Dichroic glass settings?

[Jack Harper]

Hello - Does anyone have any laser settings and or procedures for lasering away the coating on dichroic glass without etching the glass? Thanks.

[Dan Hintz]

Jack,

I'm not sure if it's possible. Since the metallization is made by vapor deposition, it's embedded in the glass (if only superficially)... by the time you have enough power to remove the metallization, you're already etching the glass. You may find a sweet spot for power, but I tend to doubt it.

[Jack Harper]

Dan - Apparently this is done now, but I cannot find out how. If I were to guess, I would guess a YAG over CO2, but I really don't know.

[nancy barry]

I used to laser dichroic glass quite often.. Settings depended on the thickness of the glass and the size of the piece. The dichroic , especially the thinner stuff,seems to absorb heat and break a lot more easily than plain glass. I agree with Angus that the laser etches the glass beneath the coating. It can be made "clear" again by heating to fusing temps of ~1400 * +.

Do you have an image of what you want to do?

nancyB

[Dan Hintz]

Hmmm, a YAG would seem more appropriate in this case (I was thinking strictly CO2, that whole "If all you have is a hammer" thing). The metal would absorb the YAG wavelength, but the glass would pass it... as long as the metal layer isn't too thick and captures/passes the heat along to the glass, that may be the way to go. Nancy's suggestion of reheating is a way to go (this is obviously done outside of the laser), but requires a second step.

[Jack Harper]

Thanks again for the input.

Nancy - I want to do just small simple patterns that will be set in side melted glass. This is just a hobby project and as such, not worth the investment in a YAG. I will give your heating suggestion a try. Thanks.

[Bill Cunningham]

A search produced this thread
http://www.sawmillcreek.org/showthread.php?t=53672&highlight=dichroic+glass