Distressed look for Iridized glass - WarmGlass.com

Distressed look for Iridized glass

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Bob W
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Joined: Sat Sep 27, 2014 5:34 pm

Distressed look for Iridized glass

Postby Bob W » Sat Sep 27, 2014 8:12 pm

Hi folks.....

I am interested in making an iridized plate with a distressed "organic" look . The effect I am looking for are cracks in the Iridized layer and a matt finish. I know it can be done as I have seen the effect on a few plates that are on the internet. For example.... http://www.pinterest.com/pin/405535141417585192/

I have been using COE96 iridized glass to date with no success . No matter what I try face up, face down, face up then down... I cannot get cracks in my Iridized layer. My most recent attempt was Iridized fired face up on two layers of black making 3 layers in total. The plan was to use the spreading glass to pull the iridized layer apart and create cracks, but it stubbornly refuses to crack, so I am left with perfect rectangles of smooth shiny iridized metal surrounded by black.

Has anyone got any ideas of how to generate cracks in the iridized layer ?


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Location: S.E. Queensland Australia

Re: Distressed look for Iridized glass

Postby Buttercup » Sat Sep 27, 2014 8:48 pm

Would those be compression cracks as the inside of the bowl compensates for the slump? Dunno, just wondering? Jen

Bob W
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Joined: Sat Sep 27, 2014 5:34 pm

Re: Distressed look for Iridized glass

Postby Bob W » Sat Sep 27, 2014 8:56 pm

Hi Buttercup ......
Cracks are usually generated in tension ...... the matt finish is created as the surface is pressed together and the Irid layer undergoes some micro rippling......
I think this is the product of multiple firing, the first face up to put the surface in tension (and generate then open cracks) then to slump or put face down and put the surface into compression and get the matt surface, but I am still not able to replicate the surface....

Thanks for the thoughts


Bob W

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Joined: Mon Mar 10, 2003 3:08 pm

Re: Distressed look for Iridized glass

Postby charlie » Sat Sep 27, 2014 9:56 pm

cracks in irid are caused by the glass underneath it stretching. the metal layer doesn't, so when the glass under it moves, the cracks appear.

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Location: Wyoming, USA

Re: Distressed look for Iridized glass

Postby Jeanice » Sun Sep 28, 2014 11:09 am

I'm not experienced enough with irids to provide an accurate response but one thing comes to mind. Could you encourage cracks in the irid coating by lightly scratching it? The scratch would make the coating weaker in that location so that it might actually open once the glass itself starts moving in the heat.

Scratch with... a sharp scrap of glass, razor blade, glass cutter. Or maybe go so far as to use a dremel with a diamond bit. When making the scratches I would use your non-dominant hand to make the scratches more random and less straight.

I could be WAY off with this.

Valerie Adams
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Location: Santa Rosa, California

Re: Distressed look for Iridized glass

Postby Valerie Adams » Sun Sep 28, 2014 1:30 pm

I have very little experience with Spectrum irids but when I tried them, I didn't find the irid coating to be as intense as Bullseye's, so that could be part of the situation.

But to get irid to crack like that, I've fired it hotter than I normally do, and then do sacrifice cuts to clean up the edges.

Bob W
Posts: 4
Joined: Sat Sep 27, 2014 5:34 pm

Re: Distressed look for Iridized glass

Postby Bob W » Sun Sep 28, 2014 7:17 pm

I have attached a photo of one of my test pieces. This was made with three layers to encourage the glass to flow beneath the irid and pull it apart. I got 5mm movement but as you can see no cracks in the Irid. I liked Valerie's suggestion of firing hot, and Jeanice's thoughts on scratching. I will work them into a test piece next weekend.

Thanks to all for your thoughts and feedback

Bob W
no crack irid.jpg
Test Piece

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