Color fill engraved text on painted aluminum?

[Randy Digby]

Here is the task. Engrave text (.30 high and less) on an aluminum clipboard that has, what appears to be, a light grey powder coat paint finish. Does anyone have a process they would share to color fill the text and remove the excess paint from aroung the text without washing out the colorfill. Ideal color for text would be black or red, so rub-n-buff stuff is out (I've only seen it in silver & gold). I can get close with acrylic paint, but not consistent enough for a production part which needs a repeatable process. Curently I'm using a Batang font, rastering only the text outline, which is set at .015 inches wide. I would prefer not to use Thermark because of cost and layout time required. I use Thermark on a large anodized aluminum boad with veryy acceptable and repeatable results, but the larger board has enough profit in it to cover the Thermark cost a prep time. I have my best paint retention results at 100 25 500dpi, but still not good enough - after I finish cleaning the board.

[Garrett Nors]

Sounds very difficult. Do you have a vinyl cutter or could you possibly use a rowmark product to sub as a vinyl letter?

[Randy Digby]

I currently produce the product using vinyl lettering. I was wanting to develop a lasered alternative for product durability.

[Chris J Drew]

Would rastering through a low/medium-tack film mask, spraying the fill & then peeling off the mask add too much time to this?

[Mike Null]

I use acrylic paint then clean with a card before it's
dry then later with alcohol on a rag wrapped around a card.

Laser through the powder coat to the metal. That usually takes me two passes to get a clean engraving mark.

[Randy Digby]

Chris -
That's a thought. All I have is light tack masking tape for vinyl transfer. Could you point me toward a source for film material?

Mike -
I'm using bottled acrylic from the craft store and applying with a small foam brush. Is that you paint application method? What type card? - Like business card stock or something different? Haven't tried alcohol, just water on a rag which requires a good bit of force to clean the surrounding surface.

Thanks guys.

[Dan Hintz]

If you need something in a rush, I use blue painter's tape and rub the surface well to make sure there are no bubbles. Laser through, then give it a light coat of paint... keep it light and hold it far enough away so the paint is almost dry by the time it hits the board, which prevents it from wicking underneath any bubbles you missed. I spray deep-etched marble tiles this way and the text (often a tight-lined cursive or flowery script) always comes out well-defined.

If you have time to order, pick up a medium tack vinyl mask tape. Powder-coated surfaces are usually quite smooth, so you shouldn't have many problems with wicking.

[Scott Shepherd]

There is a laserable sandblast mask that's supposed to hold very fine detail. I'd bet that would work very well. Laser away what you want filled and then fill it, remove the mask. Should give sharp lines.

[Randy Digby]

OK. Good info from the Creek, as always. For the paint application, what dpi would you suggest? I have been doing everything at 500.

[Mike Null]

I use craft store acrylic and clean it with something like a business card. for the final cleaning I wrap a rag around some scrap plastic and put some alcohol on it. I usually don't have a problem if the finish is a powder coat.

[russell dietrich]

There is a product in the Plastic Plus catalog that says it will turn engraved letters on aluminum black. I have never tried it.

[Mike Null]

That product will not work with lasered items. First, in order for it to work the surface must be lacquer coated; then you mechanically engrave the image through the lacquer and oxidize the engraved image.

The laser does not burn away the lacquer sufficiently to give and even oxidized result.

[Brian Robison]

Or, to add to what Mike wrote, laser through a sandblast mask and blast it, then you can oxidize.

[Randy Digby]

Progress status:

I had some good test going and the fax machine came alive with several large orders (YEA!!) so testing will have to continue in a few days. What I was ale to do was burn thru the paint and oxidize the aluminum with solution. With only 30 watts, it took a little time and a couple of passes, but the preliminary results look promising. The best solution would be one that allows me to use different colors, but like Henery Ford said...black will work just fine.

I had oxidizing solution on hand from when we drag engraved our anodized aluminum pieces prior to the laser and had not thought about using it untill you guys brought it up. As much as I try to tear down boxes, I can be caught building them around me some days!

Oh yea...no sandblaster yet...maybe some day.

Thanks for your help, and if I reach an acceptable and repeatable soultion, I follow the tradition of the Creek and post a picture.

Back to work....

[Ed Peters]

sold by "Beckley" which is formulated for this purpose. The engraving is filled with a small squeeze bottle with a needle tip. We then wipe off the excess with a double sheet of tp (yes, toilet paper) wrapped onto a flat block and dempened in toluol or acetone. Normally a single wipe is all that is required for a clean image.

Ed

[Randy Digby]

Ed,
Guess I'm Google stumped tonight...can yoiu send me a link to a supply point for the paint?
Thanks so much.