why brown before white polishing aluminum? PRO'S PLEASE READ

[insomniac71]

i've been reading alot of posts and dont understand why brown before white. right off caswell's site this is the discriptions of the 2 different polishes. according to the discriptions of both it seems to me that you would use the white(light cut for hard metals) then brown(polishing soft metals) for polishing aluminum. after reading the discriptions this is what made the most sense to me. can a pro polisher explain why everyone says brown before white, just doesn't make sense to me??
1.(brown)A tripoli compound, known well for its general purpose use for buffing and polishing on soft metals such as, brass, copper, aluminum, pot metal.

2. (white)This compound will cut lightly, bringing most harder metals to a brilliant shine. Designed for polishing chrome and nickel plate, stainless steel and ordinary steels.

this is how the compounds go:
1: black is the work horse to get you a nice semi shine
2: brown is like a plow it get's you part to a nice shine
3: white it bring's your part to a high luster

kind of dum way to put it .... but the white is most less a polish .. the brown still is a cutting compound .. the white will bring you part ot a mirror finsih

[skiddz]

I'm no "pro", but have changed my polishing technique to avoid black on soft metals entirely.

For steel I use:

black/sisal or black/tight spiral (Depends on the surface)
brown/tight spiral
white/loose cotton

for aluminum:

brown/treated vented buff (firm)
green/tight spiral or medium vented buff
white/ flannel

Of course, I wet sand to a minumum of 400 before the parts ever touch the buffing wheel.

My results have been excellent using these methods with either material.

[andrews57chevy]

Is this the way to go for an aluminum radiator, wet sand , then buff with brown & white ? What gritt should I start with ? Radiator is new !
Is the starter kit from Cadw. sufficent for the job...
thanks

andrews57chevy

[samtgallagher]

i go from black on sisal or sewn spiral (depends on surface) straight to white on sewn spiral looks like this

[cjlee]

well iam still learning everyday but what will work on some wont work on others..sometimes i use emery then white then sometimes i use stainless then white..you have to try a spot on each part your polishing..good luck.cj

[andrews57chevy]

Originally Posted by samtgallagher

i go from black on sisal or sewn spiral (depends on surface) straight to white on sewn spiral looks like this

Thanks for the input, I'll try it in a spot on the back side of the radiator, that will be hidden by the support frame
andrews57chevy

[andrews57chevy]

Originally Posted by cjlee

well iam still learning everyday but what will work on some wont work on others..sometimes i use emery then white then sometimes i use stainless then white..you have to try a spot on each part your polishing..good luck.cj

I likewise appreciate your input, I'll try these suggestions out and let you know how it comes out..

andrews57chevy

[84Supra]

I'm with skidz on this one. I've had poor results with black on soft metals. The compound seems to scratch more than it polishes.

some stuff doesn't even like the brown it seems. I did this by going straight to white after wetsanding. They are cast aluminum wheels.

http://forum.caswellplating.com/phot...php?photo=2026

[jrow]

Hopefully I can straighten this out.

The compounds are based on the grit size. With Emory having the coarsest grit and white having the finest grit. The next coarsest would be Stainless Steel, then Tripoli.
What to use on what? Good question! You can use any compound to polish any metal within reason. The softer the metal the finer grit compound that you would use. This would also apply to the buffing wheels that you use the harder the metal the coarser the wheel. In this order; Sisal, Airway, Sewn, Loose and maybe Canton for brass and silver. You also must consider whether the buff is treated or not, which will make it cut better, and should last longer.
Aluminum comes in many hardnesses so you have to experiment and see what will work the best for your particular project.
Emory compound is about 400 grit so I wouldn't sand with anything finer than that before I start to polish.
Greaseless: Start with the finest that you can get, 320, if thats not doing the job within a reasonable amount of time and effort use the next coarsest ETC.
Wet sand or dry sand: Yes, both depending on what you are doing and how easy it is to get into the area that you are trying to sand. If I'm using a flap wheel, obviously I don't wet it, try grinders grease. I wet sand as much as possible using a little Dawn dish washing liquid in water to lubricate the metal. I clean my metal with Acetone/brake cleaner when I change buffing compounds or greaseless compounds. I also wash with Dawn and hot water when needed. The Dawn cuts the greasy compound real easy.
Change buffing wheel when you change compounds, rake often and don't load to much polish on your wheels.
Anyone that polishes has their own way to do things, this is the way I do mine. Hope it helps.

Questions?

John