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sansbury
07-13-2010, 01:53 PM
Now that I have reached the point where parts are starting to come off the machines with some predictability, I'm starting to look for ways to put a more presentable finish on them. A lot of my work is of a more artistic/decorative nature so the appearance becomes a significant part.

Most of my work is done in aluminum, brass, or steel in that order, with aluminum accounting for 70-80%.

For the first step I was thinking of a small belt sander and vibratory tumbler like these:

http://www.harborfreight.com/1-inch-x-30-inch-belt-sander-2485.html
http://www.harborfreight.com/5-lb-metal-vibrator-tumbler-93252.html

Most of my parts are relatively small, and my shop is tiny, so I am looking to stick to smaller stuff.

After that, I am thinking about either anodizing or nickel plating as ways to put a final finish on things. I like the opportunity for coloring that anodizing gives, and the super-shiny finish with nickel-plating, but I don't strictly need either one--I just need a way to put a good-looking finish on things that won't rub off too easily. I've looked at the Caswell Plating kits which look really nice, but I've also seen people do with a more homebrew setup and get what seemed like OK results.

Does anyone have any thoughts or suggestions on other things I should be thinking about?

oldbikerdude37
07-13-2010, 02:08 PM
Some Cloth wheels and some jewelers rouge will put the shine to parts.
Some fit a bench grinder and others are small and have an arbor to chuck into a drill press.

Both items are very cheap but do a good job. You may have them already though.

Carld
07-13-2010, 02:57 PM
Tumbling will remove burrs and rough edges but not polish anything. You will need to use a cloth wheel and polishing rouge to get the shine on your parts.

A radius tip and the right speed/feed should get a nice finish on aluminum and brass but steel is another matter.

DeereGuy
07-24-2010, 06:29 PM
Tumbling will remove burrs and rough edges but not polish anything. You will need to use a cloth wheel and polishing rouge to get the shine on your parts.

A radius tip and the right speed/feed should get a nice finish on aluminum and brass but steel is another matter.

Actually depending on the media you are using you can do both in a tumbler. Here is a set of flywheels for one of my little engines that were tumbled in corncob media (I normally use this to polish my 9mm and 45 cal brass).

http://i2.photobucket.com/albums/y39/Deere_X475guy/New%20Shop%20Maching%20and%20Welding/DSC_1515.jpg

The corncob media will not remove machining marks or debur well..but it does make the part shine. Here they are after anodizing.

http://i2.photobucket.com/albums/y39/Deere_X475guy/New%20Shop%20Maching%20and%20Welding/SiameseTwinFlywheels.jpg

firbikrhd1
07-24-2010, 09:28 PM
I have had good results by using a few different techniques. For parts that are very dull I generally begin with wet or dry sandpaper around 600 grit wet with WD 40 or water and polish with a jitterbug or orbital sander on flat surfaces or in the lathe on cylindrical items. These sanders leave marks in a random order, not lineal so they don't draw the eye to a "grain" like finish. However, if a "grain" like finish is what you are looking for rather than a shiny polished finish the belt sander will accomplish that. I use increasingly finer grits up to about 1500 and then a rag with either Flitz, Simichrome or Mother's polish. This method has brought a piece of an aluminum Stop sign recovered from a roadside crash to a mirror like finish after using a propane torch to heat and remove the decal and working through the above steps.

I also use the previously mentioned method of a bench grinder with cloth wheels, jeweler's rouge and the above mentioned polishes after the wet or dry sandpaper treatment. These methods have served me well for every metal I've tried them on. I would be concerned about polishing bearing surfaces using any of these methods, particularly in softer metals. Should some abrasive become embedded in the material it likely would cause premature wear.

One thing I would say is that much time polishing can be saved if very sharp tooling is used to finish the part to it's final dimension. If the tooling is right the tool marks will be barely visible, if at all to the naked eye prior to polishing. High speed steel tooling can be very useful in this area as it can be sharpened to an extremely keen edge. Fine feed, radiused corners that cover more real estate than the feed and higher speeds will be of great help here. Do a search for "shear tool" and you may find some tooling that will provide a very fine finish on the lathe or shaper.

Wire brushes or sanding disks in a drill press can be made to leave overlapping patterns similar to fish scales. I have heard this referred to as a "turned finish" and it is attractive on some projects. Custom dashboards can look "high performance" finished with this method.

None of what I have mentioned cost's much or takes up much room. If you don't have a bench grinder you will find it useful for grinding tooling and many other shop projects. I consider it an essential anyway, more so than a belt sander although both are nice to own.

Weston Bye
07-24-2010, 09:44 PM
I'll second what deere_x475guy suggested. Good work, Bob. I haven't tooled up for tumbling, but do anodizing.

Ken_Shea
07-24-2010, 10:16 PM
Another great finish product is Scotch Brite.

Leaves a nice course or fine brushed type finish depending on the particular Scotch Brite pad used.

bruto
07-25-2010, 01:18 AM
I can't add anything here, but wanted to say I like the thread title.

JoeFin
07-25-2010, 09:12 AM
You'll want to start out with the 3m wheels for "Blending and Deburring". They're great, but they won't be able to reach into the small crevasses and leave a soft "Brush Finish"

After that you'll want to place them in a ceramic vibratory media. Happy Fart sells an 18" Vibratory Bowl finisher for around $160. You'll need 2 of them. Forget about "Professional Vibratory Machines" because they are very expensive and hard to come by

There are companies out there that design and sell engineered ceramic vibratory media, or you can try various combinations or sizes and shapes until you get the desired results. You will also need to run water with the ceramics and change it periodically or rig up a "Drip" system that drains to a 5 gal bucket to flush away the "fines". What you'll get is a uniform dull soft matt finish void of machining marks and ready for the final step if you've done every thing correctly.

