Frit question - WarmGlass.com

Frit question

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Blair
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Frit question

Postby Blair » Wed Apr 17, 2013 10:23 pm

Hi. I started using frit as part of my glass design. For example, when doing a 9 in square platter. I come up with a design. I take a piece of doulble rolled black glass as my base. Then I cut out my design using double rolled iridescent bullseye glass. I leave a space approx 1/8 inch and fill it with med size frit. I also leave a bigger space and fill the space with black glass pebbles and place black frit between the pebbles. I fuse the piece (bringing up to 1300 for 2 min) and then slump it. I do like the look of the frit because it gives texture to the piece.
I gave the piece to my sister. I was in her car with her driving. She took a turn to fast and the box that had the platter in it fell in the back of her suv. We heard it. I told that was not good. It seemed to be ok. But latter in the week she was trying to decide where to display the glass piece. One of the times she picked it up it broke right where the frit and pebble area were. I felt bad that it broke but I want to figure out why it happened. She did say she picked it up on the edge of the platter. I was thinking with using the frit maybe there was too much stress where the frit and pebbles were. (I tried to add a picture of the piece but I am not sure if it will show up).

Maybe I should stay away from frit in larger spaces. What do think? Thank you
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Judd
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Re: Frit question

Postby Judd » Thu Apr 18, 2013 10:08 am

1) I will assume you used all compatible Bullseye glass.
2) You didn't say how long you annealed the piece.
3) Ignoring those other variables, my second question would be why you didn't full fuse? You like the rough, pebble look? If you fired to only 1300, perhaps it was only tack fused and not completely fused - making a structurally weak plate. At least, in my Skutt GM 1414, 1300 would not create a thoroughly fused plate.

Cheryl
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Re: Frit question

Postby Cheryl » Thu Apr 18, 2013 3:48 pm

show us the break. That will help with diagnosis. Also the annealing schedule, as Judd said, is critical. How hot, how long,etc.
"Every artist was first an amateur."

--Ralph Waldo Emerson

Rick Wilton
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Re: Frit question

Postby Rick Wilton » Thu Apr 18, 2013 4:08 pm

"black glass pebbles" ???

What exactly are black glass pebbles? If it's not a tested compatible glass that's the culprit.
Rick Wilton

Blair
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Re: Frit question

Postby Blair » Thu Apr 18, 2013 9:23 pm

All of the glass is Bullseye 90 coe. I made the pebbles first then added them to the design. You are right it was a tack fuse. Here is the schedule I used. 200-950, 400- 1300 hold 2 min., full-950 hold 1 hour.75-700, 150-300. I used the tac fuse to give the platter texture.
After that I did a slumping program. This program was 200-950. 300-1250 hold 27 minutes. Full- 950 hold 1 hour, 75-700, 150-300.
I do not have the platter. It is with my sister in another state. I asked her to keep the platter so I could look at it. It did break where the pebbles are. Thank you for helping me figure out the problem.

Kevin Midgley
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Re: Frit question

Postby Kevin Midgley » Thu Apr 18, 2013 10:01 pm

Not annealed.
Read Stone's firing schedules for glass a few times cover to cover. :-k

Blair
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Re: Frit question

Postby Blair » Sat Apr 20, 2013 9:25 am

Thank you Kevin for your suggestion! I think it is a great idea to purchase the book "Read Stones Firing schedules". It is on my list of to dos today. I have not done a tack fuse like this before. Usually the gaps where I use frit are smaller and I also bring the temperature higher. I did contact Bullseye glass to see what they recommend. I gave them my tack, slumping schedules and a photo of the piece. They based their recommendations on a 6mm total thickness. The thickness of the glass should be considered when deciding the annealing time. Bulleye provides tech notes on Heat and Glass and also a Annealing and thick slab chart.
The individual said the tack fuse used seems adequate. Except they said I could skip the last segment. The person at Bullseye glass also said that adding time to annealing can not hurt a project. And I will add time on the next project that is simalar. I would rather do this than have a problem later. The slump schedule they provided was 300-1225 for 10min., afap-900 for 1 hour, 100-700, afap 70. I am not sure if the hold time will be enough for the slump but I could extend the time and just keep an eye on it.
Thank you for all suggestions! I am looking forward to getting my book in the mail. :)

.

Jeanne
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Location: NJ

Re: Frit question

Postby Jeanne » Sat Apr 20, 2013 11:43 am

Kevin Midgley wrote:Not annealed.
Read Stone's firing schedules for glass a few times cover to cover. :-k


It appears that the piece is 6mm from what I can tell. What's the matter with the annealing schedule?

As to the 1300 top temp firing schedule with a 2 minute hold, I must say that would be very low in my kilns. I wonder how well the piece fused together initially?

Also, I prefer to keep breakables on the floor of my car. You never know when you'll have to stop short.

Morganica
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Re: Frit question

Postby Morganica » Sat Apr 20, 2013 12:10 pm

Probably wasn't well-sintered to begin with, and likely the tack-fuse aspect meant it already had some residual stress. In my experience, lots of little chunks tack fused to bigger tack fused chunks means you've got a lot of areas where not much glass is attached to not much glass.

Those joins tend to contract away from each other during cooling and increase the chance of stress on a join that already can't support the weight of the piece. Doesn't take much to break them. An extra-long anneal cycle can help alleviate that. However, the join will always be a bit fragile, so dropping it or lifting it where the join has to support the rest of the piece, and crrrrack....

Or the other explanation: the initial bump in the car start a crack she couldn't see, and picking it up by that edge finished the job. Or both.
Cynthia Morgan
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Marty
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Re: Frit question

Postby Marty » Sun Apr 21, 2013 9:14 pm

Blair- where'd you get that program?

Blair
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Re: Frit question

Postby Blair » Mon Apr 22, 2013 9:27 pm

Hi. Thanks for your input. I think next time I do a piece that is similar or something new I will do a test firing. I may also may put it on the forum to see what others think. Everyone has been helpful. I did order the book Kevin suggested and I also decided to purchase Bullseyes year video subscription.
Marty which program are you referring to?

Marty
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Re: Frit question

Postby Marty » Tue Apr 23, 2013 6:35 am

Nevermind, Blair- I missed your "contacted BE" post above.

barclayb
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Re: Frit question

Postby barclayb » Mon Apr 21, 2014 9:23 pm

That bowl is gorgeous! Great design.
from the whimsical and peripatetic world of
Barclay Elizabeth Blanchard
(pronounced Barkley)
servant of cats


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