Scratches & Haze

[kenykirschstein]

Well I have read all the stuff on here about mirror like finishes on aluminum and tried a lot but still have a problem. I am polishing 1.5 inch square aluminium tubing. I sand with 150 then wet sand with 220, 360 and 600. I then use black compound with sisal and black with spiral. I find that if I don't use the spiral with black that spiral with red just seems to cloud it up. after the first pass with black and sisal I hit it again with some 600 sandpaper to take out some of the pours. You can see the compound fill in some of the pours and sanding between buffs gets rid of the pours. The black with the spiral then gets the finish really mirror like. I still have problem when I go to the red and spiral and the white and loose with it clouding up. I guess a poor base will prevent it from polishing up like it should with the finer compounds. When I am done I get a great mirror finish but when you look into the metal you see scratches and there is a general haze. If you take black with spiral to a piece of extruded aluminium that has not been sanded it looks like the shine goes all the way through the metal. That is what I am after but I just can't get it, I think there has to be an issue with the quality of the sanding, maybe I am missing something here. Like I said I have read all the posts because people ask this over and over but there doesn't seem to be a clear answer. I am using a 3/4 hp buffer with 8" wheels, I heat the aluminum with lamps to get it warm. I am sure there must be something I am missing. I know that I am not getting the results I should when I use the red and white compound. The finish looks shinier after the black with sewn wheel than with the red or white. I know I am running on but just wanted to make sure I explained everything completely.

[JHFGSX9D]

is your buffer a grinder converted? or is it a true buffer? i was getting these same issues !! instead of hand sanding check out the greasless !! it really makes stuff pick up !! your buffing speed makes big differences too i was using a grinder converted and it was strong enough to buff the compound off i was getting the haziness also !! the sisal if you have a strong enough buffer will get rid of all scratches !!

[kenykirschstein]

It is a true buffer, running at 3750 RPM, with 8" wheel that should be plenty of speed. I looked at the my sanding work last night and I don't think I can improve on it at all. The finished product is smooth with no imperfections and no visable scratches, So I have to believe that the problem has to be in the initial buffing. I looked again at the piece I did and it is really shiny, you can read a newspaper with it and if you look at an angle you can see that the finish is really smooth and highly polished. However when you look straight into the metal you see a slight haze and fine hairline scratches.

[kenykirschstein]

I took some pictures, I hope someone looks at them and gives me some help. I recorded each step. The first picture is after the sanding...

as you can see I think the sanding is pretty good. The next picture is after the first buffing with black and sisal. It worked pretty good but I could probably get a little better results.

The third picture is after the buffing with black and spiral wheel. It looks pretty good, could work and get it better, still some haze down in the metal but overall a pretty good finish.

The last picture is after buffing with brown and spiral wheel. As you can see it dulled the finish and left a haze to the metal. Not what I expected, it should have given me a deeper shine and hopefully gotten rid of some of the haze. Instead ti was duller and hazier then with the black.
What gives...
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[tomg552001]

How many amps is your buffer? Are you using the proper cutting action? Also, use sisal with black, spiral sewn with brown, and loose with white. 75% of the polishing should be done with a sisal and black compound. Looks to me you're not spending enough time on the sisal/black. Good luck.

[kenykirschstein]

My buffer is about 15 amps, doesn't bog down with the sisal but will bog down with the spiral if I apply enough pressure. With the sisal I can get the bar pretty hot. I do use the prscribed cutting action.
I can understand your comment about time with the sisal black and I will try that. What it doesn't explain is the reduction in shine with the spiral brown. You can see a definite decrease in the shine between the spiral black and the spiral brown. I used the spiral black because when I trieds the brown right after the black sisal it looked like ****. My thinking is that even if the work doesn't look that great after the sisal black, it shouldn't look worse after the spiral brown, just won't look like it could. I do have loose white but what would be the point if the brown doesn't work.

[bhhodges]

it sounds to me in your posts that the brown is your major problem so it sure wouldnt hurt using the white instead of the brown maybe even the green as well.


bill

[kenykirschstein]

That's a classic answer, if it hurts don't do it. The point being is that the brown should produce a better finish than the black. It doesn't so either I am doing something wrong or there is something wrong with the material. I have done a little experimenting with the white and I suspect I will have the same problem.

[tomg552001]

If you do not cut and color enough with the black, going to the brown defeats the purpose. The scratches will be too deep, and the brown isnt strong enough to cut them out. It's like going from 80 grit sand paper, right to 320. It will take forever to get the 80 grit scratches out unless you progress slowly. The scratches just fill up with compound and get stuck, thus not polishing. I'd spend a good 20 -30 minutes on black and sisal both cutting and coloring motions. Id suggest going to white with loose and skipping brown. I to never had good results with brown. Good luck.

[skiddz]

I've had similar problems with brown on a well used spiral wheel. No amount of raking would help so I just got more wheels. I think tom is on the right track with his sisal/black advice. I've changed my technique to reflect his advice. I do the cut direction only until the luster is really coming on, then color with a firm hand. IMO if the part isn't getting a bit uncomfortable to touch, the work just isn't getting done. Heat is my friend! I've also found that a *little* compound often is more effective that loading the hell out of the wheel every 10 minutes.

I still do the brown steps in the same manner, but I make sure the wheels are clean before I start. Makes the wheel life shorter, but saves me some frustration.

The white I only color with. I don't get very good results when I try to cut with it.

I think polishing is like inventing. There's a lot of trial and error involved until you come up with a method that produces good results.