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The Newsletter for Raku Artists and Raku Art Lovers
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October 2004
Issue #24
Published by
Gary R. Ferguson - Raku Artist
http://www.garyrferguson.com
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In This Issue
* While the Smoke Clears - 2nd Anniversary and $p@m
* From The Studio - Spinning and Burning
* Article - In the "Thick" of it
* Tips/Techniques - Glaze Results Have Changed
* Q&A - No Cones?
* Glazing - Hawaiian Copper "Blues"
* Reader Feedback - You said it.
* Calendar - Not much left for 2004
* Click Away - Raku on the Internet
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* While the Smoke Clears *
Second Anniversary!!!
That's right - the Just Raku newsletter is two years old this month!
And I must say, much better behaved than my two-year-old son. J
Speaking of my son, he showing potential of being a potter too I guess.
Every time I'm in the studio working, he has to have his own piece of clay
too. He is such a mimic at this age, I really have to watch what I say and
do.
To celebrate the "birthday" I'm going to give away a 2 copies
of my Raku Glazes eBook. Watch your inbox for how to enter this special
drawing.
On another note, I have been receiving a ton of "email delivery
failure" $p@m. This is usually the result of someone having a virus
with my email in his or her address book. If your PC seems to be running
slow, please run a virus check on your machine and see if you've got one
of these types of virus.
This also means if you have sent me an email over the last couple of
weeks and did not get a response please try again.
Remember I always look forward to your feedback, suggestions,
questions, and article ideas at: mailto:editor@garyrferguson.com.
Gary R. Ferguson
- Raku Artist -
mailto:pottery@garyrferguson.com
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Here is an easy (and free) way to support this newsletter. Open a new eBay
account by clicking on the link below and select "register" at
the top. Then bid on something, anything. You don't even have to have high
bid. Your "clicking" will be very much appreciated. http://www.qksrv.net/click-411938-2202639
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* From the Studio *
Still Throwing - Still Bisquing
The wheel has been a spinning and the kiln a burning the last few weeks
getting pieces ready to Raku over the next couple of weeks. I'm still
getting pieces ready for the Beaux Arts show that will take place during
the first week of November at the Boise Art Museum.
EBay
I've starting listing a few items on ebay again with mixed results. I'm
guessing as the holiday season approaches this will pick up.
New eBook
I'm also working on the final edits of a new eBook called "Raku
Secrets" which I hope to have available sometime next month. Stay
tuned!
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If you are interested in making a little extra money for taking on-line
surveys, click on the link below. I've made about $100 in the last month
or so. Go to http://www.surveysavvy.com/?id=1424287
and click on 'Join'.
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* Article *
In the "Thick" of it
The thickness, thinness, and consistency of the clay walls of a vessel
can greatly affect both the survival rate of the piece and also glaze
result. As the piece is heated in the kiln it expands and as it cools in
the reduction chamber it contracts. The thicker the walls the slower the
piece will heat or cool and conversely the thinner the walls the quicker
the piece will heat and cool.
If a piece is consistently the same thickness, the entire piece will
generally heat and cool at the same rate and hence expand and shrink at
the same rate. If on the other hand, the walls of the piece are thicker in
some areas and thinner in other areas, these sections will heat and cool
at different rates which will also expand and contract at different rates.
This difference in expanding and contracting rates can cause pieces to
spilt, crack, or break. So, if there is a great variety in the thickness
of the walls of a piece, fractures in the walls and joints could occur
during the heating and cooling process.
There are two possible solutions to help the "survival" rate.
The first solution is obviously to make pieces with as consistent walls as
possible - either thick or thin. This will help the "whole"
piece expand and contract (heat and cool) at the same rate.
The second solution can help in the case of an inconsistently thick
vessel. In this case the piece should be heated and cooled slower so the
uneven walls are not stressed as much. The piece may have to be fired
slowly (2+ hours) to temperature and then allowed to cool longer (45+
minutes) in the reduction chamber before it is dowsed with water.
The thickness and thinness of the piece can also greatly affect the
glaze - especially glazes that are highly affected by the reduction
process. If the piece is thicker it will cool slower so it is easier to
conduct a heavy post-firing reduction (more on this later), because the
piece can be placed in the reduction chamber before it cools very much.
This enables obtaining solid copper colored pieces with glazes that
contain copper carbonate. Contrarily, the thinner the piece the quicker it
will cool and the more difficult it is to obtain heavy post-firing
reduction so one is more likely to obtain non-copper colored pieces (blue
or green).
