I think I need a little direction please

[Highly]

OK, I have been working on this polishing thing for awhile and have a couple of questions. I have had wonderful success polishing aluminum things to a very high luster using my electric die grinder and a 2" felt wheel with Tripoli to polish following 400 grit. I have been trying to obtain the same results with my buffer and having a heck of a time getting the 400 grit marks out. I know that I should not have to take a part down to 1000 grit sanding to get a good result, but that's the only way I've managed it thus far. Emory and a sisal wheel gets the 400 grit out, but leaves an underlying texture that subsequent polishing won't remove and the part ends up with micro-sized waves in it like 400 grit with soft edges, and that is after spending FOREVER going from the sisal wheel/emory down to a canton wheel/rouge. It takes me a couple of minutes to get better results with the felt wheel, and I know that should not be the case. Here are some pictures of the result. Both pieces were polished from an even 400 grit dry surface.
A felt wheel finish:

One on the buffer:

[Highly]

I have been trying to use the methods outlined in the Buffing Book, working the part upwards for cutting action, varying the direction of passes, and trying all sorts of things side by side to compare results. I know it can be done, but I am obviously missing something somewhere.

[jrow]

Highly,

It appears to me that you are not buffing out the scratch that were left by the first buffing/sanding prior to changing to a different compound.
Try starting with a sewn buff and Emory compound. Use this buff and compound until all you see is the finish that this buff and compound left. You want all the scratches out from your sanding, it will take a while, depending on how deep the scratches are. Look at it under a strong light or the sun you will be able to tell. After that go to the Tripoli compound and sewn buff, then white and a loose buff. Make sure that you rake your buff often, and don't apply to much compound.
You want to get the the scratches out from your previous buffing before you change compounds.

John

[Highly]

Thanks for the response!
How much pressure should I be using on the part? I don't seem to see any result at all until I am generating a fair amount of heat in the part with what I would call a moderately high pressure. Not enough to stall the wheel, but enough to feel the "point of rigidity" in a spiral buff. How much time would you expect to spend in a flat 3"x3" area in order to remove scratches from an even 400-grit hand sand using a sewn buff and emory? Maybe that will help me gauge my pressure/motion...
Thanks again!

[mpierich]

Originally Posted by Highly

Thanks for the response!
How much pressure should I be using on the part? I don't seem to see any result at all until I am generating a fair amount of heat in the part with what I would call a moderately high pressure. Not enough to stall the wheel, but enough to feel the "point of rigidity" in a spiral buff. How much time would you expect to spend in a flat 3"x3" area in order to remove scratches from an even 400-grit hand sand using a sewn buff and emory? Maybe that will help me gauge my pressure/motion...
Thanks again!

You need the heat for the compounds to work. I try to stay just below the stall point (pressure-wise) - make the motor earn its keep.

Generally, don't use sisal as a shortcut on aluminum. Use a spiral, and replenish emery compound often. Rake wheels often. When you replenish you'll feel more drag, that means it's cutting. Try following emery/spiral with emery/loose - the wheel has as much to do with results as the compound. Wheel speed is a factor as well.

Time spent is meaningless; "it all depends". Rule of thumb: go til you think you're done with a step, and if it took you 5 minutes, go another 5 minutes at least.

Most valuable skill is actually seeing what you're looking at. Move the piece around, move the light around, pay attention to direction of grooves. See with your brain as well as your eyes.

[baz]

jrow has given you good advice , i will add to that ,when you go from your 400 grit to the emery try a different angle so when you look under a strong light by the direction of the cratches you know if they are fro the 400 or from the emery. do the same when you go from emery to the tripoli .
in my opinion sisal wheel might be too much ,i would use a sewn buff.
and yes you have to use some pressure and generate heat but the exact amount ,that will come with practice

[Highly]

