Instructables
Picture of Adding color to laser etched acrylic at Techshop
I wanted to color the labels on an acrylic box for a Raspberry Pi enclosure with a paint.  This method uses a powder which is etched into the laser engraving. The powder used is called LaserDarc. I bought a sample of 3 colors for around $70.  

The Raspberry Pi enclosure pattern was from Thingiverse.

The laser used was the Trotec Speedy 300 at my local Techshop. This instructable assumes you already know how to cut and etch acrylic on your laser. 
 
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Step 1: Etching the acrylic plastic

Picture of Etching the acrylic plastic
The first step is to etch the acrylic. I used the default setting for etching but ran the job 3 times to get enough depth to hold the paint.

Step 2: Loading the paint powder

Picture of Loading the paint powder
This is the messy part.  Remove acrylic from laser. Over some cardboard, or preferably in a cake pan, fill the etching with the colored powder.  Try to brush some into every nook and cranny.  

Step 3: Brush off the excess powder

Picture of Brush off the excess powder
Using a straight edge ( I used a credit card) brush off the excess powder.  The excess powder can be placed back into container.

Step 4: Re-engrave your image

Picture of Re-engrave your image
Place the acrylic back into the laser.  Run the engraver at low power and high speed.  I followed the directions included with the powder at 20% power and 80% speed.

Step 5: Repeat as necessary

Picture of Repeat as necessary
If you engraved your acrylic deep enough and got enough powder into the etching you are almost there. If not just repeat applying the powder and etching until you are satisfied with the results.  Some trial and error will be involved.

Step 6: Cut the acrylic

Picture of Cut the acrylic
After you are satisfied with paint process you can cut your pieces out.  This was done last so that the etching would be over the exact same spot as the process of remove, paint and etch is repeated.  These pieces here still need a little cleaning.
kde leon31 year ago
what paint powder is it? thanks! :)
theshades1 year ago
ERR Power that melts at high temp. UMM? toner power?
POWDER
Awesome! I bought some LaserDarc a while back, but have only used it on wood. Can't wait to try acrylic.
Easier method- get some masking paper, stick it on, etch the part, and spray paint. Works like a charm :)
ccrome1 year ago
Huh, wikipedia says this about powder coating:

Curing
When a thermoset powder is exposed to elevated temperature, it begins to melt, flows out, and then chemically reacts to form a higher molecular weight polymer in a network-like structure. This cure process, called crosslinking, requires a certain temperature for a certain length of time in order to reach full cure and establish the full film properties for which the material was designed. Normally the powders cure at 200°C (390°F) for 10 minutes. The curing schedule could vary according to the manufacturer's specifications. The application of energy to the product to be cured can be accomplished by convection cure ovens infrared cure ovens, or by laser curing process. The latter demonstrates significant reduction of curing time.


So, regular powder coating may work just fine! Might require a little experimentation, but I bet it'll work.
ccrome1 year ago
Will this work with powder coating powder? Worth a try I think. Cheap and lots of colors.
noahw1 year ago
I didn't know that they had laserable pigments and paints. Thanks for the heads up on this.

I've also gotten great results with painting an entire surface that doesn't react to a low power beam, like aluminum or steel sheet, then, using the laser to burn off and etch away either the positive or negative of my painted image/text to get the same effect. Also, at Instructables we have made many signs using the wipe on wipe off method that rickharris also mentions in their comment. It requires just a little bit of touch-up and care, but is fast and cheap and definitely works well in anything that has the little well etched in it to contain and protect the paint during the wipe off. Thanks for the project - it's always great to learn a new technique!
rickharris1 year ago
Etching your logo/words and then wipe over with a cloth with a little acrylic paint on it - Works as well.