Wet Sanding goof - please advise

[MaxMarkham]

Hi all. This is my first post. Hope I am submitting it to the correct forum.



I had some over spray that the clay bar refused to remove. I tried polishing it off with a yellow cutting pad and a polish good for up to 1500 grit swirls, but it wasn't budging.

So I thought I'd try some light wet sanding on the area.

The goof: I had some 800 and 1500 grit paper side by side and grabbed the 800 by mistake.

No surprise that my 3M compound for 1500 grit scratches didn't help remove my 800 grit sanding job. The area in question is about a 1x1 foot area on my trunk (black car).



I'm trying to figure out how I should approach undoing my 800 grit fiasco?

I have my own ideas, such as just working my way up to 1000, 1500, etc... but wondering if this is the correct approach, or if by sanding with a 800 paper

it's too late to reverse?



Thanks for any help you can offer.

 

[motobuild]

Pics?



.....

 

[MaxMarkham]

Pics?



.....

I didn't think pics were necessary, but if they really are I can snap them when the sun comes up and post back.

Any thoughts in the meantime would be appreciated.

 

[Todd@RUPES]

Hi all. This is my first post. Hope I am submitting it to the correct forum.



I had some over spray that the clay bar refused to remove. I tried polishing it off with a yellow cutting pad and a polish good for up to 1500 grit swirls, but it wasn't budging.

So I thought I'd try some light wet sanding on the area.

The goof: I had some 800 and 1500 grit paper side by side and grabbed the 800 by mistake.

No surprise that my 3M compound for 1500 grit scratches didn't help remove my 800 grit sanding job. The area in question is about a 1x1 foot area on my trunk (black car).



I'm trying to figure out how I should approach undoing my 800 grit fiasco?

I have my own ideas, such as just working my way up to 1000, 1500, etc... but wondering if this is the correct approach, or if by sanding with a 800 paper

it's too late to reverse?



Thanks for any help you can offer.

Max here is the problem (with out any help of knowing your technique, how much you sanded etc).....



If you made more then several passes over the paint or used a lot of pressure, you are going to have already removed a large amount of clear coat. You are going to have to remove more inorder to level out the scratches, so here is your best and safest bet (IMO).



Use a firm sanding block so you can try to focus only on the "high". Start with 1000 grit (let it soak in a bucket of water for 15 minutes) and sand in the opposite direction that you did with the 800 grit. So if you went up and down with the 800, sand with 1000 left to right. Only make a couple light passes (keeping the surface wet and the paper clean), then wipe dry and inspect. Work slowly and precisely until all the 800 grit marks have been replaced by the 1000 grit marks (should be easy to see since they run in opposite directions).



Remember go as light as possible and do go any further the necessary. As soon as the 800 grits are removed, switch to the 1500 grit, this time going in a direction opposite from the 1000 (the same as the 800). Proceed very cautiously until all the 1000 grit marks are removed.



I would continue this up to 2000 grit then finish with Meguiars Unigrit 2500 sand paper. If you have 3000 grit it woud be a good bit to use this as well, to get the surface as smooth as possible before polishing.



Good luck and understand you might have comprimised the clear coat already, so do your best to proceed. Take your time and you should be okay.

 

[MaxMarkham]

Thank you. I appreciate your guidance on this. Here are some shots of the over spray before, and when I stopped after my first *few passes trying to remove it. I say 'few' because you mentioned not knowing how far I took it before I stopped.

I will also note I tried to use the orbital on it after sanding with a light compound.

I guess as you say, I need to just continue the process and I'll start to see some of that haze lift (hopefully).

 

[ABQDetailer]

This is no big deal bro.



Just like compounding/polishing when you wetsand you need to use each step to remove the previous steps scratches/marks. So use 1000 to remove 800, 1500 to remove 1000, 2000 to remove 1500 marks, etc. etc.



Most good compounds will remove 1500 sanding scratches so you don't have to go above 1500 if you don't want to. Anthing above 2000 will just make your compounding step easier/faster.



I would just hit it will 1000, 1500, then 2000. Then compound and polish and you're done. As long as you didn't wetsand off all of the clearcoat then you'll be fine.

 

[MaxMarkham]

This is no big deal bro.



Just like compounding/polishing when you wetsand you need to use each step to remove the previous steps scratches/marks. So use 1000 to remove 800, 1500 to remove 1000, 2000 to remove 1500 marks, etc. etc.



