Cutting and Buffing Questions

[eldubb440]

That‘s why I start with 800 on a block, you need something thats going to actually cut and level the waves and peel. Seems anything over 1500 won’t really cut or shape anything. Using a sponge isn’t helping either. You’ll get all the junk out of the paint but you won’t straighten the top layer.

I also aggressively knock down dust nibs with 800, anything finer kinda glides over and leaves a little lump.......they need to be cut, not smoothed over

 

[eldubb440]

bet y'all can't guess what I was doing today

 

[JR_Charger]

I've been using 800 to get the orange peel out. I had a section I needed to go over again with 800, which I did last night. I had a piece of scrap plywood sitting around that was a good size, so I used that as a backer.

 

[JR_Charger]

What foam pad should be used after sanding to 8000? What compound?

I got up to 2500 on the roof last night and, if you back off and look at it at an angle so the scratches aren't apparent, the paint is shinier than it's ever been. I bought the car fresh after a new paint job too (but it was MAACO and obviously no cutting and buffing had been done or they would have cut through the dust they painted over).

I'm using the piece of plywood to back the sandpaper, and soaking the paper in water with a little dish soap, and that works much better than the sponge.

 

[69L48Z27]

What compound? I use the 3M Perfect-it line. Compound, polish, ultra fine polish. Three buffing steps, three pads too. You can use the foam or wool to compound. If you want to get to the point with compound use wool, just be careful. Watch the heat.

 

[JR_Charger]

I like using the 3M Trizact discs with a foam pad on my D.A. I use 1500, then 3000, then
5000, then 8000grit wet as per their instructions. When done, you don't need to cut much,
you only need to use their special polish. The pads last a very long time as long as you keep
them wet while using. At the cost of paint and labor, you don't want to screw it up now! Check
out the 3M YouTube videos. You'll be amazed

I'm sanding to 8000, so what I need is the "special polish."

I may try the Perfect-It system on some other cars I've got, later on.

 

[JR_Charger]

Who wants to recommend a post-8000 grit polish?

 

[zyzzyx]

3M 33039 Perfect-it 1 step finishing polish and an 8" PN33035 foam finishing pad.

 

[JR_Charger]

8"? My buffer only likes 6" but I guess that'll be fine too.

 

[JR_Charger]

I've sanded to 8000. I've got a 6" 3M Perfect-It foam pad. That will work on the bigger areas, but what about areas that are less than 6", like the dutchman panel and the rear window frame -

How do you treat edges? How do you clean/store foam pads?

 

[69L48Z27]

Use the same buffer/pad to do it all. Just have to watch your edges. Put your hand on the panel to see how much heat you’re making.

When you wrap up you can wash the pads in the sink with some Simple Green. Rinse very well and wring them out. Once complete dry put them back in the bag they came in.

 

[JR_Charger]

My edge paint seemed awfully tough, until it didn't . . . I've got some spots that will have to be redone, but I didn't expect to avoid the "learning experience."

 

[JR_Charger]

Is it possible to tell what grit a scratch is?

I polished part of my roof today - looked amazing, until I tried a different angle and it turned out there were sandpaper scratches that hadn't been sanded out. I moved over to a b pillar and tried a compound pass, but the compound and pad combination (3M Perfect-It PN33035 pad and Meguiar's GR17216 compound) wasn't getting the job done either.

I'm also getting a slight fogginess in the paint, although it still has that wet look, it is like the color is slightly lighter. It looks like the DA put it in. I'm not sure what is going on - maybe it isn't serious.

The potential for this to come out good is there. It's glossier than most of the paint I see on the road.

 

[1967coronet]

Is it possible to tell what grit a scratch is?

I polished part of my roof today - looked amazing, until I tried a different angle and it turned out there were sandpaper scratches that hadn't been sanded out. I moved over to a b pillar and tried a compound pass, but the compound and pad combination (3M Perfect-It PN33035 pad and Meguiar's GR17216 compound) wasn't getting the job done either.

