Fine Scratches & Haze Won't Go Away

[rickt]

I'm finally getting back to the '78 Suzuki cycle engine cases that I started on in the spring. I removed the polymer coating with hardware store paint stripper and got a good smooth finish with tripoli on a spiral wheel. I'm using a 1/2 hp (3500 rpm) bench grinder with 8" wheels.

I read a number of posts about the importance of cleaning the metal when changing compounds, so I throughly cleaned the first engine case with degreaser followed by acetone and finally a good scrubbing with dish soap and hot water. I went one step further and washed my spiral wheels that have only been used with white coloring compound with dish soap and lots of hot water. After everything dried, I put the two 1/2" wheels together and gave it a go. Same result as six months ago - fine scratches and haze when viewed under the fluorescent lights in the workshop. The fine scratches shift 90 degrees when I turn the piece 90 degrees, so I know there are coming from the white compound polishing wheel.

Have I missed something? Anyone have any suggestions for improving the overall appearance of the cycle engine cases? I found polishing stainless auto trim to be much more straightforward than these cycle parts

rickt

[mpierich]

The harder the metal the fewer problems like this, which I guess is why chrome and stainless polish out so nicely.

Since I don't know what previous steps you've taken, all I can suggest is to try softer wheels. Sometimes we focus on the compounds and forget that there is the fabric of the wheel that is also rubbing on the metal. Loose wheels probably do less damage, or even felt might be necessary for a "perfect" finish (if that is obtainable).

If the scratches change direction with this last step, you at least know where to concentrate your efforts at solving the problem. Otherwise they may be from previous insufficient sanding/buffing.

On the other hand, if you take the cases outside, lay them on the ground in the sunlight and pretend you never saw them before, do they really look that bad?