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Orbital sanding marks in clear coat

#1
Hello
I am new to this site and new to polishing clear coat paint.
I have a 72 convertible Merc and tried to make her paint even more desirable. In do that I made it a disaster! I wet sanded with 1000,1500 and 2000 grit. The problem is I guess I got some contaminates while sanding. Not good! You can’t see small orbital marks all over the car! It shine nice but up close it looks bad! Worried about how deep the marks are and how much clear coat I have left to work with. I have sanded a couple edges down to primer. My bad! So I’m worried to try again. I’ve tried the orbital sander then a straight block with sand paper. I’m just sick evertime I wash the car and see all the imperfections. My problem is a watched a few YouTube videos on how to do it and went to town.
My question is how do I fix this issue and feel confident in doing it not reluctant in doing anything more. Thanks
 
#3
Oh it’s from the orbital sander for sure. Small tight circles that stretch out a few inches.
I used the wool but I found it makes a mess! Wool everywhere and a paid $45 for the wool pad!
I’m sure like I’ve read in previous post that some contaminates got in the sandpaper. Or wax build up. I have no idea. But it’s all over. Looks like s#%t up close! Pretty bummed about it and reluctant to try and fix it as I said before I don’t know how much clear coat I have to work with at this point
 
#4
It's a '72 that's been repainted at some point? Clearcoat wasn't around in '72.
You could find a detailer with a thickness gauge to let you know what you have to work with.

Pigtails are a pain. Wet sanding helps to wash debris away. It's messy but effective.

I use a high pressure nozzle to blow all the loose fibers off a new wool pad while it's spinning at high speed. Always outside. Otherwise, it looks like a sheep exploded in my shop.
 
#5
I get exactly what you described when I try and make the sanding discs last longer.
they load up and scratch very quickly.
Keeping a fresh disc on has solved most of that for me.
 
#6
Hello
I am new to this site and new to polishing clear coat paint.
I have a 72 convertible Merc and tried to make her paint even more desirable. In do that I made it a disaster! I wet sanded with 1000,1500 and 2000 grit. The problem is I guess I got some contaminates while sanding. Not good! You can’t see small orbital marks all over the car! It shine nice but up close it looks bad! Worried about how deep the marks are and how much clear coat I have left to work with. I have sanded a couple edges down to primer. My bad! So I’m worried to try again. I’ve tried the orbital sander then a straight block with sand paper. I’m just sick evertime I wash the car and see all the imperfections. My problem is a watched a few YouTube videos on how to do it and went to town.
My question is how do I fix this issue and feel confident in doing it not reluctant in doing anything more. Thanks
Most DA sanding disks are meant to be used dry, maybe if you post which ones you used people could give you good advice.
 

jlcustomz

evil painter
#7
Lots & lots of different methods to achieve what you need here.
Edges are the main place that needs care . even seasoned detailers may simply tape up the edges to avoid contact.
In any situation like this the aim is always to remove as little as possible material for correction. This may mean starting with 3000 or 2000 in a spot, buffing a little to assess the surface & then going back coarser, then finer again. You may choose to just knock down around the worst of the swirls, but not completely for thickness sake if not sure. I HATE to heavy sand & buff anything I did't paint myself.
Contamination can come from many sources, including water out of a faucet.. Some use fuel filters or such on a small hose to drench surface or just spraying from spray bottles.
The more modern way to go around contamination especially in the finer final sanding stages is to use a dry sandpaper , such as 3-m triazt. Haven't personally used it much yet. More pricey than most wet paper, but seeing what the hell you're doing without wiping water & wet paste out the way and not introducing contaminants can be priceless.
Buffing equipment again is an opinionated subject. Old school wool pads can cut faster, which can make a great start in skilled hands, but are much easier to burn through with. Foam pads come in different coarseness for cutting, which need to be picked according to stage of cut you need along with polish type being used. Black waffles are usually the best for final polish stage for final clarity. A lot of new stuff out there now, including denim pads meant to remove some orange peel.
 
#8
I can’t tell you what make of the sandpaper. Just a cheap sandpaper that I purchased from a Canadian Tire store. I was wet sanding with a electric orbital sander. Which I know is wrong but that all I had. My air compressor couldn’t keep up with an air sander. Like I said I’m no professional and nor am I trying to pass myself off as one. Lol all I wanted to do was make an already great paint job look even better. But it back fired
 

EddieF

Top Banana
#9
Honestly, you should do it by hand. I've done a few cars and still don't trust power sanding.
New quality paper cuts quick enough. Leave power sanding clear to the true pros.
 
#10
Yeah
Wish I heard that before I did what I did. I think the worst was watching YouTube a few times and said to myself “I got this!” When I didn’t! Really sick of sanding and polishing. I wait until spring before I atemp to do a redo. I’m about to do a cam swop in a few days so that will keep me busy for awhile. Thanks for all the posts. Just one other thing?
What color foam pads for which stage and the speed per stage? I have the dewalt 7” veritable speed
 
#11
I usually start with wool then use a yellow foam pad with medium cut compound
followed with fine cut or even swirl remover on a yellow or black one.
I usually buff around 1800 to 2000 rpm.
 
#13
the sandpaper makes a big difference. you really dont want to use just any sanding discs. i can buy regular 1500 sanding discs and also buy 1500 finishing film that made for color sanding clearcoat and one will buff right out and the other will be too deep to buff. same grit but finishing film is made to give a very shallow scratch that buffs easy and regular paper is meant to be super sharp so it cuts deep and quick.
 
#14
And that’s probably what happened to me. Instead of buying from a reparable auto paint store I purchased from a store with low prices. Wish I knew this. Thanks for the info
 
#15
The one thing any beginner needs to remember throughout the color sanding /buffing process is that that it can be very satisfying ONCE you get good enough at it. Can't let it whip you.
Thinking back, the last time I had a really bad case of pigtails was near 20 years ago from some color sanding kit I got at a car show. Absolute crap.
Fixed it with some german Festool sanding pads. Similar results to the films Jim mentioned, they cut soft & smooth. In your case, it definitely looks like the cheap paper screwed you.
With compounds, there are your different levels of cut and there is also diminishing cut type compounds such as Meguiars diamond cut. It starts out cutting coarse enough to remove fine sanding scratches, then turns into more of a polishing rouge as it wears. Just another choice. While not the first choice for most professionals for absolute best results, it can give you a little quicker gratification at one time, encouraging you to keep going. Also great for small areas not having to break out & get going 2 different pads & polishes.
 
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#16
Boy it would be nice if we lived close and have you come over and show me the wright way. As it is right now I’m paranoid to touch it because of burning through the clear coat. Thanks you for all your guys advice
 
#17
Another thing to remember.
IT'S JUST PAINT. Once you become one with the true meaning of that, the paranoia will subside. Just leave the average you tube video's alone, gather a little more knowledge & products & proceed a small section of time with caution. There is no one exact right way as much as there is a lot of wrong to avoid.

Even better, see if you can find something else to practice on,crashed parts from body shop maybe. You can bring em back after practice if they want them for scrap. Then you can push the limits without worry & get a better feel for things.;)
 
#19
Another big mistake most people do with Random Orbital sanders is moving
the sander back and forth real fast. The directions for the tool says to move slowly so
the orbits can cancel each other out.
Even woodworking shows on TV show it being done wrong, way to fast.
That's the best way of getting pig tails. Very common misuse of the tool.
 
#20
JC, I've found that my hand speed correlates directly with the spin speed of the tool. I have to conscientiously tell myself to slow.
 
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