Engraving anodized aluminum - color fill?

[Neil_J]

Hi,

Now that my CNC is successfully engraving aluminum and PCB's, I'm looking for a way to color-fill the bare aluminum as shown here:

Anodized/color-filled panels

For clear anodizing, I've found that you can oxidize the aluminum which turns the bare metal black (of course the anodizing is unaffected), which sort of looks like the first picture in the link. Johnson Plastics sells the oxidizing compound for aluminum and brass.

My question is, does anyone know what type of process is best for other colors of fill, such as white? Paint sticks, etc????

[eman5oh]

You could use a liquid mask before engraving and them spray paint the lettering and then remove the mask.

[sdjdave]

The best way to fill in lettering is to use color fill enamel, which is actually a two part epoxy. Whenever you see small color accents added to something (like the red and blue on the shield of a United Airlines employee's wings), it was probably done with color fill. It's a two part mixture, like any other epoxy, and requires 24 hours to cure. It's fairly thin, and is usually applied using a hypodermic syringe attached to a valving system that uses a foot pedal to trigger the compressed air that drives the plunger in the syringe. The valving system allows you to adjust the amount of time the valve is open so you can apply just a tiny amount, or you can flood an area with the epoxy. The system usually runs about $1000, but with a little thought and a Basic Stamp or Microchip PIC, you can build your own. Do an internet search for color fill and you should find some useful links.

Dave

[Neil_J]

Originally Posted by sdjdave It's fairly thin, and is usually applied using a hypodermic syringe attached to a valving system that uses a foot pedal to trigger the compressed air that drives the plunger in the syringe.

So would you be applying it just to the engraved part, or just smear it across the whole plate? And if so, what would it be cleaned up with? It would seem very time consuming if each letter had to be done seperatly...


Thanks,

Neil

[rc-cellar]

I'm also toying with metal engraving... found these anodized business cards (2"x3.5") on ebay... very nice results.

Does anyone know of an online source for larger black anodized sheets ???
would prefer not to hassle with taking them to a plater.

Neil, can you tell us more about this oxidizer?

I assume it would make black letters w/bare metal background ?
What is the process? smear-on, wipe-off?
Is the quality good? edges are sharp?

Do you have any photos?

[Neil_J]

Originally Posted by rc-cellar I'm also toying with metal engraving... found these anodized business cards (2"x3.5") on ebay... very nice results.

Nice, I'll be doing those with both anodized aluminum pieces, and printed circuit boards, which I am also doing on my mill (both with great results so far)

Does anyone know of an online source for larger black anodized sheets ??? would prefer not to hassle with taking them to a plater.

I bought the anodizing kit from Ron Newman's site for $114, which comes in a bunch of colors...

can you tell us more about this oxidizer? I assume it would make black letters w/bare metal background ? What is the process? smear-on, wipe-off? Is the quality good? edges are sharp?

It would be used for black text on an anodized plate of aluminum (either dyed any color, or clear[silver]). Process is applying with a q-tip, waiting, and wiping off, possibly rinsing with soap and water. It is OK to apply it to the anodized material, it is not affected by the oxidizer. Quality is as good as your engraved edges (i.e. 10k+RPM=good clean edges, <10k RPM=burrs and rough edges), and should be good enough to read letters of .003" wide cuts...
I bought this solution from Johnson Plastics a few days ago, I will reply here and let you know my results.

Do you have any photos?

Here are a few I took at work today, unfortunately none are color-filled yet. This is a piece of aircraft test equipment we are redesigning that is used to verify fuel monitoring systems within the airplane

[Neil_J]

more pics

[rc-cellar]

Home anodizing... not gonna go there, I'm in too deep already.

JohnsonPlastics had exactly what I wanted - 1/16" black ano-sheet 12x24
Thanks for the link!

Gotta try that oxidizer too, but I'll let you go first.

[widgitmaster]

Hello Neil,

A few years ago I had a project in our shop which required color filling of the engavings done in house, the customer was not too fussy, and we experimented with various automotive acrylic paints. We simply put some on with a syringe, then spread it across the plate with a red piece of rubber, the kind they used to put bondo & filler on auto fenders! When dry, we wiped the plates with Acetone to remove the haze. End product was very impressive for the low cost!

Eric

[mgamber]

Here are a few I took at work today, unfortunately none are color-filled yet. This is a piece of aircraft test equipment we are redesigning that is used to verify fuel monitoring systems within the airplane

What kind of bit did you use? Depth? Feeds and Speeds?

[sdjdave]

Acetone will take care of your clean up. You could probably do the flood routine, although using the applicator with a syringe allows you to use really small needles so you can do letters really easily. The foot pedal and all the adjustments makes it easy to put just the right amount of material in each letter without overflowing and an experienced operator can fill quite a few letters pretty quickly. My wife used to work for the company that did United Airlines and America West Airlines wings and she could do a tray of 50 wings that had some small specks of color in about 2 to 3 minutes. If she had lettering to do, she would put in the first small squirt, use the needle to run it all over the letter to wet it, then give enough squirts to bring the level up where it belonged. She rarely overfilled, and didn't have to do any clean up. This was all done on highly polished plated surfaces, so any screw ups were really obvious. Since most of the fonts used for panel engraving are simple sans serif types, they aren't that hard to do. The real beauty of the color fill stuff is that it self levels and because of the 24 hour cure time, the letters come out nice and glossy, plus they aren't affected by alcohol or any other common cleaning solutions, so they last a long time. With practice you can get fast doing the filling, but use whatever method works best for you. I just feel that trying to do the clean up after doing the flood type fill may ruin your nice glossy letters.

Dave

[mgamber]

Not using any fill... Will that be a problem in the future with corrosion?