Janet Holdcraft’s Blue Dawn Glaze

, , , ,

bule001

While looking for a glaze cost savings and going though our glaze raw materials  I realized I had a few opportunity areas.  I try to review the raw material pricing  every six months to keep the prices of my pots at a level for the local area while also maintaining quality.  I was taught to hand mix glazes and always have, only buying premixed glazes for special projects in very small amounts.  To make it cost effective it is important to have as few raw materials as possible while still maintaining the safety of the finish wares.

The Search For A Glaze

In the past I have seen some glazes have six to eight raw materials.  If a pottery were to have five or six glazes each using different materials the cost for maintaining the glaze recipes and raw material storage can rise creating loss in studio space, storage space, and grow into a large financial burden.  All of this adds up over time, driving up the cost of the finished product.  So I set out to correct some of the issues by looking for a low material glaze that would have a wide firing range.

Since I fire to cone 6/7 in an up draft gas kiln, the top of my kiln is always cooler.  I hit a cone 7 on the bottom, cone 6 in the center, and the top a cone 5.  With my old glaze I would sometimes loose the top shelf of pots to under-firing.  If I fired longer  to make the top of the kiln warmer, the temperature on the bottom would over fire and vitrify the pots.  That ‘s why I was happy to find the “Blue Dawn ”  recipe on the Facebook pottery group.

Janet Holdcraft’s “Blue Dawn

janet

“Blue Dawn”, was created by the late ceramic artist and teacher Janet Holdcraft donated by her friend and colleague artist Jerry C. Williams Sr.., who put the glaze “Blue Dawn” in the public domain.  Hearing about Janet from her good friends Jerry Williams and his wife  Lea Ann Nall-Williams , I found Janet to be an amazing person who was loved very much by her students and kept very good records of her glaze research.  I have included part of the post below:

The blue glaze used on this piece was created by Janet Holdcraft and she loved her bubbles. This is Janet’s recipe we are calling it Janet Holdcraft’s Blue Dawn. Base glaze 2500 is EPK of 500 grams, Flint of 750 grams, and Gerstley Borate of 1250 grams with 5% or 125 grams of Cobalt Carb. She has a whole page of trial and errors and this is the last one on the page with a * and a “YES” we have her book and it is a treasure. Thank you Janet for all the good you did in this world. This is for the last few Good Will Friday’s that I have not posted but the good you showed to me and Jerry will never be forgotten. RIP Lea Ann Nall-Williams. Clay used is 50 pounds of premix with 5 gallons of reclaim and red art added to the mixture there are also other things he adds but trying to get him to measure anything is as impossible as getting Jerry C. Williams Sr. to post of facebook. Posted by Lea Ann Nall-Williams. I use to be there sometimes when she mixed her glazes she was very percise and on a mission.”

After seeing the post I gathered the raw materials and hand mixed a 100 gram batch as a test  and gas fired out the glaze in my test kiln.  The results for such a simple recipe were quite amazing.   I was able to make the full range I needed with zero loss from glaze defects which was a huge relief.   I was quick to show Jerry the results and took images off my coffee table.  The poor lighting did not do the glaze color justice, but the blue shown through just beautiful enough to cause excitement.

bluedawnoo2

A Janet Holdcraft Tribute

So after I was pleased with the results I decided to try the glaze on a collection of shave bowls I had started.  And what better way to create a collection then to have it be a tribute to the person who made it.   It was amazing to think about how many artists, teachers, and craftsmen live far beyond their years in the work, research, and contributions they left behind.   I am proud to have the opportunity to mix this glaze and I am more than happy to post Janet’s recipe here so others may try it if they wish. Below is the recipe converted to a 100 gram batch:

Janet Holdcraft’s “Blue Dawn”

Gerstley Borate – 50
EPK. – 20
Flint. – 30
________________________________
Cobalt. – 5

If you have work with these stamps on the bottom,  or  your  citronella lamp has the “Mariposa Pottery” note seen below, then you may have a Janet Holdcraft piece.  Thanks very much to  Lea Ann Williams for sending in the images.

