Marcia Selsor on wed 13 jul 05
I put my flat pieces face down on straw and cover them with a big
galvanized bucket. smaller pieces that fit into a garbage can
sometime go there but I like the straw pattern.
If you are not covering them, they may be cooling too fast and not
getting a good reduction. If you have "Advanced Raku Techniques" from
CM there are pictures from an old article from CM May '97 showing
the whole process. I find the big buckets work really well. Sometimes
corners or edges stick out from the buckets and that can get some
interesting variation of color. I think your avocado color comes from
not a good reduction.
My flat pieces are thicker (over 1/2 an inch thick to 5/8 inch) than
thrown pieces so it may have to do with thickness and heat work on mass.
Marcia Selsor
On Jul 12, 2005, at 8:34 PM, Jane Murray-Smith wrote:
> Thanks Marcia for your input.
> I was going to put in cone 08 cones tommorrow to check out the temp.
> My glaze is old... I do put it on thin...
> and I don't burp...so lots to try
> Any theory as to why the flat pieces are the victims of this, and
> not the
> thrown forms?
> And do you put the pieces into the metal container, or do as I do,
> which
> always has damp cedar right under the new dry nest of cedar and
> shredded
> paper
>
>
>> Jane,
>> found your question
>> I have been firing flat pieces for for about 20 years. Here is what
>> may be happening
>> 1. glaze could be on too thin
>> 2. try "burping" the reduction to get some air in. I find that tends
>> to bring out the color.
>> 3. glaze may be old. I always mix a fresh glaze within 2 weeks of
>> firing. I store the glaze dry and then mix small amounts as needed to
>> guarentee freshness.
>> 4. You may want to go a little hotter. I was taking mine to 1850.
>> WHen I did 1825 I got muddier colors.
>> 5. your pyrometer may be slipping. Try firing a bisque and use your
>> pyrometer and match it to a witness cone to recalculate.
>>
>> Hope these help.
>>
>> Marcia Selsor in hot Montana
>>
Jane Murray-Smith on wed 13 jul 05
Oh yes, I cover them..and if the blackness of the unglazed areas is an
indication of reduction..I get very good reduction.
And my experience with really thick pieces like you are talking about is
that those surfaces often end up with pale gold and pink patches!(that ,
like the avacado, and mud families, don't look right in the rest of the
glaze) My intuition is to think 'too hot', but that is probably wrong.
I am also going to watch very closely when I raku today (or tommorrow), as I
believe that as I watch the color start to move over the copper (as the
flames are in full burn before I cover), I can actually see slightly darker
patches...I'm thinking tha they are what turns into the mud.. How that will
help is questionable, but...
I'm really hoping that the problem is not enough heat...but if I go by the
color of the pieces when I lift the kiln...sometimes I wonder if I'm too
hot..we're heading towards yellow..in fact I have other glazes that I can
burn at the temperatures that I will fire this contentious glaze
Anyway, thanks for your ongoing feedback.
Take a look at my site to get an idea of what I am capable of when the raku
gods are smiling on me.
www.dragonflypottery.ca
Jane
----- Original Message -----
From: "Marcia Selsor"
To:
Sent: Wednesday, July 13, 2005 6:39 AM
Subject: Re: Desperatley seeking raku guru/some answers
>I put my flat pieces face down on straw and cover them with a big
> galvanized bucket. smaller pieces that fit into a garbage can
> sometime go there but I like the straw pattern.
> If you are not covering them, they may be cooling too fast and not
> getting a good reduction. If you have "Advanced Raku Techniques" from
> CM there are pictures from an old article from CM May '97 showing
> the whole process. I find the big buckets work really well. Sometimes
> corners or edges stick out from the buckets and that can get some
> interesting variation of color. I think your avocado color comes from
> not a good reduction.
> My flat pieces are thicker (over 1/2 an inch thick to 5/8 inch) than
> thrown pieces so it may have to do with thickness and heat work on mass.
> Marcia Selsor
>
>
> On Jul 12, 2005, at 8:34 PM, Jane Murray-Smith wrote:
>
>> Thanks Marcia for your input.
>> I was going to put in cone 08 cones tommorrow to check out the temp.
>> My glaze is old... I do put it on thin...
>> and I don't burp...so lots to try
>> Any theory as to why the flat pieces are the victims of this, and
>> not the
>> thrown forms?
>> And do you put the pieces into the metal container, or do as I do,
>> which
>> always has damp cedar right under the new dry nest of cedar and
>> shredded
>> paper
>>
>>
>>> Jane,
>>> found your question
>>> I have been firing flat pieces for for about 20 years. Here is what
>>> may be happening
>>> 1. glaze could be on too thin
>>> 2. try "burping" the reduction to get some air in. I find that tends
>>> to bring out the color.
>>> 3. glaze may be old. I always mix a fresh glaze within 2 weeks of
>>> firing. I store the glaze dry and then mix small amounts as needed to
>>> guarentee freshness.
>>> 4. You may want to go a little hotter. I was taking mine to 1850.
>>> WHen I did 1825 I got muddier colors.
>>> 5. your pyrometer may be slipping. Try firing a bisque and use your
>>> pyrometer and match it to a witness cone to recalculate.
>>>
>>> Hope these help.
>>>
>>> Marcia Selsor in hot Montana
>>>
>
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