Most good compounds will remove 1500 sanding scratches so you don't have to go above 1500 if you don't want to. Anthing above 2000 will just make your compounding step easier/faster.



I would just hit it will 1000, 1500, then 2000. Then compound and polish and you're done. As long as you didn't wetsand off all of the clearcoat then you'll be fine.

Yes, that is exactly what I ended up doing anyway. The only thing is, after 2000, and then following it with a compound, there is still a haze. It's a vast improvement from the first pictures above, but not what you and I would consider 'finished'.

So what I'm wondering is this... does it makes sense to go backward a couple of steps, to say... 1500 and then 2000 a second time and try polishing out with compound again, or should I back off of the sandpaper now and just compound the hell out of it?

I just feel the compound isn't strong enough on it's own to lift the remaining haze.

I'll add more pics of the current stage later on today, but feel free to respond without waiting for them.



As always, thanks for your input.

 

[ABQDetailer]

Yes, that is exactly what I ended up doing anyway. The only thing is, after 2000, and then following it with a compound, there is still a haze. It's a vast improvement from the first pictures above, but not what you and I would consider 'finished'.

So what I'm wondering is this... does it makes sense to go backward a couple of steps, to say... 1500 and then 2000 a second time and try polishing out with compound again, or should I back off of the sandpaper now and just compound the hell out of it?

I just feel the compound isn't strong enough on it's own to lift the remaining haze.

I'll add more pics of the current stage later on today, but feel free to respond without waiting for them.



As always, thanks for your input.

What product are you using to compound, and what type of pad?



I can remove 2000 wet sanding marks with a LC orange pad and CG 1500 diamond cut.



I guess I'd have to see pics to see what you are saying about the haze though...

 

[bwalker25]

Max here is the problem (with out any help of knowing your technique, how much you sanded etc).....



If you made more then several passes over the paint or used a lot of pressure, you are going to have already removed a large amount of clear coat. You are going to have to remove more inorder to level out the scratches, so here is your best and safest bet (IMO).



Use a firm sanding block so you can try to focus only on the "high". Start with 1000 grit (let it soak in a bucket of water for 15 minutes) and sand in the opposite direction that you did with the 800 grit. So if you went up and down with the 800, sand with 1000 left to right. Only make a couple light passes (keeping the surface wet and the paper clean), then wipe dry and inspect. Work slowly and precisely until all the 800 grit marks have been replaced by the 1000 grit marks (should be easy to see since they run in opposite directions).



Remember go as light as possible and do go any further the necessary. As soon as the 800 grits are removed, switch to the 1500 grit, this time going in a direction opposite from the 1000 (the same as the 800). Proceed very cautiously until all the 1000 grit marks are removed.



I would continue this up to 2000 grit then finish with Meguiars Unigrit 2500 sand paper. If you have 3000 grit it woud be a good bit to use this as well, to get the surface as smooth as possible before polishing.



Good luck and understand you might have comprimised the clear coat already, so do your best to proceed. Take your time and you should be okay.

good solid advise there from someone who's work I admire.

 

[MaxMarkham]

What product are you using to compound, and what type of pad?



I can remove 2000 wet sanding marks with a LC orange pad and CG 1500 diamond cut.



I guess I'd have to see pics to see what you are saying about the haze though...

I've been using a LC yellow pad and a PC 7424 with 3M compound. I also tried Menzerna Final polish, and Meguairs #9. All rated good for 1500 grit swirls. And they weren't cutting through the toughest parts.

I'd say 95% percent of the haze was lifted and polished up quite nicely, but I still had a couple of stingy areas that just wouldn't go away. This is why I was asking if I should backtrack and do some more sanding.

Oddly enough, before I started sanding I pulled out some old ScratchX I had lying around and applied it by hand, and it tackled those tough areas the others weren't cutting.

Does that make sense?

I'll take some more pics of the progress later today.

 

[qwertydude]

I've already posted that even 2000 grit sanding on ultrahard aircraft clear can be removed with M105 and just a coleman 6" with wool pad. I went 1000 to 2000, didn't have any 1500 but I just went over the 1000 areas twice, once vertical and once horizontal strokes. After polishing I had no swirls or haze whatsoever and a razor sharp relection. Those areas shouldn't even be a problem.