Removing Dichroic coating without damaging glass

[Randy Walker]

Has anyone tried to remove the dicroic coating from glass without damaging the glass?
I am trying to layout ideas for my laser.
I would try it myself except I don't actualy have my laser yet.
Dicroich is the shimmery metalic coating on art glass.

[Darryl Hazen]

Randy,

I don't think that's possible. The dichroic coating is a plasma coating process. The only way I know to remove it is by sandblasting or surface etching.

From Wikipedia:
Multiple ultra-thin layers of different metal oxides (gold (http://www.sawmillcreek.org/wiki/Gold), silver (http://www.sawmillcreek.org/wiki/Silver), titanium (http://www.sawmillcreek.org/wiki/Titanium), chromium (http://www.sawmillcreek.org/wiki/Chromium), aluminium (http://www.sawmillcreek.org/wiki/Aluminium), zirconium (http://www.sawmillcreek.org/wiki/Zirconium), magnesium (http://www.sawmillcreek.org/wiki/Magnesium), silicon (http://www.sawmillcreek.org/wiki/Silicon)) are vaporised by an electron beam in a vacuum chamber. The vapour then condenses on the surface of the glass in the form of a crystal structure. This is sometimes followed by a protective layer of quartz (http://www.sawmillcreek.org/wiki/Quartz) crystal.[2] (http://www.sawmillcreek.org/#cite_note-cbs-1) The finished glass can have as many as 30[2] (http://www.sawmillcreek.org/#cite_note-cbs-1) to 50 layers of these materials yet the thickness of the total coating is approximately 30[2] (http://www.sawmillcreek.org/#cite_note-cbs-1) to 35 millionths of an inch (about 760 to 890 nm). The coating that is created is very similar to a gemstone (http://www.sawmillcreek.org/wiki/Gemstone) and, by careful control of thickness, different colours are obtained.

[Michael Hunter]

Laser engraving dichroic glass removes the "shimmer" but does engrave the glass as well - leaving the typical frosted surface.
Subsequent heating or slumping of the glass removes most of the frosting to give a textured gloss effect.

To retain a smooth high gloss on the glass surface, mirror engrave the dichroic and then fuse it dichroic-face-down onto another sheet of glass. This is very attractive as the dichroic "shimmer" appears to float under the glass surface. Great for jewelry!

The dichroic stuff is so firmly attached to the glass surface that the only other way to remove it would be chemical etching.

[Randy Walker]

Thank you so much Darryl and Michael. I have also found some post in the archive that said much the same thing and that the dichroic may have even damaged the lenses of someones laser.http://www.sawmillcreek.org/images/icons/icon7.gif

[nancy barry]

Several wholesale companies in the stained glass realm now own lasers and offer laser- etched images made for fusing. I have done quite a bit of dichro etching with my laser and have not found it to be a problem. Etched piece of glass needs to be fused in order for the area where the coating was removed to look shiny again. This also seals the dichro coating so that it is permanent.
nancyB

[Randy Walker]

Thank you Nancy. Dichro etching is one of the things that I realy want to get into. You all have been a great help In my product planning.

[Jack Harper]

Several wholesale companies in the stained glass realm now own lasers and offer laser- etched images made for fusing. I have done quite a bit of dichro etching with my laser and have not found it to be a problem. Etched piece of glass needs to be fused in order for the area where the coating was removed to look shiny again. This also seals the dichro coating so that it is permanent.
nancyB

Nancy- I would love to see some pics of what you are talking about.

[Michael Hunter]

Here is a picture of a cuff-link. In case you can't make it out (OK - it's a BAD picture), it is a 2-masted open sailing boat.

I engraved the yellow/gold/blue clear dichroic glass. My glassworker friend then cut it up and fused the images face-down onto opaque deep-blue glass (and fixed on the cuff-link bits with glue, but that's on the back where you can't see it).

I have to say that the real thing is much more attractive than my snap!

[Jack Harper]

Michael - Very nice work. I cut this glass on my waterjet but have never tried to laser it. I will have to play around and see what happens. Thanks.

[Randy Walker]

Wow Michael
Thats great. I hope my stuff looks that good. I can't wait for my laser to get here.. Thanks for the new idea too. My wife has never done mens jewelery. We will have to do some investigation into that market to find out where we can wholesale mens finery.http://www.sawmillcreek.org/images/icons/icon14.gif

Randy