Black goo - Buffing old paint

[70Bronco]

I’m buffing the old paint—it’s old and dirty—with 3M rubbing compound and a power buffer. I’m applying with a sponge on the power buffer. When I remove the material with a wool pad, this black goo sticks to the paint. Buffing again just adds black goo (and removes more paint). The only way to get it off is to use a heavy cleaner and serious elbow grease.
Is there a better method?

 

[snakeyes]

 

[70Bronco]

I watched these videos, but none of them addressed my problem. If I missed something, let me know, but I didn't see anywhere that explained my issue or what to do about it.
I searched the internet and didn't find anything and thought maybe somebody here had some experience to share.

 

[2quick]

looks like you cut through the paint on that body line. Not sure there's any coming back from that!

 

[70Bronco]

looks like you cut through the paint on that body line. Not sure there's any coming back from that!

The paint is rough. The Southern California dun melted most of the paint on the trunk and hood a long time ago;-) most of the car had been covered with primer, I wet sanded a lot of that off to expose the original paint.

 

[RT K_line]

That looks pretty oxidized, I think it's past buffing out. But if there is still primer over the paint you need to wet sand some more, 400 600 1000 1500 then if there is any paint left some lite compound. good luck.

 

[70Bronco]

OK, guys, the focus is on the gooey black stuff that gets stuck to the car after buffing. I'm just trying to remove some of the scratches from wet-sanding off the primer. The car will be rough looking when it's done.

The best solution so far has been to use a wet sponge on the buffer and then wipe it off with a towel while it's wet then wash it with a seriously strong cleaner.

 

[RT K_line]

Maybe the sponge type pad isn't the right choice then, I use the corse and fine hair type pads. Cotton I think but not sure.

 

[Mike67]

I'm no body guy but it looks like the wrong type of compound and buffer combo...you probably want a polish or something less aggressive as its wading up and not cutting....

 

[69L48Z27]

Use the compound by hand over the 'goo' and it will likely pick it up.

If your using the 3m stuff that's tan and has a grit to it when you rub it between your fingers, don't. That stuff is crazy aggressive and is worse that 1500 grit paper. I only use that stuff by hand to remove over spray.

 

[69L48Z27]

Detail spray will also loosen it too.

 

[70Bronco]

Use the compound by hand over the 'goo' and it will likely pick it up.

If your using the 3m stuff that's tan and has a grit to it when you rub it between your fingers, don't. That stuff is crazy aggressive and is worse that 1500 grit paper. I only use that stuff by hand to remove over spray.

I will recheck. It’s supposed to be the single stage, common stuff; it’s not the multi-stage stuff. Thanks.

 

[RT K_line]

This is what I used after wet sanding.

 

[Rick62]

This is what I used after wet sanding.

View attachment 523627

Just my opinion, it looks like you're letting the compound get too dry. Try spraying the painted surface lightly with water before buffing.

 

[70Bronco]

Use the compound by hand over the 'goo' and it will likely pick it up.

If your using the 3m stuff that's tan and has a grit to it when you rub it between your fingers, don't. That stuff is crazy aggressive and is worse that 1500 grit paper. I only use that stuff by hand to remove over spray.

I'm using the stuff in the yellow bottle. It's the single stage stuff--not very abrasive. Feels more like liquid wax. Great at putting on a shine and removing light scratches, but doesn't touch deep scratches, which is fine.

 

[69L48Z27]

I'm using the stuff in the yellow bottle. It's the single stage stuff--not very abrasive. Feels more like liquid wax. Great at putting on a shine and removing light scratches, but doesn't touch deep scratches, which is fine.

That's good. The other stuff gets all gummy like that.

 

[70Bronco]

In the end, I think it was the aluminum metal flake coming off and coagulating. Putting a wet sponge on the buffer and lightly going over it followed by wiping it with a towel was the easiest solution. Washing it with a strong degreasing cleaner worked too. Applying buffing compound by hand worked, but required more work. That's the finale.