White marks after wet sanding with 2000 grit (I think I burned my paint)

H

Honda Enthusiast

New member
Joined
Mar 1, 2017
Messages
8
Reaction score
0
Dear all,

I am new to this wonderful forum, and also new to car detailing, I detailed a couple of cars with hard paint but first time to work on my wife's Honda Accord. I was sanding a bird drooping on the hood, with 2000 grid with plans to do one pass with 3000 then compound then polish.

I always use 3M sanding papers, however this time I used a product called from auto zone (Finish 1st mini block as seen in the picture, I used the 2000 grid verison), what I liked about it, the block was very small to tackle tiny areas instead of sanding larger areas. I sanded for only 2 minutes only, then found this white spot on the paint. THE SANDPAPER WAS COMPLETELY TORN (SEE THE PICTURE). I didn't use a paint thickness gauge. it was the factory original paint, and I wasn't going to go deeper. I believe I made a mistake by not using a paint thickness gauge and purchasing unknown sanding brand.

Any help or suggestions to repair this spot. I don't want to repaint the whole hood. Thank you in advance.

View attachment 55318
View attachment 55317
View attachment 55320
View attachment 55319
 
Honda Enthusiast said:
Dear all,

I am new to this wonderful forum, and also new to car detailing, I detailed a couple of cars with hard paint but first time to work on my wife's Honda Accord. I was sanding a bird drooping on the hood, with 2000 grid with plans to do one pass with 3000 then compound then polish.

I always use 3M sanding papers, however this time I used a product called from auto zone (Finish 1st mini block as seen in the picture, I used the 2000 grid verison), what I liked about it, the block was very small to tackle tiny areas instead of sanding larger areas. I sanded for only 2 minutes only, then found this white spot on the paint. THE SANDPAPER WAS COMPLETELY TORN (SEE THE PICTURE). I didn't use a paint thickness gauge. it was the factory original paint, and I wasn't going to go deeper. I believe I made a mistake by not using a paint thickness gauge and purchasing unknown sanding brand.

Any help or suggestions to repair this spot. I don't want to repaint the whole hood. Thank you in advance.

View attachment 55318
View attachment 55317
View attachment 55320
View attachment 55319
Click to expand...


Another burn through thread:
http://www.autogeekonline.net/forum...ons/108091-cloudy-spot-after-wet-sanding.html
 
thanks for the link, what should be the next step now? I used only 2000 grid for just 1 minute. I used plenty of water but I did around 1 pm, I think the coat temperature was too high. I have no idea what is the LSP mentioned in the other thread and how to apply it ?

Thanks again
 
What was your sanding process that resulted in your sandpaper being torn up like that? Yes, generally doing anything like that in direct sunlight especially on dark paint is the least desirable way of doing it. Japanese paints are generally on the thin side, and starting with 2000 grit is way overkill IMHO. 3000 or even 5000 would have been better. Or, trying some polish or compound first, just to see if it would get the bird dropping mark out.

When you have small spots like that to sand, you can just tear off a small piece of paper and use your finger as the backing plate. You get excellent control over the pressure and sanding area size.
 
I figured out what happened, the velcro system failed and the sandpaper was torn off from the velcro, and I didn't realize that until late. I guess was sanding directly with the velcro attachment of the handle, I can see white material in the velcro of the sanding block. finish 1st brand from auto zone (useless). I sanded other parts with 3m 1500 grit and a transitional 3m sanding block and nothing happened. I choose this system because of it is small size. stay away from the brand folks, I will through it away.





View attachment 55326
View attachment 55327
 
Best bet is least aggressive method first.

Why would you sand first?

That is what likely caused the problem.

That little tool pictured puts a ton of force on the sandpaper.

The grit was 2000 sandpaper plus bird poo = 120 grit.

You ground the paint with 120 grit, that is what happened.

Can't fix burn except repaint.

Next time clean bird poo correctly and then if you have etching polish first.

If more agression needed compound.

If still more wet, sand with 300 grit Trizact paper, compound and polish out.
 
Crispy said:
Best bet is least aggressive method first.

Why would you sand first?

That is what likely caused the problem.

That little tool pictured puts a ton of force on the sandpaper.

The grit was 2000 sandpaper plus bird poo = 120 grit.

You ground the paint with 120 grit, that is what happened.

Can't fix burn except repaint.

Next time clean bird poo correctly and then if you have etching polish first.

If more agression needed compound.

If still more wet, sand with 300 grit Trizact paper, compound and polish out.
Click to expand...

