[AVRnj]

Hey everyone,

Been CNC'ng for some time now, and never really cared about the finished look of my parts, only that they were sized properly.

I buy most of my ALU online, and it often comes with a bunch of little scratches and nicks and dents.


I have some parts that I want to look more professional than what I usually need.

I am wondering if anyone can give me some ideas on how to go about getting a more professional finish on the ALU after I am done milling it. I know this can range from powder coating to anodizing with or without color.

I am definitely interested in powder coating and/or anodizing, but my main question would be even just getting it ready for that step, as I am sure the nicks, scratches and dents need to be removed prior.

Would sandpaper work, if so, manual or with say an orbital, other?

Any help would be appreciated.

[AARONT]

Ill take a piece of 180 grit sand paper to a piece of round aluminum stock in the lathe, and really load the sand paper up with aluminum. Then "polish" up my parts with that if I find my finish isn't what I desired. Scotch bright pads works also. I would be hesitant to use an orbital on aluminum because you may remove more material than you want to.

[Fiero Addiction]

I just did my first home anodizing job about a month ago. It's really not that difficult, and not too expensive to do small parts. There are plenty of online guides, lots to learn before getting started. If you have some small parts to do occasionally it's worth looking into, but for large production where consistency is required it's probably best left to the pros. For durability it can't be beat. I bead blasted my parts before anodizing to give a matte look, but they can be polished or as machined too.

I've also done lots of powder coating. I have an old kitchen oven in my shop just for that purpose.

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[vertcnc]

vibratory tumbler or concrete type mixer with media for the different operations works well.

[AVRnj]

Guys, thanks for the suggestions. What type of media would work for a concrete mixer?, that sounds pretty interesting.

[vertcnc]

We'll I haven't found any solid information. You best bet is to have good parts to begin with minimal tool marks. I personally have not used the concrete mixer but some of my customers have. It appears that they were using the green abrasive pyramids and a mild soap solution for deburing and cleaning. There are many types of media as you probably already have discovered. Just depends on the final finish your looking for. I have used the pyramids for deburring parts in a vibratory tumbler and works rather well. But you probably would have to follow that up with some ceramic media and for a bright shine something softer with a polishing compound imbedded. I have called a few of the media companies and they weren't very forthcoming with tons of info. You also have to look at the size of the media with the holes and inside corners of the parts and if you wanted these areas to be done also. Best is just to try some different types. Its not a very fast process I've heard of process times for several hours for the abrasive media to 24-48 hours for the polishing medias.

[AVRnj]

vertcnc, thanks much! this is very helpful. I get the idea and I think I will experiment with it a bit. Much appreciated.

[Iron-Man]

You can see my post'http://www.cnczone.com/forums/bencht...d-candy-4.html

I used Candy Red Translucent; powder coating.


Hope this helps,

Iron-Man

[AVRnj]

Iron-Man, thanks. I have looked into both powder coating and also anodizing, and I am very interested in both.

However, I think I probably titled this thread incorrectly, my problem is more in prepping the aluminum for the finishing than actually finishing. After milling I have all kinds of lines that show from various passes and the tool path markings, along with a bunch of scratches and scuffs on the aluminum there were there before I even started milling it.

I am pretty sure that either anodizing or powder coating will still show all the lines, scratches and scuffs, so I think before I even get that far, I need to be able to clean up and prep the piece. The tumbling in a media is interesting, and I am interested to hear any other methods for prepping before powder coating or anodizing.

Thanks.

[Fiero Addiction]

If you're just doing a few parts here and there, blasting is the way to go. You can vary the pressure and media to suit the job, and give more attention to areas that need it. Tumbling is slow and noisy, but would be more efficient if you're doing large batches of parts. Powder coating can hide a lot of imperfections, but it can also hide fine details and affect assembly clearances. Anodizing doesn't hide anything.