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Post by Peter Sorensen on Oct 24, 2015 13:35:59 GMT -6
Hi All I have finely got my gaskiln in operation, So I have now the possibility to fulfill my dream on gold stuf. a beutiful golden crystal on blue back. On the old forum there was a tread on goldstuff 5% rutile and 3% ilmenite in a 3110 glaze I have now tryed in tree trials, But it seems to come out in 3 version of pale army green It is obvius that I am dooing it wrong som where in the process I reduce from 1010 C down to 900c in my gaskiln in a second fire I hope there is one here on the forum that can help me  I have tryed to put in a picture but not shure if it works Peter |
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paul
Junior Member
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Post by paul on Oct 24, 2015 18:36:06 GMT -6
Try 800 C down to 700 C ...in that range. 1000 C down gives a different color group
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Kuba
Full Member
SztukKilka in Old Formu
Posts: 111
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Post by Kuba on Oct 25, 2015 2:43:11 GMT -6
I always doing reduction at max 700C-750C, never tried to go higher  |
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Post by jfox on Oct 25, 2015 9:52:44 GMT -6
 750 C reduction singlefire in a gas kiln |
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Post by Arnie Benton on Oct 25, 2015 11:13:21 GMT -6
I'm interested to see what happens when Peter tries reduction at the lower temperature. I agree with what others wrote, but I have reduced at higher temps and the Ti has always turned purple. I'm wondering if Peter is getting sufficient reduction atmospheres.
That's a beautiful piece, Jim -
Arnie
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Post by jfox on Oct 25, 2015 11:27:23 GMT -6
at 700 to 750 you get no smoke just pure carbon monoxide so i ignite the gas with a torch at the leaks and when i can support combustion at the bottom of the door or out the bottom of the kiln i know i have complete reduction i use about 10 to 15 minutes rutiles need more at this low temp.
below 700 ive got small but intimidating detonations when turning on the propane so now i handlight the first burner on low then the rest
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Post by Peter Sorensen on Oct 26, 2015 12:49:13 GMT -6
Hi All Thanks for your response om my problem. First, when I do the reduction I close the out vent on my kiln to my ECO probe goes to around 0,9 volt, and the outvent ignite With a small flame I then reduce the gas input on both burner that are tuned to a neutral flame (there is no black smoke anywere) but I then reduce the temp from 1010 C down to ca 900C I have some lithium aka spodumene in my glaze so I gess that it is more fluid longer down in temp than if I no lithium in the glaze. I have done a quick kalkulation on the Tio2 in the glaze is around 6% is that to much ? the glaze react well to the reduction with a big color change just not to what I have hoped   this is a picture of my army color collection But I will try to do the reduction at a lower temperature Can I just re do the reduction as they are ? Peter |
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Post by mohawkpiper on Oct 26, 2015 13:29:28 GMT -6
In my opinion, no, you cannot just re-reduce at lower temps and expect it to work the way you had hoped. In taking it to 1010 in a second firing you essentially did a high strike and i believe that alone had more of an effect on your glaze than the reduction. Also I believe it is non reversible.
You can obviously try it and see though. Maybe it will work for you.
I am in agreement with the others, if you are going to post fire your reduction it is better to stay below 800. If you want to reduce higher than that then it is best to reduce on the way down in the initial firing.
Obviously you can reduce that high in a post firing, and you can get some very nice results, but i believe just the strike alone is doing most of the color changes at those temps post fire and it wont be what you are used to seeing from others.
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Post by Avi on Oct 26, 2015 16:50:32 GMT -6
I use a FF413 base with the same oxides and reduce on the way down during my glaze fire at 2000ºF (1100ºC) during the last of 3 holds for about 1 hour.  |
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Post by tileman2 on Oct 26, 2015 21:03:33 GMT -6
Peter:
Got any pictures of the catchers that were attached to the pieces you posted? Three pieces in three different firings, ending up with three different color variations. The piece on the left, I see familiar rutile color on the neck only. The middle piece is pale in color in comparison to the other two. The piece on the right has deep ilmenite colors in the neck, but pale elsewhere. Fluidity is just one problem.
Interesting that high up on neck of the pieces where the glaze is applied thicker, you are coming into color range. Then on the shoulders on down there is dramatic color loss. The middle piece is baffling, almost perfect color uniformity from top to bottom: even though it is out of range. My guess is that your catchers have a very dark glaze pool.
Nice bowl Avi- very nice.
Tom
Edit: afterthought- zinc is changing, feldspar is changing, frit and clay changes. Wondering if potency levels of flux is also changing, or sources for flux is changing.
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asr
New Member
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Post by asr on Oct 26, 2015 21:21:03 GMT -6
Would any one be willing to post an analysis of FF413 so I could compare it to the 4113 that we can buy in Australia.
Thanks in advance
Anne
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Post by Avi on Oct 27, 2015 12:47:35 GMT -6
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asr
New Member
Posts: 5
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Post by asr on Oct 27, 2015 22:46:01 GMT -6
Thanks for that Avi. Maybe I will have to order from the states. I can work out a recipe from that analysis but have no idea of the preparation that would be necessary to make it suitable for crystalline glazes.
Cheers
Anne
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Post by Peter Sorensen on Feb 1, 2016 17:32:07 GMT -6
Hi Arnie and all I think you are right arnie it was the reduction that were the problem I found that i have to follow my high fire reduction at 1010 Celcius down to 800 Celcius I have made a oxygen sensor of an old auto exhaust sensor and I have to get a reading of 0,7 - 0,9 volt in the cooling down to 800 celcius I gess that the glaze had stiffen enough so it dont take oxygen in in the rest of the cooling this and i have a hold time at 1010 celcius at 20 min so the glaze is molten enough so the atmosfære can drag out the oxygen out of the glaze I thank you all for your help it is gold to me Peter  |
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Kuba
Full Member
SztukKilka in Old Formu
Posts: 111
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Post by Kuba on Feb 2, 2016 15:20:44 GMT -6
Wow, amazing reduction Peter!
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