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You Can Do It!

By firing manual you can get to know your kiln, better understand the firing process, and even manipulate the work by making changes to the firing schedule. This is good practice especially for beginners learning the firing process and firing techniques. It is my opinion that when firing out work in a kiln you need to be there through the whole process as it’s like giving birth. It is quite simple to do but just takes a bit of monitoring and being able to see the correct cones inside the kiln when it is hot and knowing when to shut the kiln off or start the warm down.

The Sermon

Even though many kilns are digital or use a cone sitter, I am a hardcore manual kiln fire guy. Which means I fire all my kilns , even bisque fire, with shelf cones. Now I will not preach at you like a baptist minister if you choose to fire digital shut off or use a sitter, but in my opinion you are depending on luck to shut down each load. Mistakes like putting in the wrong cone number digitally, wrong hold time, improper sitter set up, improper cone set up in the sitter, or the sitter cone melting in a strange way and not shutting down all can cause a kiln to over fire. I witnessed a kiln melt down when I was a young wart hog and ever since fired manual. Kilns can be like children playing in a sandbox next to the road. For the most part they will be fine but if you forget to check on them in no time flat they will be out playing in traffic. You do not want your kiln to be out playing in traffic. Forgetting your kiln could result in a melt down where all the work shelves and posts become like taffy stuck in there. If you simply do a google search for kiln meltdown you will see some amazing images of things that happened when folks had a bad time with their kilns. You will still have a bad time with your kiln even if monitoring it but those bad times will be less painful and disaster averted by taking corrective action. Amen.

Proper Setup

It depends on what types of shelf cones you have. Cones measure both temperature and work heat. If you use a pyrometer to check your kiln, you will only know temperature. Pyrometers do not measure work heat. Some shelf cones need to be placed in a cone pack while others are self standing. I like to use self standing cones in the peepholes and place them on a small piece of kiln shelf or post. When placing them in the cone pack, be sure to research the recommended angle by the cone manufacture. I set the cone almost to the edge of the shelf, so they are easy to see inside when things heat up, and it all looks the same color. At high temperature, you might be able to make out just a slight outline. Some say not to place it near posts or near elements, but I like it right out in front. Be sure your cone will not attach its self to a pot when it bends, cones like personal space.

Looking in There

When things heat up hotter than a goats butt in a pepper patch it might be hard to see the cone. When you look in there it is best to use welding glasses as you do not want to damage your eyes over the long run. Also, if firing with gas pull the plug and wait a bit as if the kiln is in reduction you may have flames shooting out the peephole. So when you look in there be aware of that flame or you can lose eyebrows or catch your good flannel shirt on fire. Now look in there real slow and find the outline. I try and place the cones in front of a pot to see it better. Another technique is to shine a flashlight in the and have the light reflect off the cone. You can also blow into the hole to slightly cool the cone to see the outline. At times if I was not sure and cold not see it I shut down the kiln to be surer than restarted.

Reading the Cone

Be sure to look at the chart put out by the cone manufacture. Orton has a free chart that you can download here.

Also, be sure to check the cone manufacture bend chart. You can see an example here.

Checking the Kiln

Each kiln is different But here is the schedule I use for both bisque and glaze fire to cone 5/6 when firing manual.

Hour 1 & 2 – Check each hour
Hour 3&4 – Check each 30 min
Hour 5 to Cone Drop – Check every 15 min

Below are some examples and tips on what the cone will look like inside the kiln and suggestions on when you might want to shut it down.

When to Shut It Down

Each kiln is different and the rate of the cone drop will change based on temperature and work heat.

If you have the cone that matches the firing, say a cone 5 shelf cones and you want a cone 5 firing, you want to shut it down at the slight bend.

Below is what a slight bend looks like base off the recommended bend chart of Orton.

If you have the cone that matches the firing, a cone 5 shelf cone, and you want a cone 5.5 firing, you want to shut it down at the half bend.
I go to the half bend for most of my firings. By going to the half bend you can properly bring to temperature shelves that may be running a bit cooler slightly.
A half bend for a cone 5.5 firing will look like this:

If you have cone 5 shelf cones and would like a cone 6 firing, you would do a full cone bend. It will look like this:

If you are all out of cones and only have a cone 5 shelf cones and would like to fire to cone 6.5 you would do a full bend plus 15 min.
It will look like this:

If you missed a check because you fell a sleep or the cows got out you can still tell about how much time you missed as you will have hard full bends and soft full bends. A soft full bend the cone will look like melted chocolate but be blistered and bubbled out but not a puddle. It will look a bit like below. Here I was out of cone 6 but used a cone 5 plus 30 min to reach a cone 7 for a bottom shelf. So I intentionally over fired to bring to temp a cone 7 glaze test on a bottom shelf.

All the checks might seem excessive, but help to catch mistakes early and also allow you to make correction. In my gas kilns I can see if the kiln is heating correctly, if the firing is going to slow or fast based on color. Also, when testing firing techniques or a new shelf configuration, how big or small the load is or doing holds. All the checks paid off and saved loads and prevented over fires. I have over fired, but only from falling a sleep and missing the last 15 min. Thank goodness my wife woke me and I only lost 1 shelf of pots to blistering. You can also check cone that did not bend to get an idea of how much off you were on the under fire. A cone that did not bend but at all might be like glass and have gloss say it was close to reaching temperature for example.

Do you fire digital or manual? Do you have any questions about firing manual? Let me know!

Al Wayman
Artist/ Owner

Creek Road Pottery LLC

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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

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“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.

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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.

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“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

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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.

 

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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!

 

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Al Wayman
Artist /Owner
Creek Road Pottery LLC