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Tack fusing onto an irid surface

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Tack fusing onto an irid surface

Postby Annette Paajanen » Wed Feb 17, 2010 7:23 pm

One of the things I am trying to do is tack fuse onto irid surfaces, and I have experienced inconsistent results. I like to make smaller "bubbles" prefused generally with clear but sometimes with colors in various sizes, from 3/4 to 1-1/4 inch in diameter. Sometimes, after going through the tack fuse schedule, the bubbles just pop off, leaving an indentation, while other times they stick. For this latest piece, I used a conservative schedule (maybe too conservative for what I'm doing, but this schedule suggested by Susan Green -- thanks! --saved the day on another piece, and I like to stick to what works), going up at 50/hr until 1000 degrees and then 100/hr to 1300, holding for 10 minutes. However, on a previous piece, I took it up to 1325 and held for 15, also with inconsistent results. Is there something about the irid surface that makes tack fusing more difficult? Is there a way to make the non-irid glass bits stick to the irid, yet keep the texture I want? I would hate to have to resort to glue, as my husband suggested! Thanks for any help?
Annette Paajanen
Annette Paajanen
 
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Joined: Tue Jan 26, 2010 8:59 am
Location: Las Cruces, NM

Re: Tack fusing onto an irid surface

Postby Jerry Jensen » Wed Feb 17, 2010 9:30 pm

Irid is a metalic coating that resists fusing, most of the time you need to leave exposed glass with no coating to insure a proper fuse. There are ways of breaking the surface that may work like streaching the irid so that it fractures and leaves areas of non iridized glass that can be fused to or if you are casing in a large area leave a bit on non iridized glass around the edge for the casing glass to stick to. This is especially true in tack fusing. If I understand your application you may have to etch, sandblast a grid, or abrade the surface enough to get the frit to tack to the non iridized surfaces. Good luck!
Jerry Jensen
 

Re: Tack fusing onto an irid surface

Postby Annette Paajanen » Thu Feb 18, 2010 6:57 am

Thanks, Jerry. I will try the abrading idea, since I don't have a sandblaster. I knew that irid is metallic but, since I successfully fuse irid to irid (though with a plain glass edge for the top irid to stick to), that plain glass would stick to irid. Guess not.
Annette Paajanen
Annette Paajanen
 
Posts: 4
Joined: Tue Jan 26, 2010 8:59 am
Location: Las Cruces, NM

Re: Tack fusing onto an irid surface

Postby Jerry Jensen » Sun Feb 21, 2010 12:45 pm

It is my understanding that metallic surfaces like irid and dicro technically do not fuse but can just be cased in with other glass that fuses together at lease in some way. I have seen that particularly on fusing coatings of Micas, the edges tend to show powders even after fusing. I could be wrong but I have always approached coatings with this in mind but not rigorously tested coatings personally.
Jerry Jensen
 

Re: Tack fusing onto an irid surface

Postby kgkennedy » Tue Mar 02, 2010 1:01 pm

Hi. I fuse irid to irid quite a lot.
First make sure that you are not putting the coated sides together. Coated surfaces will not stick, and generally pop off just as you describe, under heat. This also applies to dichroic coatings. If your irid is facing up then the surface that lays down on it must be uncoated glass. If you want to, you can try putting a layer of super shine between the two coated surfaces as they touch, and then fire them out. But supershine tends to supress the appearance of the irid coating. I suspect that you are trying to get a lens effect over the irid while doubling the luster effect. You could add a double rolled layer of (clear) glass, either sandwiched between the two surfaces of the irid, or stack on top as I first suggested, to get a lens effect. It would stand up pretty tall on a tack fuse.
Also vent your kiln during the first 150 to 200 degrees of heating, then close and run at the same temp setting for about half an hour, your luster will be smoother. I don't know what thickness of glass you are using, your firing schedule seems slow. I was told that you can run at about 300 degrees an hour, but I fire closer to 225/hour.
kgkennedy
 


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