Wet sand or emery?

[sbddvm]

I just finished polishing some cast aluminum parts with 420 greaseless and then hit one area with a 3200rpm drill, 4" spiral sewn, and some emery. The finish is smooth to the touch and has a decent reflection that is without major scratches or waves, however it does have a slight orange peel look to it. Can this be improved? Should I step back to some 600 or 800 grit sanding, then finish up the emery stage, or continue on to tripoli?

btw - What grit is emery and tripoli equivalent to?

[jrow]

sbddvm,

Originally Posted by sbddvm

The finish is smooth to the touch and has a decent reflection that is without major scratches or waves, however it does have a slight orange peel look to it. Can this be improved?

Yep! If you have a flat surface use a sanding block and wet sand it. If not, then you will have to get something that will contour to your surface, and wet sand.

John

[sbddvm]

Originally Posted by jrow

sbddvm,


Yep! If you have a flat surface use a sanding block and wet sand it. ...
John

What grit would be the stopping point for the wet sanding before continuing with the emery? What grit is emery? I don't want to go too far just to step back with the emery.

Thanks

[jrow]

Originally Posted by sbddvm

What grit would be the stopping point for the wet sanding before continuing with the emery? What grit is emery? I don't want to go too far just to step back with the emery.

Thanks

Try wet sanding with 400 grit and see how it polishes. If its not to your satisfaction then try 800 - 1000 grit, it all depends on the aluminum! Don't know what grit size is in emery polish.

John

[pickleboy]

Originally Posted by jrow

Try wet sanding with 400 grit and see how it polishes. If its not to your satisfaction then try 800 - 1000 grit, it all depends on the aluminum! Don't know what grit size is in emery polish.

John

emory starts around 400-500 grit. if you sand above that then start out with tripoli.

[sbddvm]

I've been using a 3/8" 120V, 380 watt, 3.1 amp, 3000rpm drill with 4" wheels for my polishing. The greaseless stages went just fine. The parts had a slight orange peel look after 400 greaseless but I was able to clean that up by wet sanding with 400/600/1000. After varying methods of buffing with emery, tripoli and liquid white rouge, I have not been able to get the finish I was looking for. I get a good mirror reflection like expected, however in the right light you can see fine scratches. I see them following the emery/tripoli/ or white stages. I've skipped emery and used tripoli; I've used emery and skipped tripoli followed by liquid white rouge and the scratches are still there. The scratches will change direction based on last direction of buffing so I know that they are not from the sanding.

After searching the forum database, I found that this is not an uncommon problem when poishing aluminum, but I never found a definitive list of potential causes. My questions are, is this normal for aluminum, or is there a problem with my buffing? Are the scratches due to lack of heat, lack of wheel speed, too much/little pressure. Will a 6" wheel work with my drill and will that make a difference?

BTW - I am cleaning the parts between steps and I do not believe my wheels are contaminated.

[mpierich]

<<Are the scratches due to lack of heat, lack of wheel speed, too much/little pressure.>>

My theory is that it's due to excessive speed - no matter how soft the wheel is, it's slapping the metal too hard.

I took the summer off but will be back polishing soon. As soon as I get a slower motor I'm going to try that for the last few steps on aluminum. I'll post the results here.

[pickleboy]

Originally Posted by mpierich

I took the summer off but will be back polishing soon. As soon as I get a slower motor I'm going to try that for the last few steps on aluminum. I'll post the results here.

welcome back bro long time no read. hope you had a nice break.

[mpierich]

Hiya Pickle!

Yep...I needed the break for sure...spent all winter: come home, in the shop, eat supper, in the shop, bed. Almost burnt myself out. A summer of ridn' my scoot and a couple of old-school biker parties fixed me right up, LOL...

I did work on equipment...built a swivel stand for my big flexible shaft and motor, now I can go at different angels without kinking the shaft. Also about to put together my 6x48 belt sander with foam rollers. Got all the parts made, just need to get it running and figure out how to make it adjustable so the belt doesn't walk off the rollers. If I get it working I probably won't need my expander wheel anymore, let me know if you need one - I'll prolly let it go cheap.

[pickleboy]

Originally Posted by mpierich

A summer of ridn' my scoot and a couple of old-school biker parties fixed me right up, LOL....

sounds kinda like my summer. been a little slow but starting to pick back up. and you gotta love the biker club parties and pig roasts.

Originally Posted by mpierich

If I get it working I probably won't need my expander wheel anymore, let me know if you need one - I'll prolly let it go cheap.

for sure i will be interested just let me know. i am toning down on the polish work since the powder is picking up. but i will always be doing some.