stamps001

 

stamp003

“Blue Dawn” – A Janet Holdcraft Tribute Collection

Below are some samples of the “Blue Dawn” collection.  The works maybe purchased while supplies last at  our Creek Road Pottery shop on Etsy

 

The artist Jerry C. Williams Sr. has inspired me with his work  and forced me to think about the bottoms of bowls as a whole new canvas begging to be worked with texture.  Jerry’s Native American inspired designs capture the native culture in very unique way.  On first seeing Jerry’s work  the patterns, textures, and drawings on the bottoms of his bowls made me appreciate all sides of the pots I was making and forced me to think about what other parts of the work I might be missing out on experiencing.  You can find Jerry’s ceramic work posted on his page or at the Green Door Art Gallery.  I would like to thank Jerry and Lea Ann once again for posting this recipe to the public domain and it was a pleasure to use the glaze and I’m sure many other artists, potteries, and ceramic lovers will enjoy using and seeing the glaze . If you the reader try this recipe please let me know how it turned out by posting a comment here with a link to a sample!  I would love to see where this might go!

Jerry and  Lea Ann,  if you are ever in PA  feel free to stop by and I’ll show you my little pottery!  Also thanks for the beautiful bowl you sent over to me.

Al Wayman
Creek Road Pottery LLC

/0 Comments/by

My Battle With Carbon Coring

, , , , , ,

20160822

Carbon coring or “black coring” can be an issue when firing clay bodies. While doing some experiments with reduction firings I had many pots that were cracking in the process and had no idea why. It seemed that the cracks were from fast cooling, as they were clean breaks through the glaze with sharp edges. Little did I know that this cracking was caused by carbon coring or “black coring”. I did some comparisons wth cross sections of the broken pots and noticed that this discoloration did not happen in my oxidation firings but only in reduction. I dug out my ceramic books and searched online to find out what this issue might be.

Shattered By Black Coring

While researching I found a post by the Lugna Clay company entitled ” Bloating and Black Coring”, which seem to suggest that I may need to bisque fire my clay body properly.  The theory behind the article suggested that not all the carbon was burned out of the clay body and the kiln also may need to be vented better in the bisque firing. The clay body I was using was AMACO high-fire warm brown 58-M stoneware clay. I only had issues with bloating when I accidently overfire it a few times on the bottom shelves while trying to reach cone 6 in the middle of the kiln.  The clay body was high in iron content which, I later found, created the issue with black coring when I reduced the updraft kiln to produce a body reduction. The iron in the clay and the reduction process was a bad combination and would produce a bad kiln load of pots.  Bowls shattered as they cooled.

Black Coring – The Cause

The answer to the problem came from an excellent research report entitled “Calcium and sulphur distribution in red clay brick in the presence of a black reduction core using micro X-ray fluorescence mapping”. by L.Gredmaier, C.J.Banks , and R.B. Pearce. These findings can be found on page 2 and 3 of this report:

“The following factors determine the extent of black reduction coring in red clay ware:

- Firing time – a longer ring time can eliminate the black reduction core.

- The oxygen atmosphere during ring. Lack of oxygen promotes the formation of black reduction cores.

- Iron oxide content in the raw clay.

- Carbon content and burnout or oxidation of carbon during firing of the raw clay.”

The research in this report stated also that the red iron oxide was converting to magnetite.

To the potter, according to “The Potter’s Dictionary of Materials & Techniques” by Frank and Janet Hamer, on page 26,  means this conversion created weakness to the clay body caused the clay to vitrify at a lower temperature due to the red iron oxide and carbon converting to black iron oxide and carbon dioxide, which creates an active flux . The pots become brittle and fragile.  One mug I took from this load popped apart while I poured coffee in it as a test, sending shards across the table, because it could not withstand the thermal shock due to black coring.

Black Coring – The Solution

The solutions to black coring from the article link to above would be to use a clay body with less iron content.  Also, it is suggested that bisque firings should be slower and to the correct temperature to allow carbon burn out.  I personally found that in my high iron clay body, if I skipped the body reduction of the firing and reduced the kiln towards the end of the firing, I still got reduction glazes to look great without black coring.

