First Cut and buff job. Need some advice.

Discuss anything after that final masking comes off.



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PostPosted: Thu Oct 22, 2020 10:08 pm
Painted my car for the first time. Artic White. Base coat/clear coat. I have a door that I have been working on and I want to get it right before I use the same steps on the rest of the car. The problem is IM GETTING SWIRL SCRATCHES in the finished product and it's also slightly cloudy in the reflection. I'm not sure if the scratches are coming from my DA sander or my Dewalt buffer pads. Here is what I used to finish the door and the order it went in. Again this is my first time and Im learning. I want to find a set up that works for me.

Block sanded clear coat with 800 by hand then 800 on my DA.

Block sanded 1000

Block sanded 1500 then 1500 with DA

Block sanded 2000 then 2000 with DA

Block sanded 2500

Block sanded 3000 then 3000 with DA.

Buffed at 1000 RPM with white 3M pad 05723 and 3M compound 36060

Buffed at 1000 RPM with black ebay pad using 3M 06094 Machine polish.

This took forever, maybe I'm doing it a little over kill but something is causing scratches... Advice on how to fix this and how to proceed with rest of the car would be much appreciated.

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PostPosted: Fri Oct 23, 2020 12:03 am
Wow, that's a lot of effort to put scratches into the paint.

The bottom line is that you simply haven't effectively sanded out the scratching done in some previous step. Which one I'd have no idea but you'll probably have to backtrack a few grits to get the scratches out.

Are the scratches in straight lines, like when you were block sanding? Or are they circular, of similar diameter to your rotary pad? Or are they little squiggles, a few millimetres long?

Try to take some pictures of the damage and post those up so we can try to help you identify.
Chris



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PostPosted: Fri Oct 23, 2020 6:34 am
1st thing i suggest- change sanding directions between each grit and use a guide coat between each grit. dump the da,too.
small pigtail swirls=da marks
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Pigtails_in_Paint.jpg



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PostPosted: Fri Oct 23, 2020 2:32 pm
Are the scratches in straight lines, like when you were block sanding? Or are they circular, of similar diameter to your rotary pad? Or are they little squiggles, a few millimetres long?

They look to be small and circular, my DA is 5 inch. This door is a such I pain. I got a bunch of runs because my gun air filter got plugged up and dropped to 10psi on the last coat of clear, I tried to sand out all 30 of the runs but ended up burning through to the base.. I remember seeing straight scratches in the paint after cut and buffing the first time in the area that did not burn through...

Since then I have scuffed and shot it with new base and 3 more coats of clear. No runs this time but sanded down the clear quiet a bit to remove orange peel only to have swirl scratches all over in the final product.

I'm alittle concerned about sanding more on this door as I already burned through again on a corner using a foam block by hand, it's a small spot the size of a pencil eraser but non the less it burned through and I'm pissed about it but can live with it I guess. I have some other runs in the clear on the car from that mishap but would like to figure out a process before moving on to the rest of the car.



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PostPosted: Fri Oct 23, 2020 2:33 pm
tomsteve wrote:1st thing i suggest- change sanding directions between each grit and use a guide coat between each grit. dump the da,too.
small pigtail swirls=da marks


Yep looks similar to those scratches

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PostPosted: Fri Oct 23, 2020 5:15 pm
Pigtails are caused by a piece of grit getting caught between the paper on the DA and your paint. The grit is usually very large compared to what is on the paper, so the scratches are deep. Flowcoating usually gets rid of them, or you can just continue to buff, using your coarse pad and compound and, of course, checking progress frequently.
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PostPosted: Fri Oct 23, 2020 5:36 pm
on the runs a great way to sand them is to spread glazing putty over them. let it dry.use a hard block backer . that way youll only be sanding on what you want gone.
to keep from burning through edges,tape off edges. then pull the tape when youre up at 1500.
i highly suggest putting the da up and just sand by hand. i personally dont understand why hand sand with each grit then do the same grit with a da.

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PostPosted: Fri Oct 23, 2020 5:43 pm
tomsteve wrote:on the runs a great way to sand them is to spread glazing putty over them. let it dry.use a hard block backer . that way youll only be sanding on what you want gone.


Agree, it's the best method.

tomsteve wrote:i highly suggest putting the da up and just sand by hand. i personally dont understand why hand sand with each grit then do the same grit with a da.


Because, if done right, the DA will leave less scratching than hand blocking. However, the risk of pigtails is high and means that hand blocking is actually the better way to go, even if more work.
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PostPosted: Fri Oct 23, 2020 5:59 pm
Here is a picture with the ceiling light reflecting. You can see the scratches.
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20201023_155351.jpg



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PostPosted: Fri Oct 23, 2020 6:21 pm
I'm also using one good 3M white pad and then I have these cheap $11 set of 4 pads.

Color and Usage:
--Yellow pad for applying a wax or glaze. It has no cutting ability.
--Blue mat provides a slight cutting ability, it can bring your paint to a full shine and prep the clear coat for wax or a glaze.
--Black pad used to remove swirl, mild to moderate hologram, water spots and light defect in the paint.
--Orange pad used to remove heavy scratches and paint defects. Suit for flat clear coating for finishing polishing
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Last edited by Robo999 on Fri Oct 23, 2020 11:16 pm, edited 1 time in total.
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