Thank you all very much for your advice! I spent quite awhile out in the shop tonight working on this, but kept running around in circles. One facet would improve and another would go to heck. I would get a haze-free polish, but with a fine wood grain texture. I'd go through it again and end up with no texture and a deep haze. I decided that I needed to better define what I was doing. Here's how I proceeded.
First I took a corner of the part and brought it down to a smooth 2000 grit finish by hand using wet/dry 2000 grit paper and WD40. This provided me with an almost polished surface with only 2000 grit scratches in it. The WD40 provides lubrication and produces a black slurry as you work it. The slurry is a VERY fine mix and fills in scratches between strokes acting as a guide coat.
Now that I had a known surface, I began working backwards through the buffs. The idea was to better define what each buff was actually doing. I started with a canton buff/rouge and tried to work out the 2000 grit scratches. When I had it as good as I could get it, I pulled out the 2000 grit paper and began sanding so that I could see what texture I just added, if any. When I had the canton buff working well, I backed up to the loose cotton/rouge and followed the same procedure. This allowed me to really sort out my use of each buff/compound pair. I worked back into the sewn buff/emory and a sewn buff/tripoli as well following the same procedure with 1000 grit and again at 600 grit.
Now that I had a little idea of what I should expect to get out of each buff and compound, I reworked my parts. Here's the result:

It isn't perfect, and there is a haze that shows in direct sunlight, but it is worlds better than where I was yesterday! Very few swirl marks overall. I do think that this valve cover is not homogeneous, however. It is harder in some areas and softer in others. If I work through too many buffs to polish it, then it gets a "peeling clearcoat" texture with small islands that polish very well, and other areas that like to "pock" into a woodgrain texture. It also ghosts slightly where I shaved lettering off of the surface (an edge-view is level, but a straight-on view shows discoloration in the shape of the letters). It is MUCH less noticeable the higher grit I sand to and the less time I spend on the buffs. Guess that's another facet of the art of polishing!
Thanks again!

[mpierich]

Sometimes good enough is...good enough.

Some people claim to achieve a "perfect" finish. I don't believe them.

[jrow]

Highly,

Through out your posts you haven't said what you are cleaning the valve cover with between each change of buffing compounds!
The haze you are seeing may be the result of not cleaning the compound off between changes of buffing compound!
Try this: After you have used a buffing compound and a buff, use some acetone to clean that buffing compound off. Then wash it in some Dawn dish washing liquid and water, then go to your next compound. Use different buffing wheels for different compounds. If your using gloves to buff with, which you should, try taking one of your gloves off and see how hot the metal is. It should be hot to the touch, almost to the point that it will burn you. What I do is move it up toward my cheek and that way I can feel the heat on my cheek rather that taking my glove off. If you still have the haze after the above process try hand polishing using some Mothers Mag wheel polish after you have got the shine that you want.
The valve cover looks real nice.

John

[Highly]

Yes, I am being very careful to clean the part using acetone and a soft paper towel (Kleenex...disposed of each cleaning). I have also taken to using a small toothbrush to make sure there is no compound left tucked under nearby edges and in unpolished areas. The part is then washed in Dawn and dried by compressed air. Buffs are regularly raked and fluffed, and each has the compound used in it written on the face with sharpee. Each one has it's own Ziploc and they are kept in a lidded plastic container. Sounds ana .... I mean overly fastidious, but these buffing wheels make a freaking mess. I lost a crescent wrench in the fluff on the floor.
This part in particular was really giving me issues with the "islands" mentioned above. It looked like chipping clearcoat that had been painted over; very sharp defined edges less than a piece of paper in thickness. The raised areas polished up to a very high luster with no haze and the other areas remained hazy. It seems like the haze may be related to more porous areas in the metal holding polished compound in micro-pores, if that makes any sense. I plan on looking into that as I get the time.
Oh, yeah. We gots to have our gloves and respirator. With a spiral sewn wheel that puppy gets hot. I would not be able to hold onto the part without them. I usually wear disposable latex gloves to keep my fingers clean and relatively tight leather over them. The leather comes off for cleaning but the latex stays on. Cheap, and my wife appreciates the clean hands. I appreciate her continuing to allow me to touch her with them. Win-win situation in my book.
I'll give the mag polish a try. I think maybe I will try heating the part up with a heat gun for a bit and then, using gloves and a clean rag, rubbing it out real good with acetone. If I am right, then the pores should open up and let out some of that trapped compound. Be interesting to see what difference that makes. We get the part hot and beat it silly with compound. Would not be surprised to see some of it deep down in there.
Thank you very much for the compliment! I am proud of it, that's for sure. I'll post pics of the set when they are all done Thanks to everyone for helping me get to this point, as well!