Nutty,Dave pics .... high-fires, pot melts, etc

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Nutty,Dave
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Nutty,Dave pics .... high-fires, pot melts, etc

Post by Nutty,Dave »

I did another high fire experiment but this one partially failed ... i forgot my shelf dams so the glass flowed ... off the shelf ... and the circuit breaker tripped so the kiln cooled too fast ... CRACK!

but i will salvage most of it into other pieces.


http://www.ibnutty.com/hi-fire_2.html
Last edited by Nutty,Dave on Mon Mar 08, 2004 3:42 am, edited 2 times in total.
Peace Through Art !!!
cindyj

Cracked one of my high fire experiments too

Post by cindyj »

I also have joined the hi-fire craze. My first experiment ended up cracked. Didn't cool correctly-the colors were okay though. Second experiment went smoothly with lots of SLOW cooling time. Not as happy with the color combo's. Now I need to figure out what I could cut this slab with to use in other projects.

Love seeing your pictures. Keep 'coming

Cindy
Nutty,Dave
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some more hi-fires

Post by Nutty,Dave »

Here is a picture of some high fire pieces i did ... they were all done in a 2.5" clay saucer (except for the 4" one) with kiln wash ... some of the wash & clay stuck a little but i ground it off ... besides - they are tacked into clean clay saucers with a dab of hot glue.

They are all BE glass ... the 4" one and the lime green one were BE rods i use in torchwork ... the rods were snipped into pieces, fused into discs at 1475 (in a clay saucer), then 2 discs were stacked in the saucers for the hi-fire ... the orange/black one was BE pieces that had been cut into small triangles ... the red/black ones were previously fired pieces that i did not like so i broke them up and refired into various size cabs/blobs, then they were tossed into the saucer for the hi-fire .... all taken up to 1750 df and held for 1/2 hour (or was it an hour ???)

they are used for misc. decor - spoon rests - votive candle bases - coasters - whatever ... might get remelted or cut up or who knows ...

http://www.ibnutty.com/images/glass/hifire_4148.jpg
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gthomson
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Re: Nutty,Dave pics .... high-fires, pot melts, etc

Post by gthomson »

Nutty,Dave wrote:I did another high fire experiment but this one partially failed ...
OK, maybe this is one for Lauri's dictionary: What's 'high fire'? I'm guessing 'anything hotter than fusing', but I'd like to get the jargon right.

Thanks,

Glenn
Judy Schnabel
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Post by Judy Schnabel »

Dave,

I like the display of all the melts you did.

When you say they are in the clay trays with a drop of glue, do you mean this is the way you actually use them? I'm assuming these are not the trays you melted the glass in :?:

Judy
Nutty,Dave
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Post by Nutty,Dave »

(to Judy) ... true - the clay saucers shown are not the ones i fired in (since they have kiln wash all over them) ... it was easier to use new ones.

at the moment the glass is secured to the saucer with a dab of hot glue ... i did not want to permanetely glue to two together and this way i can take the glass out with minimal effort (and the hot glue blob pops off clean) ... i just wanted enough to keep the glass in the saucer ... i had tried wax but it was more work to clean up.

as far as use ... i am showing them to ppl more than using them but i do have a couple near my stove (spoon rests, etc) ... my wife has a few around with votive candles on them (some have just the candle, some have candle and clear votive holder, some have those little tea candles in their little metal cup) mainly to protect the countertops from heat ... the larger ones work well as drink coasters since the clay saucer holds any condensation that runs off the drinking glass (cause the glass disc wont absorb it)

still thinking of what else to use them for but i like firing the blobs in the saucers since i know they wont spread - are easy to put in/take out of kiln - and the small saucers (2.5") are 39 cents so my budget likes that.


(to rdguy) i dont know if high fire is an official term but you are correct in that it is higher than fusing ... i take them up to 1700-1750 df and hold for a while so the molten glass can bubble and swirl around enough to mix up the colors ... i learned about this process on this website and it has been fun to do as well as ending up with a pc of glass that looks more unique.


gotta go but i will post some more of these hi-fires later ... along with some pot melts that came out kinda cool.
Peace Through Art !!!
gthomson
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Post by gthomson »

Nutty,Dave wrote: (to rdguy) i dont know if high fire is an official term but you are correct in that it is higher than fusing ... i take them up to 1700-1750 df and hold for a while so the molten glass can bubble and swirl around enough to mix up the colors ... i learned about this process on this website and it has been fun to do as well as ending up with a pc of glass that looks more unique.
Thanks. The saucer melts are pretty cool, and look like a good way to ease into high fire.

Cheers,

Glenn
Judy Schnabel
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Post by Judy Schnabel »

Dave,

Couple of questions/comments:

After seeing your way of using scrap glass I went to Wal-Mart to purchase some of the saucers. This is so much more efficient than a pot melt in that I was able to get two larger saucers and 10 small saucers in one of my kilns. (Yes, I had enough scrap to fill all of them and some left over.)

I fired AFAP to 1750 and held for 30 minutes then annealed for 60 minutes then 150 to 700.

What was strange was that all the ones I did with scrap from one bowl turned out beautiful. The other saucers which contained scraps from another broken bowl all cracked.

Now here's my questions:

1) Someone, during a discussion on pot melts, said to use the clay only one time. Have you used them more than once?

2) I think the ones that cracked should have been annealed longer. I didn't realize how thick these little buggers would be. How long do you anneal yours?

Again, thanks for sharing your pictures. They are so neat and such an efficient way to use scrap.

