CO2 Laser absorbing paint???

[ifeliciano]

I was watching a video on YT where they are engraving an acrylic panel that is painted in white, then top coated in black. Then they proceed to laser engrave the acrylic and only burn off the black paint, claiming the white is "laser color".
Is there such a thing as a CO2 laser absorbing paint?




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[brian257]

I think most paints will absorb laser, hence be burned away. I used a blue engine enamel from a spray can once as a solder resist and removed with my laser. The harder part will be finding the white paint that reflects the laser. Just because it is white does not necessarily mean that it will also reflect an IR laser. Different wavelengths of laser will require different paints. I am sure you can buy paints that are made to be reflective to a laser, but you might just experiment with different spray cans.

I do my engraving on reverse engrave acrylic withe paint fill. Basically it is a clear piece of acrylic with a thin backing of black, white, or other color plastic. You engrave from the back colored side deep enough to go through the color, but not all the way through the material then fill it with paint. From the front side you have a durable and perfectly smooth surface and you can do multicolor by engraving, painting with one color, engraving other areas, then filling with another color. Works great and is available from Rowmark and other engraving plastic suppliers.

[Blackened]

It looks to me like the white layer wouldn't need to be super reflective, just able to withstand a bit more power relative to the black layer? Maybe it's a paint mixed with a metal powder like aluminium or another good conductor of heat.

[brian257]

Blackened, I don't think it is withstanding the laser is what is needed. If it is a material that absorbs the wavelength of the laser it will vaporize, burn, or at least get very hot. What is needed is something that will reflect, not absorb the laser.

[Blackened]

Blackened, I don't think it is withstanding the laser is what is needed. If it is a material that absorbs the wavelength of the laser it will vaporize, burn, or at least get very hot. What is needed is something that will reflect, not absorb the laser.

Sorry, I wasn't very clear was I lol. I agree that the white layer would need to be reflective to the laser. If you have a close look at the video, it appears to me that it takes 3 passes to remove all the black coating. Therefore, IMHO the white coating doesn't need to be particularly resistant to the beam, just reflect or dissipate enough energy to survive what little beam energy it's exposed to. It's not a polished mirror surface, so it will absorb a proportion of the beam. Probably more important that it doesn't discolour.

[ifeliciano]

Thanks for the observations. So I did use the wrong term by saying "absorbing", when in reality I meant reflective or that it's impervious to the laser beam.