Newbie (somewhat) buffing question =)

[TonyStarks]

Hello everyone! I thought I would stop in and ask a couple of questions since you all have been so helpful before! (Thank you!)

I'm having a little trouble finishing up buffing an item that I've made out of copper. I've done all of the sanding and early buffing stages and am right at the upper end of the buffing spectrum. I'm not a total buffing newb . . I've had a lot of success with smaller items. But this is really the first item that I'm buffing that is quite a bit larger than the buffing contact surface so it's much harder to get a uniform surface.

I am trying to get the ultra small scratches out caused by the the last level of buffing I did which was with a green bar that I DID NOT get at Caswell. It's a green bar composed of superfine Chromium Oxide. It is a step beyond Tripoli. And I'm trying to figure out where to go next to get the fine scratches out.

I just want to add ahead of time, that while I'm learning buffing, I am quite familiar with the process of sanding-- so, the scratches you see in the pictures below ARE NOT scratches left by sanding. They are completely left by the buffing compound I last used and I know that FOR SURE.




SECOND QUESTION -- In the below picture, I circled some of the small black specks that I get with some buffing compounds. Now I've heard talk about them in many places but I want to know what exactly they mean. I've read that it means you don't have enough compound on your wheel and I've read that it means you have too much compound on your wheel. I think I've read a few other things to. So, how exactly do I determine the reason that I'm getting the black specks of compound?


**Just a note: I am well aware that in this photo there are scratches going in different directions. They are ALL scratches from the same buffing compound and NOT from previous levels of buffing/sanding. I've been experimenting with various wheels/directions/pressures to get rid of the scratches

As always, THANK YOU SO MUCH for the help; it's always so very appreciated!

Thanks everyone!

[TonyStarks]

Let me just add that while the last compound I used was not made by Caswell, I am interested in what products I should order from Caswell to solve the problem described above.

As mentioned above, the last compound I used was a green bar of "superfine" Chromium oxide that is supposed to be finer than Tripoli.

Thank you in advance for any help . . I'm really stuck here and any help would be truly appreciated

[sclark0106]

I know those black specks all to well. I will start by saying that I have never tried to polish copper, only aluminum. I had the exact same problem with those specs, and spent many many hours reading the forums and trying different things. One thing for certain, they can ruin a polish job in a hurry if your not careful. I too heard the "to much/to little" compound story a dozen times. I think what it boils down to is that everybody develops their own way to buff to get their own desired results.

If you put more compound on the wheel, it will indeed grab that dried compound and lift it off. If you get way to much compound on the wheel, there's simply just to much for the buff to hold, and it's gotta go somewhere. Usually there are large streaks of compound, not the tiny specks you have, when the wheels are overloaded. (that's my experience, anyways)

If you have to little compound, there's not enough compound to keep cutting, and heating, and specks will dry and stick to the part. Exactly what your showing.

Now, I bet that you have had specs at times and pressed a bit harder on your wheel, and some times they come right off. This usually happens because the added friction heats those compound specks up enough to remelt the binder, and away they go. However, the added pressure sometimes leaves extra, or deeper scratches, or an uneven surface if you really get wild with the pressure.
This is what I have discovered to work for me, your mileage may vary...
Heat your part up so the compound will not even think about drying. I use a small hand held propane torch. Those black compound specks would not be there if they could not dry and stick. You will also find that much less force is needed when your buffing, and your surface will have allot less scratches in it. I usually get great result with the white compound, but there are still small micro scratches in the surface. If I then use the blue, it really makes a stunning mirror surface. Keep in mind though, the blue is much more dryer than the others, and you really have to be certain to keep the part well beyond the melting point of the binder.
Heck, there's no cost to try this method, so get that part really hot, and give it a shot and see if it works for you.

[Rasper]

Tony,

Without a reference object in the photos I can't tell whether the copper is two feet wide or an inch wide. If it's two feet wide you don't have scratches, you have gouges, so I guess it's a bit more narrow than that, but whatever width, those look like pretty serious scratches. Have you checked your compound for grit?

I have polished some copper and have found tripoli and then red rouge to work perfectly. That chromium oxide is too hard for copper I think. (Copper is soft.) I use that for stainless.

R

[TonyStarks]

Sclark, thank you soooo very much for your detailed response about the black specks. That was exactly the type of answer I was looking for . . really clarified that for me better than anything else I've read so far. Thank you so much!

Rasper, thank you for taking the time to respond! I apologize for not clarifying how big exactly the area you are looking at in my pictures really is . . that's an important detail that I sort of left out . . oops The piece is just a square copper plate that I cut a square out of in the middle. So the edges all the way around, as best seen in my first photo is approx. 2 1/2 inches wide.

So, no, it's not a huge piece with massive scratches, thankfully! The pictures probably make the scratches look a bit worse than they really are. I positioned my tripod and angled the camera in such a way to really catch the scratches in the reflection. When you look at it from other angles it looks much better and it's a mirror finish overall; I can see my face clearly and it's a nice flat finish. But those scratches are clearly there from certain angles and they shouldn't be there!