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Raku: A Practical Approach by Steven Branfman
The "nuts and bolts" how-to book of Raku
Order 30% off at: http://tinyurl.com/8m5k
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* Tips and Techniques *
Glaze Results Have Changed
[Gary]
I read your Raku newsletter and find it very helpful.
I've been Rakuing for the past 8 years. This year my glaze results are
disappointing. I'm not sure what is going wrong. I've made the same glaze
recipes but they're all coming out dark colors...none of the beautiful
purples, blues and reds I had in the past. The only thing I can think of
is that the gas (propane) going into the kiln is not getting enough
oxygen. Is it useful to use an oxygen atmosphere-testing instrument? Isn't
reduction of oxygen necessary in the firing
Thanks,
Sharon Z.
Hi Sharon:
Not knowing your exact situation, I can only provide a few general
tips/thoughts.
Typically to get colors (copper, reds, etc.) you need reduction, either in
the kiln, or in the post firing reduction process, or both.
I typically fire in oxidation and then focus on post firing reduction, but
I do know there are some glazes that need to be fired in reduction to
obtain colors.
Some other things to try - fire hotter (or slower) and apply the glaze
either thicker or thinner.
Also, have any of your chemical supplies changed or are you using a
different water source (I knew a guy that used very iron rich water that
caused all glazes to go brown)?
I've never used an oxyprobe for Raku. Usually you can tell if you are
firing in oxidation or reduction by the sound of the burner and the
flame/smoke from the flue of the kiln. That's usually enough in my
opinion.
Hope this helps.
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* Q & A *
Q: Do you have the cone ratings for the Raku recipes on your site? I
could only find a couple with the cone listed.
A: Almost all Raku is fired to around 1750F to 1850F. Since the firing
is so rapid most glazes have to be visually inspected to determine
maturity so cones aren't actually used much.
300+ Raku Glazes can be found at: http://www.rakuglazes.com/
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Raku: Investigations Into Fire by David Jones
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* Glazing *
Hawaiian Copper "Blues"
I tried your Hawaiian Copper Blue recipe, expecting to get a nice
golden red like you did one your ribbed pots, in the misc. Vases section
of your gallery. But I got a really matte grainy blue. What do I need to
do to get a deep glossy red?
If you are getting a matte blue using Hawaiian Copper Blue you need to
do two things:
1) Fire hotter (or soak longer) so the glaze matures more and you get a
semi-glossy finish.
2) Either fire in reduction in the kiln or do a heaver post-firing
reduction to get the copper and burgundy colors.
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Raku Pottery by Robert Piepenburg
The must have "Bible" of Raku
Order at: http://tinyurl.com/8m5b
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* Reader Feedback *
Hi Gary,
I have been a Rakuist for about 10 years now. I have enjoyed your
newsletter and have found food for thought and good tips.
I agree with your advice, often given, test & experiment, test &
experiment! Since materials change slightly, or more, between batches, it
is important to run tests to insure the batch does not change the
character of the glaze or process.
One should remain loose, creative and even wild and outrageous in order to
make art. Put fear of the unknown out of your vocabulary.
Keep up the good work Gary.
Charles W.
Hi Charles:
Thanks for the feedback on the newsletter.
I'm glad you have picked up on the reoccurring theme that one of the main
tasks of a potter is tester - both in testing glazes and in testing new
ideas in clay.
Gary F.
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Dear Gary,
Thank you for your great newsletter. It is always a joy to receive and
read. I see in the latest newsletter you have some substitutions for
Gerstley Borate. At the Potter's Council Firing Workshop last summer in
LaCrosse, WI., I was told that a potter had substituted Gillespie Borate
for Gerstley Borate and saw no discernable differences. I tried it. Big
Mess! I mixed a batch of pale lemon luster and pale aqua luster, along
with a batch of white crackle using the Gillespie borate. All three of
these recipes I have worked with for years. It appeared to me that the
glaze went directly from heating up to a boil. I could not find the fine
glass sheen prior to the boiling happening. Needless to say all of my
pieces were ruined. I attempted to fire slower but it did not help. I
attempted to fire at a very low temperature and then the glazes did not
mature at all. I have since mixed the same three glazes using Gerstley
Borate and they were beautiful. Could it be the Gillespie Borate, and if
so, why? It is the only known variable I could think of. Also, I now have
a lot of Gillespie Borate and can find no recipe to use it in. Do you
think any of your reader's could help me find one?