If any of you who read this have found this helpful or have your own findings, feel free to leave a comment!

 

 

20160512_185726
Al Wayman
Artist /Owner
Creek Road Pottery LLC

 

 

 

 

 

 

/0 Comments/by

Firing The Amaco AG40 Updraft Kiln

, , , , ,

View post on imgur.com

Firing out the Amaco AG40 is great for raku , but I sure had issues with the higher temperatures.  When I was working towards my degree and also was an apprentice at a pottery when I  found a little Amaco AG40 updraft kiln in the classified section of the paper.  The kiln was owned by older gentlemen and hobby potter about two hours from where I lived.  This gentleman had the kiln installed above his garage he was using as a studio.  He had a ventilation fan that came with the kiln and everything was in great condition.  A family member and I loaded this little kiln onto a truck and carefully drove it home.

The kiln had no instruction manual, and we had to learn how to light it from the label on the side.  We had the gas company bring out two tanks and connected both with 2 lines running into one hose with a connection to the regulator.  After following the directions, we were able to fire the burner and bring the kiln to life. That summer, and for the next two years would use the little kiln to run a raku line of pots.  Those were the best summers.  We ran a Spring and Fall show with demonstrations for the public.  It was three days of fire, smoke, and pottery.

 

View post on imgur.com

Dusting off the AG40 Updraft

After graduating with a B.F.A. in Ceramics and leaving the pottery, I put all my equipment into storage. I had to find work to pay off student loans.  When my wife and I bought our home, I put in a small clay studio with the encouragement of friends and family who were into the wet shaving hobby.  These friends wanted lather bowls and brush handles.  I hooked up my little Amaco Kiln again and looked online for a manual. Amaco was able to send me an old manual.   I only fired this kiln to a midrange temperature with this kiln once but could not remember the schedule to repeat it.  The manual had a suggested firing schedule, so I started tinkering.

I had the gas company come and hook up a tank large enough to prevent freezing.  The first few firing were terrible simply because I was not able to properly regulate how much gas was going to the kiln’s burners and I had a broken gauge.  I started with a simple bisque fire but knew I had to make some repairs before I went to a full first firing.

At times I was almost ready to roll the kiln over the bank.  I had a whole cone or more difference in temperature between the bottom and top, with the bottom shelf being hotter.  The kiln would also stall out.  So I saved up some money and bought a converter kit.  The kit had a stand with an updraft burner which allowed hookup to a twenty-pound propane tank.  This helped out a great deal because I now had more control over the amount of gas and temperature of the kiln because this had a gauge that worked.

With the conversion kit, I now went back to square one and used the firing schedule out of the manual and completed a midrange firing.  I still had a large temperature difference between the top and bottom.  To fix this issue, I widened the glaze firing range so that the top of the kiln would not fall under fire.  I was able to get a few good pots using this method; that is until I accidently overfired on Christmas day.

Over Firing The Amaco AG40

Meet the Kilns

On Christmas Eve 2015 I prepped and glazed a load of shave bowls that I wanted to have completed as Christmas gifts.  I wanted to wrap those gifts right from the kiln for dramatic purposes and hand them out a few days later. Glazing ran later than expected and the firing stalled out climbing to cone 5/6.  I left it run for an hour longer than usual, but the cone was not bending.  I realized that the gas had dropped off.  After fixing the issue, I went back inside. It was now 3 am Christmas morning, and I had an alarm set to go off every 15 minutes, but instead it went off after another 45 minutes.  While I nodded off with”visions of sugar plums dancing in my head” the little Amaco AG40 was over firing.

I jolted awake and looked at the time and realized the problem, then rushed to the kiln and looked through the peephole.  The bottom shelf was running real hot, and the middle shelf cone was now all the way down.  Thinking I caught it in time I started the 2-hour cooling cycle the manual recommended. All was fine until I opened the kiln about 30 hours later.

