Materials or products that burn into colors

[Josh Jackson]

Hello my Sawmill Family. I have looked through the past conversations and without going down rabbit holes to find an answer I figured I'd just ask. Has anyone found materials, products, or chemicals that when engraved go into a color effect? By colors I mean other than the tan, black or frosted colors. I am meaning aside from the Cermark/Thermark lines. This is more of a curiousity at the moment. I am still 6 months in and have a substantial learning curve, but worth asking. And it doesn't matter what the base product is just any combination of product with 'add on' that makes colors. Thanks.

[Bruce Boone]

Titanium and stainless can both be colored by heat, but it is very difficult (for me at least) to get repeatable results. LaserStar does some samples like that where they do American Flags with the proper colors just by playing with the heat.

[Joe Hillmann]

Most plastics turn colors and leave a raised embossed look when hit with a yag laser. Although if you wanted multicolor engraving it may take a lot of fine tuning to make it work.

I think Cermark makes colored sprays for glass, I have never tried them though.

Also as Bruce said titanium and stainless both have a whole range of color depending on how you heat them.

If you want color you can always do color filling.

[Josh Jackson]

Well I don't have the YAG yet. It's on the shopping list. I've been doing color fill, but still having mixed results. Like I said, this was an entertaining thought. I have a 35w CO2 laser. Ironically I was cutting some plastic business cards and it somehow cut into my metal table. Not a clue how but it's definitely cut in.

[Dave Sheldrake]

somehow cut into my metal table.

Not as unusual as it seems,the power density of short focal lengths applied to even low power lasers can mark / cut metal given enough time to do so. Metal cutting is an index between reflectivity (absorption rate) time and power. In most cases it's not practical (cycle times in weeks or months) but possible and practical are often two very different things.

best wishes

Dave

[Finn Espen Gundersen]

Lasering microfiber cloth such as swimming towels results in an evenly colored mark slightly darker than the original. I guess it is not what you are after, but at least the mark isn't burnt or frosted, it really has a beautiful color.

[Mike Lysov]

There was a thread on SMG where people were suggesting using powder paint for powder coating to do colorful engraving. Logically it seemed it should work as you need heat to melt this type of powder. However I have tried it and I do not think that's a good idea, at least I could not get nice leveled colour.
But may be I have been using wrong powder or wrong power/speed settings.

[Dave Sheldrake]

Hiya Mike,


Logically it seemed it should work as you need heat to melt this type of powder.

Remember laser beams have no temperature as such, they do not have a heat value, simplistically because they are photons not atoms and temperature is an average of vibrational energy between atoms.

If you can find a powder that absorbs radiation at a given wavelength then powder coating with a laser should be possible, that said it's likely the absorption rates of different colours (different atomic structures) would be different hence getting reliable results with narrow wavelengths would be a lot more difficult than it may appear.

Lower power UV lasers may well work in a similar fashion to the Form1 3D laser sintering printer if the beam is used to "weld" the bonding resin rather than the actual chemical colours, would likely also only need mW of power rather than watts or kilowatts.....

best wishes

Dave

[Mike Lysov]

Hiya Mike,



Remember laser beams have no temperature as such, they do not have a heat value, simplistically because they are photons not atoms and temperature is an average of vibrational energy between atoms.


Dave

Hi Dave,

I did not mean heat inside a laser beam. Sure it should not have any high temperature. However heat is generated when the beam hits material surface. So since the beam fired into powder it should melt it. It just does not do it evenly everywhere and it does not allow paint to self level.

[Dee Gallo]

I got some colors to appear on white coil stock by using different speed/power settings. Try some!

[Mike S White]

I have no Idea if it actually Works But I found this page. http://www.smoke-wood.com/SM-wd-21.HTML
To me it looks like some kind of powder coat as mentioned above.