I'm also getting a slight fogginess in the paint, although it still has that wet look, it is like the color is slightly lighter. It looks like the DA put it in. I'm not sure what is going on - maybe it isn't serious.

The potential for this to come out good is there. It's glossier than most of the paint I see on the road.

You have received some good advice from guys that do this near every day.
I am late to the party , mabey reading to fast through the posts. I did read ( macco) so I have to ask is this a base clear job or a single stage ?
Please retire the plywood block. A regular rubber 3m block will be best for hand work.
The foggy areas you mention kinda raise a red flag. If this is a base clear job you may be down to the base ? That or it was sprayed with to much air pressure and you have some air fog / bubbles in your clear.
These areas of fog you mention .. clean them up , get a good light on them from the side and get a couple pics. For us.

 

[69L48Z27]

Is it possible to tell what grit a scratch is?

I polished part of my roof today - looked amazing, until I tried a different angle and it turned out there were sandpaper scratches that hadn't been sanded out. I moved over to a b pillar and tried a compound pass, but the compound and pad combination (3M Perfect-It PN33035 pad and Meguiar's GR17216 compound) wasn't getting the job done either.

I'm also getting a slight fogginess in the paint, although it still has that wet look, it is like the color is slightly lighter. It looks like the DA put it in. I'm not sure what is going on - maybe it isn't serious.

The potential for this to come out good is there. It's glossier than most of the paint I see on the road.

You got the 3M pads but not the compound or polishes? I tried to look up that Meguiars part but didn’t find it. All these companies have ‘systems’. No idea what result you’ll get mixing stuff. I don’t know any shops that use Meguiars to compound and polish. All shops that I’m familiar with use the 3M stuff. That pad is a polish pad, you need a white compound pad or wool on your first step.

Take some good pictures like suggested. Sounds to me like you‘re not cutting with the compound.

The bottle should say what pad you need for that product. 3M is three pads, three bottles, caps and pad colors match. White top, white pad etc.

 

[JR_Charger]

Let's focus on the scratches first. Is there a technique for figuring out what grit a scratch is? Maybe I should pick a spot and work down from 2000 grit until they come out?

 

[eldubb440]

obviously each step is supposed to eliminate the scratch from the previous step, so it is possible you are seeing 800, 1000, or 1500 scratch from earlier in the job

I have never depended solely on a foam pad, but never took a job out to 5 or 8000 either...... a little slow wool pad action before foam always gets me where I need to be, especially near the edges and on the points where I do with 2000 by hand

if you think you went through the clear, put a little polish on a white paper towel and rub.......hopefully no color comes up

 

[JR_Charger]

It's single stage paint.

 

[1967coronet]

It's single stage paint.

Ok, now that we know that it takes the burn through the clear out of the mix.
All I can do is pass on my method for cured single stage.
Hard rubber block , flex rubber block and yes as mentioned before a piece of paint stick.
For someone knew to this I would start you off with 1200 or 1500 wet and a bucket of clean water. Few clean rags to wash / clean the surface as you work.
I piece of grit / nib trapped under the paper will scratch things. Working by hand you will feel this right off, were a da will just grind away.
1st cut I do by hand , complete car.
Start at the rockers and work up. Everyone gets lazy on the bottom 12 " around the car so start there while your all happy and enjoying it.
Like eldubb and others say , watch those peaks and edges, dont burn though , keep clean water.
After the 1st complete sanding wash the car and dry it, you will find areas to hit again, you want all peel and nibs gone, complete smooth surface.
Now go to the trizac pads and water start low and work up, 1500 ,then 3000, wash car in between. Once you can read a dollar bill serial number all over in the reflection your ready to buff, follow directions of the brand as far as pad type and speed, again watch the edges.

Worst thing you can do is start hopping around with different grits ect. You loose track of were your at on each area.
Your wet sand and buff needs the same care and cleaning as the paint job.

 

[zyzzyx]

The reason you can't find alot of info or a shop that uses Meguires, is that it's a consumer product,
not a professional product. 3M does alot of R&D for body supplies.