The bottom shelf was severely warped with cone 5/6 clay pots melted to it. It appeared that the shelf might have gone to cone 9 or 10.  The second shelf of pots had blister marks in them, so I suspect this shelf reached cone 7/8.  The top shelf was perfect.  I was able the salvage five good shave bowls to give to friends.

All of this was great practice on how quickly things can escalate even if minor adjustments are made.  I am still working out temperature differences, and the little Amaco AG40 needs new bricks and repair work done.  But the kiln has grown on me, and I enjoy firing it out in both reduction and oxidation firings.

Click here for the manual for those who may need it. It’s quite old but had some good information in it.  If you would like to add your experiences or tips concerning the Amaco AG40 or updraft kilns in general, feel free to comment!

 

20160512_185726
Al Wayman
Artist /Owner
Creek Road Pottery LLC

/0 Comments/by

Welcome to Creek Road Pottery!

, , ,

Welcome to Creek Road Pottery!

083544

 

We are happy that everyone has stopped by for a visit and we have been working on the website to get it ready for for future content.  We would like to thank everyone who took part in the pilot order program.  It was a big help as we find our areas of strengths and opportunities. It was always my dream to open a ceramic pottery and work clay.  Running an operation is hard work and keeping track of everything has been both fun and challenging. I have a full time job so the pottery is a part-time endeavor for now.

Currently I am working many areas of the business at once. Making the pots is only about thirty percent, the rest is learning to market yourself to customer segments that you would like to target. There are many areas we need to improve in.  One area is to add more glaze colors to the pallet I have.  When I started out running tests and composing a glaze I at first wanted to keep it simple so it would cut down on cost to the final prototype when it came to raw materials.  I was able to find a recipe with only four ingredients. However, this had to be modified to the clay body I was using.  The clay body had large amounts of Iron in it that would come out during the firings and interact with the oxides in the glaze.

Also there was, and still is, the issue of to much reduction in the kiln, causing both the clay and glaze body to go much darker then planned.  In the future I plan on allowing more space and air flow through the kiln to allow the glaze to oxidize and this should bring about the nice blue/green colors I am trying to achieve. Once I am able to get a few more of these challenges worked out the color should be more stable and add value to the ceramic ware.

A huge help was having small electric kilns that could be turned into gas updraft kilns by purchasing a simple kit (shown below).  This allowed me to have two kilns that can fire off twenty pound propane tanks with little effort. With the lower gas prices I am able to get two firings off one tank. The kits were easy to use and by cutting a simple hole in the center of both the top and bottom of the kilns and the process of firing was simplified.

 

Another big cost savings that happened quite by accident was the small gas kiln that I had in storage is built in sections.  This allowed me to run smaller loads of orders without using extra gas or waiting to fill a large kiln load like some of the larger potteries. I was able to simply take a ring or two off, place the lid on and fire one or two orders at a time. This add value to the customer experience because it cuts down on wait time, which I found when researching, can take up to 6 weeks for an order to arrive from a larger pottery.  My goal is to get custom orders down between two  or three weeks.

In the next few weeks we will be trying to mail out new orders and also researching how to improve packing and shipping.  Shipping charges currently are quite high due to the weight of the pots and extra packing material that is needed to ensure safe delivery.  We will be looking at some packing techniques used by others in the trade and also be researching some ideas that can simplify the whole process but still manage a high degree of quality. Currently the cold weather has delayed some firings.  With the sub freezing temperatures it was a worry that the small kilns would cool much to fast and cause cracks and crazing.

Stay tuned to win free pots as we do more prototype testing to find out what is important to people and what they like. Craftsmanship, Quality, and Customer Service are the big three items we are working on. We appreciate any feed back or ideas you may have.

Once again we thanks everyone for stopping by. I have a long way to go but am having a blast working with you all.  The guys have been upbeat about getting their pictures on the website.  There are even links to their Facebook pages so you can learn more about the team.  Once we get all the administrative things out of the way and streamline the process things should get mush easier. Once again thanks for all your support!  Be sure to leave a comment below and say hello!

 

– Al Wayman,

Creek Road Pottery

 

/5 Comments/by