Then (and the reason for 2ea vibratory bowls) you'll place the parts in "Dry Green" media in the second vibratory finisher and let it run for 8 hrs or more. This is where all prior steps become very important because rouge covered walnut shells will not remove material.

MuellerNick
07-25-2010, 12:49 PM
Here they are after anodizing.

Bob, that's an interesting color!
Was that brass? How does the process work?


Nick

DeereGuy
07-25-2010, 05:36 PM
Bob, that's an interesting color!
Was that brass? How does the process work?


Nick

Hi Nick,
I don't want to hijack this thread with the process, but I will start a thread on how I am anodizing if you would like to see it. The color is what I am getting from Rit dye "Negro Black". It consistantly comes out this color for me.

MuellerNick
07-25-2010, 05:42 PM
but I will start a thread on how I am anodizing if you would like to see it.

Yes, please! I don't think I'm the only one. :)


Nick

sansbury
07-25-2010, 07:11 PM
Hi Nick,
I don't want to hijack this thread with the process, but I will start a thread on how I am anodizing if you would like to see it.

Please hijack away--anodizing is one of the areas that interest me :)

DeereGuy
07-25-2010, 07:48 PM
[quote=sansbury]Please hijack away--anodizing is one of the areas that interest me :)[/quot
Ok then..since your the OP here we go. Let me first start out by saying most of what I know I can thank our own Weston Bye for. He was kind enough about a year ago to invite me to his home to anodize a protype part I am working on. Next I want to say the chemicals are nasty and dangerous. I am not going to even try to spell out all the hazards...please do a search on the internet and know what they are before you try this yourself. Weston referred me to a link that I have found very helpful so I am including that link here:
http://www.focuser.com/atm/anodize/anodize.html

My setup isn't nearly as nice as his yet....I am working on it. Currently I am using a battery charger that runs from 2 amps to 10 amps and 6 volts to 12 volts. Ideally you would have a constant current power supply to get predictable results but they are big bucks. For the little runs that most of us do in a home shop this way works fine.

I have changed the setup on my anodizing tank several times now and have added a successful way to cool the anodize solution with what I happen to have on hand. I will show that in a later post in this thread.

Have a read through the link that I left and I will be back later in the week with more of what I am doing.

doorknob
08-01-2010, 08:54 PM
Just curious - for when you describe your anodizing setup - can you talk about what kind of surface prep you give the aluminum before putting it into the acid bath? Do you do bead blasting, or etch in sodium hydroxide (and if so, what strength and for how long?), or scuff up the surface with Scotchbrite, or something else?

JoeFin
08-01-2010, 09:11 PM
That is what the thread was about until it turned into anodizing.

I see lots of folks trying to cover up their imperfections with anodizing and the result is a dull fancy looking color. Simply - what you have is what you get with anodizing.

The part really needs to be finished "Bright" before going off to the bath to achieve a really nice anodized finish

Circlip
08-02-2010, 03:22 AM
what you have is what you get

Same with Powder Coating. If you take out or leave dinks in ANY material and try to cover with whatever media you've lost. OK, there's the "layer with filler (Bondo) and rub down and level" brigade but a scratch free original gives a better result. Think Chrome plate too, and just so nobody jumps in, Chrome is a COLOURLESS (Colorless) coating.

Regards Ian.

PS, What's happened to Last nights efforts Bob??

DeereGuy
08-02-2010, 08:37 AM
I am answering this from my phone so it is brief. All....I have switched from a bucket to a ice cooler for the Anodizing tank and am now using a variac with a full wave bridge rectifier for a power supply. I will post pictures and update this thread when I get time...hopefully mid week.

Anodizing will amplify any surface imperfections. The flywheels I posted earlier in the thread were highly finished when they came off the lathe. I then put them in my wife's rock tumbler with corn cob media and tumbled for 24 hours. The were not dipped in the lye solution. ...I just gave them a good scrub down in hot water and regular dawn dishsoap.

Ian....I am still having problems with the scarlette color...another stripping is in order. As an fyi for the rest of you...I am having trouble getting the scarlett Rit dye to take evenly. Perhaps for this color I won't be able to cheap out and will have to order the black and red from caswell.

spope14
08-02-2010, 08:48 AM
i have had great luck with clover compound on a microfiber cloth up to 2000 grit, just be sure if you are going from coarser to finer clover compound grits you are using a new cloth and have cleaned the part completely - prevent grit contamination.

i finish with 3m chrome and metal polish.

i have seen a tumbling media of walnut shells and red rouge that works very well. the salesman took some of my brass turnings and polished them up to what i get them as buffed - though i did do the proper prep of sanding up to 2000 clover compound. had to buy a parts cleaner first though, but the mini tumbler and media would come to just over $1000.00

DeereGuy
08-02-2010, 09:28 AM
Sorry bout the double post.......

DeereGuy
08-02-2010, 06:15 PM
Just curious - for when you describe your anodizing setup - can you talk about what kind of surface prep you give the aluminum before putting it into the acid bath? Do you do bead blasting, or etch in sodium hydroxide (and if so, what strength and for how long?), or scuff up the surface with Scotchbrite, or something else?

Most of the time I do etch in a lye solution. I don't remember the brand name right now but I will post it when I go to the shop.