Thanks sir, I tried to compound first using meguairs ultimate compound and an orange pad from CC. that didn't work, then I jumped to 2000 grit sand, you are right I think I should have gone with the 3000 grit first. in addition that little tool made a huge force on a small area of sanding plus the failure of velcro. thanks for your advice. I went to a body shop today, he told me he have to repaint the whole hood. is that right ?? or he can paint this part only, I saw videos on youtube people painting only a small portion of a panel and looks good, but as always picture is not like real life, any opinions? also it is my wife's car, she will kill me (lol)
 
A good body shop can fix for ?

The spot painting is small but they have to clear the whole panel.

I get my whole hood painted for $500.00.
 
One other point if you ever try something like this again... When sanding on a small area like that, one or two minutes of sanding is way too much. You should be sanding in increments of a few seconds and constantly be checking your progress before proceeding with continued sanding.
 
2black1s said:
One other point if you ever try something like this again... When sanding on a small area like that, one or two minutes of sanding is way too much. You should be sanding in increments of a few seconds and constantly be checking your progress before proceeding with continued sanding.
Click to expand...

That explains it probably why it was burnt.
 
2black1s said:
One other point if you ever try something like this again... When sanding on a small area like that, one or two minutes of sanding is way too much. You should be sanding in increments of a few seconds and constantly be checking your progress before proceeding with continued sanding.
Click to expand...

Thank you sir for the great advice.
 
Honda Enthusiast said:
I believe I made a mistake by not using a paint thickness gauge and purchasing unknown sanding brand.

I think you made a mistake by wetsanding in the first place...this should never be first choice, too many threads like this...

2black1s said:
One other point if you ever try something like this again... When sanding on a small area like that, one or two minutes of sanding is way too much. You should be sanding in increments of a few seconds and constantly be checking your progress before proceeding with continued sanding.
Click to expand...

+1 and for all the other great advice in this thread about trying compound first, using finer paper first, etc.
Click to expand...
 
Honda Enthusiast said:
Dear all,

I am new to this wonderful forum, and also new to car detailing, I detailed a couple of cars with hard paint but first time to work on my wife's Honda Accord. I was sanding a bird drooping on the hood, with 2000 grid with plans to do one pass with 3000 then compound then polish.

I always use 3M sanding papers, however this time I used a product called from auto zone (Finish 1st mini block as seen in the picture, I used the 2000 grid verison), what I liked about it, the block was very small to tackle tiny areas instead of sanding larger areas. I sanded for only 2 minutes only, then found this white spot on the paint. THE SANDPAPER WAS COMPLETELY TORN (SEE THE PICTURE). I didn't use a paint thickness gauge. it was the factory original paint, and I wasn't going to go deeper. I believe I made a mistake by not using a paint thickness gauge and purchasing unknown sanding brand.

Any help or suggestions to repair this spot. I don't want to repaint the whole hood. Thank you in advance.

View attachment 55318
View attachment 55317
View attachment 55320
View attachment 55319
Click to expand...
Bought that before the paper is garbage.But the. Nifty little handle I still have.
 
If you REALLY struck through, wouldn't you see the paint color on the pad?
 
-Yes, you have burnt through the clear coat and base coat, what you are seeing in that spot is primer.

-Yes, the area can be spot refinished by a competent paint technician for a couple hundred dollars.

-The white residue you see in the velcro hook&loop is not from the sandpaper, it is dried up clear coat slurry (the dried up remains of the clear coat that was sanded off the vehicle)

-As others have said, on a spot that small a minute or two is much too long of a time to be sanding, a couple of seconds or strokes at a time is all that is necessary

-Also bird droppings contain Chitin, a natural chemical that is acidic to automotive paint, if left on too long in hot sun it will thoroughly etch through paint and sometimes it can leave little spots that look like rock chips that are effectively etched down through to the primer or substrate.
 
JKDesign said:
-Also bird droppings contain Chitin, a natural chemical that is acidic to automotive paint, if left on to long in hot sun it will thoroughly etch through paint and sometimes it can leave little spots that look like rock chips that are effectively etched down through to the primer or substrate.
Click to expand...

yeah, that's why it's important to get the bird chit, I mean bird chitin, off as soon as possible :)
 
JKDesign said:
-Yes, the area can be spot refinished by a competent paint technician for a couple hundred dollars.
Click to expand...

A spot repair is not a proper repair. A reputable shop will spot in the color and blend out from there but the whole hood needs to be cleared.


OP. I strongly suggest going to a reputable body shop to have the repair done. Trying to save money on something like this will often end in only more damage to the vehicle.
 
Here's the picture...


55317d1488412269-white-marks-after-wet-sanding-2000-grit-i-think-i-burned-my-paint-img_5322.jpg



Yep... looks like you burned through to the primer...



:)
 
You must log in or register to reply here.
Back
Top