[klick0]

I used to not do much work with aluminum, but recently i've been cutting a few different pieces of a project, and I kinda want to get some kind of consistent finish to them. I buy mainly from surplus places, so the aluminum finishes vary greatly.

Really i'd like it to look like how I received the k2cnc motor mount, the aluminum isn't polished or anything, it's rough but very consistent and nice looking. It looks like steel wool or some kind of wire brush was used after the surface had been smoothed. Granted, I tried this technique and clearly it is not what they are doing hehe, mine didn't look anywhere near as nice.

So i'm not looking for polished, as that's to much effort, but I would like a consistent "decent" look to my aluminum parts that i'm making.

Currently I sand a bit, then use steel mesh/wool type thing and it seems to be ok, but any suggestions is appreciated

Thanks,
Ross

[hawkeye1]

use use 3M red scotch brite.

[Eurisko]

Try 3M's Scotch-Brite (type A very fine) pads.

Might just give you the finish you're looking for.

[klick0]

I will try that, never would of guessed that one.

Thanks,
Ross

[Alan Wright]

For flat pieces, I was recently advised to try an orbital sander. This produces a very attractive and even finish very quickly. I have only tried 120 grit and intend to try other grits this way as well. I am also using a scotch brite belt on a belt sander after normal grit sanding. Also a nice finish and quick. For curved or small pieces, 3M bristle discs are easy to use in a die grinder, as are scotch brite flap mops. All of these methods give a textured finish (or satin with finer grits). You can presumably proceed on to buffing after any of these, but I have not done this yet.

[neilw20]

Scotch brite belts on a linisher are great.
A bit pricey, but they last well.
Give professional original look on stainless steel also.
Some aluminum types designed for corrosive environments, like roadsigns do not machine well, do net bend well and are horrible to drll/machine/pollish.

[HelicopterJohn]

Hi Ross,

It depends on the size of parts you are working one. I make a lot of small parts for Radio Controlled Helicopters.

I purchased a small table top glass bead blaster from Wholesale Tool for about $200.00. I think it was made by a company called Cyclone. Best money I ever spent. It even came with a little vacuum cleaner for a dust collector. I had to make a few modifications to it but it really works nice for my application.

It only takes a few minutes to do a batch of parts and they all look nice and uniform.

Just something you might want to consider.

John

[Rally]

That is somewhat surprising to me!! I would suppose that the Parts you are making do not have to be very accurate. One suggestion was the Red Scotch-brite ?? That eats aluminum real quick.
Good surface finishes are achieved by correct machining habits, if that is not what you are looking for then I guess it don't matter what product you use. A micro bristol Wheel on a Bench grinder will work similar to the items mentioned above.

[Martin 007]

Weather you polish or bead blast, what would be a good coating to keep it from loosing it's finish to weather ect.....

[LeeWay]

I just looked at one of the aluminum riving knives I made about 5 years ago. This thing is still shinning. It was polished using a buffing wheel and then some Mother's polish. It however hasn't been in any weather.

I use a ROS with the finest grit possible most of the time. Most of my production parts are powder coated, so it really doesn't matter too much. I did use a sand blaster with glass beads for awhile. I still use this for some raw parts. Puts a nice matte finish on it. Glass beads will deform sheet and smaller parts though. Especially when doing only one side. It can really induce a curve in a flat sheet.

There are so many different finishes possible and the steps and results vary widely. If milling the entire block, then I like the look of fresh milled aluminum as long as it's done on an accurate machine. It just screams precision when done right

[ImanCarrot]

For a perfect finish on aluminium Diamond Machine it

Here's one I made earlier.

[HelicopterJohn]

Here is an example of what a friend of mine did with a little polishing effort.

[david90]

Here is an example of what a friend of mine did with a little polishing effort.

What are the steps to get this finish and how long does it take?

[HelicopterJohn]

Hi david90,

My friend who machined and polished those parts lives in Iowa and is a CNC machinist by trade. I am sure the parts you are looking at were produced on a CNC machine. The only thing I know about the process was that he used Eastwood Premium Buffing Composition (emerald green) part # 529-GRN-B Green Brick. This product is available at MSC. Looking at the label it was designed for platinum chrome, and stainless steel to impart a high luster. As you can see it does a really nice job on 6061T6 Aluminum.

As others here would agree, the initial finish of the part depends on what you have to do in the finishing process. Polishing by itself will not cover up a poorly machined part, only shine it.

Personally, I have a motor (industrial strength) with shafts that extend on each end. On one end I have a 8 to 10 inch buffing wheel and the other end I have a scotchbrite wheel. I use the scotchbrite wheel to remove any (minor) imperfections and use the buffing wheel with the above mentioned compound to polish the parts. Polishing small intricate parts will possibly take other tools, steps and methods.

I can get a fairly nice luster on small Aluminum parts in a matter of minutes if the part is easily polished (no internal contours).

John

[fredhh47]

I use a quick process for a "general purpose" finish on a lot of machined parts. When I am done with all machining and general deburring, I use a slow, oily wire wheel to produce a smooth, directionless finish on most any aluminum. A medium wheel, about 6 or 8" in diameter is best, turning at a few hundred RPM. I apply whatever oil is handy, motor oil is OK, to the surface of the part and brush all over the part. The beauty is you can turn the part any which way to get into corners, slots and other details, without leaving criss-crossed tracks on the part. If the wheel is running too fast, besides wearing a lot of the oil, you will get a dull, galled surface, the same applies if you don't use enough oil. Best to wear vinyl coated work gloves, a long sleeved shirt, and a full face mask, or you will need a shower. But the results are terrific. Not shiny, no tool marks, and fairly resistant to weathering. If you want basic corrfosion resistance, look into commercial "Alodine" solution, a chemical conversion coating that adds nothing to the dimensions of the part, but retards corrosion. Do a Google search for "Alodine" or "chromate conversion" and you will turn up several sources. Auto refinishers use it as a paint prep before painting aluminum. Be sure to follow the instructions closely and use de-ionized water when it says to rinse the part well.

[blackbeard52]

For years we used a drill disk pad available at body shop supply stores and tool suppliers. it has a velcro like hook material on the pad. Simply attach Scotch Brite pad and insert it into a drill press...Cutting the pad round kept it from coming loose often. This did a quick nice job giving whatever finish you needed (depending on grit). Also we used cloth pads soaked in oil and smearing it with valve grinding compound. Gives the swirled effect commonly called jeweling.

Bob

[Rally]

If applicable and or feasible anodizing goes a long way. That is what I do to some of the parts I make. When polished a anodized part will stay shiny much longer. I make bike parts and have found that to be true.

[Martin 007]

Thanks for the info guys. And that is a great looking rotor head your friend has there.

[juliancrouch]

May be a little late for this, but if you have a buffing machine, you can use 3M buffs for a nice satin finish, or of course you could actually buff it to as shiny as you want it. Buffs are fast, easy to clean up, and cheap.