Again, thank you for your time and energy to make this newsletter happen.
Sincerely,
Julie N.
Hi Julie:
Sorry to hear of your disappointing experience with Gillespie Borate. I've
not used that substitute yet so I don't have any personal feedback. I
would assume the substitution success could be affected by what percent of
GB is used in the glaze. A glaze with 90% GB may be affected more with a
substitute than a glaze with just 20% GB.
Another thought on your "boiling" glaze is to potentially let
the glaze soak a little longer. There are several glazes I use that appear
to "foam up" during the firing and then smooth out as they
mature, so I don't know if this is the case with the Gillespie Borate
substituted glaze or not.
Any Just Raku readers successfully using Gillespie Borate? Care to share
your recipes and results?
Thanks,
Gary F.
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Gary,
In regards to the cream crackle, I've noticed when using a white crackle
and I cool it fairly quickly, dunking in water, after post reduction, and
when the piece is still hot, the white will turn a beige color. I suggest
trying to cool the piece more slowly allowing it to stay covered for a
longer period of time in the post reduction [chamber]. I've noticed this
with 3 different clay bodies, one is "Raku II" a white clay body
from Seattle Pottery, but this is only what I have experienced. Give it a
try and I hope this will help. By the way thanks for the newsletter it is
nice to hear from people from all over.
Scott
Hi Scott:
Thanks for the tip on getting a "white" crackle instead of
beige. Hopefully this will solve the other readers problem.
Gary F.
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Dear Mr. Ferguson,
I purchased your ebook on Raku glazes this morning. We tried some of the
free recipes on your website yesterday and the results were fantastic! The
best I have achieved to date. Thank you! Looking forward to receiving the
book.
Thanks again,
Jeff B.
Hi Jeff:
Thanks for your purchase and I hope you are enjoying the Raku Glazes
eBook.
You of course can purchase your copy at:
http://www.rakuglazes.com
Thanks
Gary F.
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Dear Gary
Most interesting as always with useful tips. Great effort and very
appreciated.
Ana
Hi Ana:
Thanks, and make sure you forward a copy of the newsletter to all your
potter friends and ask them to subscribe as well.
Gary F.
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[Gary]
I have been doing Raku for 14 years now and fire 30 to 70 pieces a week.
Now some health issues have come up, as I haven't wore proper safety gear.
I do not throw, so clay dust is not an issue for me, but [if] you do …
take care on the clay dust.
In my blood work levels of Arsenic, Strychnine, Mercury and Zinc are at
dangerously high levels and causing headaches, blurred vision and body
pain. I have to go through Chelation therapy and wouldn't wish this on
another artist.
I cannot stress how important it is to use proper safety gear, mainly a
respirator while firing. Newsprint is set with arsenic, but so are the
catalogs I have opted for. When reducing patina glazed cobalt is in the
fumes, this will cause cancer.
I am dealing with the safety officer from Nevada Power & Light to find
the proper filters to use in a respirator to filter out these poisons.
When he has come up with the right material for me I will pass on the
information.
Please, please, please, wear you safety gear and drink a lot of water. Use
oxygen if you take a dose of smoke.
Please care for your self so we may all enjoy your art for many years to
come.
Thank You,
Janet P.
Janet:
Thanks for the tips on protecting us from the dangers associated with
pottery, and good luck with your treatments.
Gary F.
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Gary,
Do you use anything to seal the inside of vases so that they are
functional? Is there something available? [I] Enjoy your newsletter.
Thanks,
Nancy
Hi Nancy:
Check out the following two past newsletters about sealing Raku:
http://www.garyrferguson.com/justraku22.htm
http://www.garyrferguson.com/justraku06.htm
Thanks.
Gary F.
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* Calendar *
My show calendar for 2004 will probably be smaller than in the past. I
only plan on doing two or three shows, but spending more time focusing on
eBay sales. This way I can spend more time with the family and less time
sitting in a booth.
Nov - Beaux Arts Holiday Show
TBD - Studio Open House
On going eBay Listings http://tinyurl.com/tn08
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Advertise your Raku products or services here to reach over 1200 Raku
Enthusiasts for only $5 per month. Includes URL, email address and four
60-character lines. For details contact: http://advertise@garyrferguson.com
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* Click Away *
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Just Raku Newsletter Archive
The past issues can be found at http://www.JustRaku.com
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JUST RAKU (C) Copyright 2002-2004, Gary R. Ferguson
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