Judy
Nutty,Dave
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Post by Nutty,Dave »

(judy) i have used the clay saucers more than once for normal fusing but i dont think i have used them in high fires more than once (but will) ... i have not had any crack but they do tend to 'flake' a little & stick to bottom side of glass ... but i grind that off for now.

how long to anneal ... kinda forget - i'll go check my kiln computer.
Peace Through Art !!!
Judy Schnabel
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Post by Judy Schnabel »

Dave,

Since I posted my last question to you I used a bunch more of scrap glass, plus refired the ones that cracked. And I fired these in the saucers I had previously used.

I did not go AFAP to 1750 and I annealed a lot longer. No cracks at all.

Thanks for sharing another way to use our scrap glass.

Judy
daffodildeb
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Post by daffodildeb »

Dave, maybe I'm missing something here (likely), but why can't you do the melt in the saucers WITHOUT kilnwash and save a step? Or is there a COE difference and the kilnwash provides a little "give? :?
Deb
Nutty,Dave
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my reply to questions asked ....

Post by Nutty,Dave »

I was emailed a question and after i responded i realized others might benefit from the ? and answer ... so i am posting it here.


(the question:)

Yesterday I decided to try some of your saucer melts with some
scrap instead of toss it. I had some success with pot saucers 4 inches
across at the top and not with the next size up. The little ones had a
little sticking of the saucer to the glass. The bigger ones stuck to the
saucers and cracked when I took them out. I did kiln wash the saucers.
Here is my question. Do you think I should use thinfire in the bottoms or
maybe talc along with the kilnwash? I love the idea of them and they are
really cool. Any help you care to share with me would be great.


(my reply:)

Did the clay saucers crack or the glass that was in them ???

If it was the saucers ... look at the cross section of the cracked clay and
see if it is pure clay ... some makers of the saucers cut costs by putting a
layer of ???? in the middle of the clay (or rather, they dip the cheaper
saucer in a clay terracota slip so it makes a sandwich of the two materials
... the cheaper layer usually looks gray or black, not red clay colored ...
if that is the case try to find different saucers (try another store) ...
maybe buy just 1 and then break it to see if it is solid clay.

if it was the glass that cracked ... keep in mind the clay is fairly porous
and can absorb lots of kiln wash ... so maybe it absorbed too much ??? i
tend to pour the kiln wash into the saucer (to the rim) and let it sit for
10-15 minutes ... then pour off the excess ... this leaves a thicker coat of
kiln wash (more than i would use on my shelf) but i usually grind it off
later.

i also tend to use more solid than transparents because of the clay / kiln
wash sticking and i know i have to grind off later ... sometimes i refire on
a shelf to let the 'blob' flatten out and fire polish and then use that as
is or slump into something else (or cut and collage into another piece)

thinfire works for fusing temps but i have not tried it for any hi fire
melts ... i am not sure if the glass 'movement' would pick up the paper and
mix it up.

i have no experience with talc so my guess would be the same as thinfire ...
okay for normal fusing but maybe too much mixing for hi-fires.

let me know what works for you ... have fun,
david

ps: i am still experimenting with the saucers but they have helped ... i use
them quite a bit for turning tiny bits into rods & buttons ... which are
later tack fused (or full fused) onto/into other projects .... but i can
arrange and space outside of the kiln and then carefully place the whole
thing into the kiln ... as well as easily removing all the little bits.
Peace Through Art !!!
lohman
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Post by lohman »

Nutty Dave,

I have a problem with your assessment of the nature of the dark core of the broken saucers. Do all your broken saucers show this dark core?

You said you thought the dark core was the result of the manufacturer cutting production costs by dipping a cheaper clay into the terra cotta clay.
I think adding a step in the production process in making these saucers would cost more that making them out of one clay.

Can you post a pic of the broken edges of the saucers?

What I think is happening here is a reduction/oxidation thing. What makes the terra cotta red is the presence of iron oxide in the clay.
Look at rust on a piece of iron: it's red too. When the terra cotta is fired in a kiln with lots of oxygen (an electric kiln?) all the oxygen in the iron oxide ramains in the clay body resulting in a red-boddied terra cotta saucer. An electric kiln fires in an oxygen-rich atmosphere with no flame. However there can be localized reduction in an electric kiln when the there is enough organic material in the clay. The carbon procuced by the burning organic material gets trapped in the clay. That is called a body reduction. Potters who fire with combustable fuel like wood, gas, or oil, intentionally create a reduction atmosphere in their kilns by over-loading the fire with fuel. That brings out certain colors in the clay and glazes that have various oxides in their composition.


When that same terra cotta clay is fired in an oxygen-starved kiln (gas, oil-fired kilns have combustion and flames) the fire eats up all the oxygen it can get for combustion including what it can take out of the clay leaving the iron in the clay without oxygen or put another way, back in it's non-oxidised state. Like iron which is not rusty--ie. black or gray.
The Hobbyist
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Post by The Hobbyist »

lohman wrote: I have a problem with your assessment of the nature of the dark core of the broken saucers. Do all your broken saucers show this dark core?

You said you thought the dark core was the result of the manufacturer cutting production costs by dipping a cheaper clay into the terra cotta clay.
I think adding a step in the production process in making these saucers would cost more that making them out of one clay.
I can't comment of whether or not this is the problem but I can assure you that some cheap "terra cotta" pots are not solid clay of the same type. When I am enlarging the hole at the bottom, with a rasp, I've noticed that the edges of some "opened" holes reveal/expose a different material. It greatly resembles cement in color. The pot functioned as I wanted so I was unconcerned but it was NOT solid terra cotta.

Jim
"With or without religion, good people can behave well and bad people can do evil; but for good people to do evil—that takes religion. " Steven Weinberg
lohman
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Post by lohman »

'tis a mystery.
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