I'll try some white compound and see what happens. The green bar of chromium oxide I used was billed as being a step or two finer than Tripoli. But, I think I'll try the white and go from there.

Thanks again for the help and I certainly encourage anyone else to comment with their thoughts . . . every bit helps!

THANK YOU!

[TonyStarks]

Hello all, and, again, thank you for the continued help! Just posting a small update since having tried some white compound and taking some new pictures that will hopefully give everyone a better idea of what I'm working with and what the problem is.

The finish on my copper piece is a little bit better but not by very much. It's still got the hazy scratches that I'm trying to get rid of.


This is just a zoomed out picture of the entire piece that I'm buffing. It's approx 17 inches long and 9 inches wide. The surfaces being buffed are about 2 1/2 inches all the way around give or take a bit. As you can see, there is quite a nice shine but you can see in certain spots in the light the hairline scratches/haze that I don't think should be there. I will add that I had the nearly the same reflectivity before trying the white.



Zoomed in a bit further and camera a bit closer. Again, you can see that I've achieved pretty good reflection but those scratches are visible when the light hits in the correct way.

continued . .

[TonyStarks]

. . . continued from the above post . . .



So, here I took another picture at about the same camera position an zoom as the previous picture but I focused the lens on the surface of the copper instead of the reflection. It gives a better view of the scratches I'm trying to get rid of. They are a bit better than they were previously but not by much. And they are definitely caused by the buffing; if I buff perpendicular to the current scratches, they will just reappear going in the other direction.

Separate from the scratches that I'm trying to get rid of, you can also see the surfaces general condition that has these pit type marks. The surface of the copper did not look like this until I started buffing with compounds. I sanded by hand up to 800 grit and the surface, close up, did not look so irregular. This surface texture appeared after my first buffing pass. So, maybe that's the way it should be, but I'm not sure. I'd just be happy if I could get the scratches out.



Just another image with the camera moved in closer and zoomed further to give a good view of the reflection I have despite the scratches that I'm trying to get rid of. Maybe haze is a better term . . I'm not sure; I've seen others referring to these light hairline scratches as "haze"

I will add, just in case the question comes up, yes, I do use separate wheels for each type of compound and I'm super paranoid about contamination so If there is contamination, I really don't know how it would have happened.


So, I'm not sure what to do at this point. Do i need a finer CUT compound to get rid of the hazy scratches? Or does a COLOR compound get rid of this? Thanks again, for the help guys!! I really, really appreciate it!

[sclark0106]

I get those micro scratches too with white compound. Not to the degree that your getting, but I'm polishing 7075 aluminum, not copper. The blue compound usually takes care of those fine scratches for me. Keep in mind though, if the blue dries on your part, it's harder than the white, and can damage the surface really easily. It might be a wise idea to practice on something first to get a feel for the way it acts. I have read that adding a bit of flour removes the haze, but personally I have had no luck doing that. It may be that going to a different type buff would work better, or try using a new soft buff without any compound. Keep us informed on what you find that works for you. Good job on the detailed photo's!

[TonyStarks]

Sclark, thanks again for your response! I really appreciate your taking the time to help me out. I'll certainly give your method a try; when you say BLUE bar, are you referring to Caswell's "Blue Rouge"? I just want to be sure about what I should include in my next order.

I have also read about using the flour, but like you, have not seen any results at all from it. I'm sort of confused, as I've read and been told by a few others that using flour will get rid of the hazy scratches . . but it has absolutely no effect when I try it. Am I maybe doing it wrong? I was told to mist the piece being buffed with water and sprinkle it with flour, is that correct? Even with the water, most if it blows right off when I approach the buffing wheel. And if I add a little more flower, it gums up all over the piece and gets stuck to the surfaces.

I should be able to get rid of those scratches correct? I mean, the part as of right now really looks beautiful at particular angles . . but the scratches become really visible at MANY more angles than at which they disappear, so I'm thinking that my finish still isn't quite right. I mean, I think I should be able to look at the item from several feet away and not see hazy scratches in the light? Well, anymore suggestions from anyone on would be great!

Thanks so much for the continued help!

EDIT: JUST WANTED TO ADD THAT THE FIRST PICTURE IN MY PREVIOUS POST THAT HAS THE TWO PICTURES IN IT WHERE I FOCUSED THE CAMERA ON THE SURFACE INSTEAD OF THE REFLECTION , YOU CAN SEE SOME LONG SCRATCH LOOKING THINGS GOING ACROSS MOST OF THE SURFACE. THOSE ARE NOT SCRATCH MARKS, THEY ARE MARKS LEFT FROM THE ACETONE I CLEANED THE ITEM WITH BEFORE TAKING A PICTURE. THE HAZY SCRATCHES I'VE BEEN TALKING ABOUT ARE TO THE LEFT IN THE REFLECTED LIGHT.

[baz]

for the black specs ,usually it is too little compound or loaded buff that needs cleaning but could also be working with too cold of a material if the material has been outside or in a cold place you cou lget that problem