Bubbles under glass

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Tomcat
Posts: 1
Joined: Fri Mar 19, 2004 12:23 am

Bubbles under glass

Post by Tomcat »

Getting bubbles in my fusing project. I am a new fuser and have successfully completed about 8 projects. The last 3 attempts to fuse have resulted in 1 or 2 golf ball size bubbles under the glass - not between the layers. I have an evenheat kiln with a 12 inch shelf. The piece is an 8 inch circle. I'm using spectrum 96 1/8th thick - one full circle of clear and a second layer of colored strips that cover the whole area of circle. I'm using primo primer and curing at 550F for 25 min. Then I'm using the spectrum schedule for 1/4 glass. I tried 2 full circles of clear and the strips on top of that and got no bubbles but I don't want it that thick. Any suggestions?
Nancy Juhasz
Posts: 113
Joined: Sun Mar 09, 2003 10:10 pm
Location: Ohio

Post by Nancy Juhasz »

My solution to bubbles between the glass and shelf was to use fiber paper. My personal favorite is 110-J since you get a bizillion uses out of it. Yes it seems a little pricey until you use the stuff. Nice texture also. I sprinkle a little kiln wash on the 110-J and smooth it out with a soft brush which I think extends the life of of the paper.

I have heard various theorys about bubbles between the shelf and glass the one I buy into is that the shelf warps during the firing. I used every concievable firing schedule to prevent the bubbles but always seemed to get a small bubble or two until the paper. The interesting thing is I get bubbles if I use kiln wash instead of paper with my Evenheat kiln but not my Skutt. Go figure they both have mulite shelves and both are even in the cold state.

Nanc
Richard Dubois
Posts: 22
Joined: Sun Jun 22, 2003 8:10 pm
Location: SF Bay Area

Post by Richard Dubois »

I also resorted to fiber paper at first, but didn't always want that rough texture you pick up from the paper. So I went back to fusing onto the kiln shelf with kiln wash, but just stretching out the ramp time from 1000-1250F. My standard program now does 75F/hr from 1000 to 1250, then holds there for 30 mins. Bubbles are pretty much gone.

Richard
dee
Posts: 302
Joined: Tue Mar 11, 2003 5:20 pm
Location: Atlanta GA
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Re: Bubbles under glass

Post by dee »

Tomcat wrote:Getting bubbles in my fusing project. I am a new fuser and have successfully completed about 8 projects. The last 3 attempts to fuse have resulted in 1 or 2 golf ball size bubbles under the glass - not between the layers. I have an evenheat kiln with a 12 inch shelf. The piece is an 8 inch circle. I'm using spectrum 96 1/8th thick - one full circle of clear and a second layer of colored strips that cover the whole area of circle. I'm using primo primer and curing at 550F for 25 min. Then I'm using the spectrum schedule for 1/4 glass. I tried 2 full circles of clear and the strips on top of that and got no bubbles but I don't want it that thick. Any suggestions?
i had a very similar problem 2 yrs ago with bullseye glass - i slowed down my ramp times to 300 dph to 1000, hold 10 or 15 min, then 125 or 200 dph to 1250, hold again 10 or 15 min then 125 or 200 dph to my top fusing temp and no longer invite the bubble gremlin to come play with my glass....

D
Dee Janssen
Unicorn's Creations Studio
http://ucjewelry.com
dee@ucjewelry.com
Geri Comstock
Posts: 340
Joined: Mon Mar 10, 2003 4:16 pm
Location: Northern CA
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Post by Geri Comstock »

I solved by bubble problem by buying the kiln shelves made by BE. They are made out of something other than the kiln shelves made by other mfg. Since I started using them, I haven't gotten a single bubble.

Geri
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