-)

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