IUS Wood Kiln

ALWAYS notify IUS Police prior to lighting the kiln.  Tell them how long you will be firing and when they are likely to see any smoke coming out of the kiln.  Their phone number is 812-941-2400.

Prepping, loading, firing, unloading, and cleaning the wood kiln is all about TEAMWORK.  For a firing to be successful, you must work as a team to get the kiln ready and have a good firing.

Some points worth noting:

  • You must sign up for shifts BEFORE the loading of the kiln.  If you do not help fire, your work will not get into the kiln
  • The loading is a delicate, precise task – it takes time.  Be patient. It is one of the most critical parts of a successful firing because it determines much of the “look” of the finished work.  Sometimes there is work left over that didn’t get in – this is normal. We try to get everyone’s work in the kiln, but sometimes we can’t.  It’s life. 
  • Because of the size of the kiln, often there is just one person inside the kiln loading – help them out by rolling wads, getting pieces, kiln washing, etc.  There are ALWAYS things to do around the wood kiln, so just ask.
  • During your firing shift, pay attend to the kiln.  Wood kilns never respond well to lots of changes quickly, so stay focused and learn to read the signals the kiln gives you.  
  • When on shift, help will anything you can.  If someone is stoking the front of the kiln, help them by opening the stoke door or handing them wood.
  • COMMUNICATE.  When side stoking, you must communicate with each other to maintain a good stoking rhythm.  If you see something that doesn’t look right, communicate that to others on shift. 
  • Always get a good amount of REST in between shifts.  The whole point of having shifts is so that people do not become exhausted, so your job when not on shift is to rest until you are on shift next.  Accidents are much more common when people are tired and not able to concentrate.

Wadding:

Wadding should be made in advance of the loading of the wood kiln, but only by a few days.  If the wadding clay sits too long, it will begin to mold and smell horrible.

Wadding recipe:  (by volume) 
2.5    Fireclay
1.5    Grog
1    Sawdust
1-2 scoops of Alumina Hydrate

Using a large flat mixing tub (like kind used for hand mixing concrete) dry mix the materials with your hands and WEARING YOUR RESPIRATOR!  After you feel it is mix well enough, add water until it is at the consistency of clay. Mix the wadding so that it is a little on the wet side as it often dries out during the loading.  The sawdust often continues to absorb moisture as well, so sometimes it can dry out a little more after you finish mixing it. It should be slightly crumbly, but still stick together enough to easily roll it into a ball or a coil.

Firing Logs:

Spring 2014

Fall 2013


Cone packs for the wood kiln

The cones we usually use in the wood kiln are: 08, 6, 8, 9, 10, 11, 12.  It’s best to have each cone pack the same so you don’t get confused during the firing.  Also, having the cone 12 still standing in the middle and the back when you’re firing gives you something to see when you are trying to locate the cones at the end of the firing when the kiln is really hot. 

Use the wadding clay to make the cone packs – if the wadding clay is too crumbly, just add about half high fire stoneware with the wadding. It helps to make the cones have a slight arc to them so they are more stable during the firing. Remember that things often move around in the loading during a wood fire, so it helps if your cones are sturdy! Always make a small cup of clay at the front of the cone pack for the 08 to melt into.

To check the proper angle to put the cones in, hold one down on the table before you put them into the cone pack – the bottom of the cones are cut so that it will show you the proper angle for them to be in while in the pack.

Cones for the wood kiln

Kiln shelf arrangement

Back stack:

The back row of shelves uses the small silicon carbide shelves (the black shelves). Position them side by side so that the long dimension aligns with the front and back of the kiln. Leave a gap of a few inches between the shelves and while loading, overhang work into this space. Tri-post this section.

Always remember to put the small brick “extensions” to the air intakes for the side stoke holes. They are made with two half soap bricks and whole brick. Also, DON’T FORGET THE CONE PACKS! There is a cone pack peep hole on the right side of this section. You can also put a cone at the very top of the load and check it through the top exit flue hole in the back wall. In the picture below, notice the cone pack at the very top of the kiln.

Proper positioning of the back shelves

Middle stack:

The picture above shows the proper placement of the middle stack of shelves in the wood kiln.  For this section, use the smaller toilet bowl shelves (16”x24”). Leave a slight gap (about an inch or two) between the back of the shelf and the side stoke air extensions.  Tri-post this section. 

REMEMBER to put a cone pack somewhere in the side stoke channel!  It doesn’t matter if it is on the back stack of shelves or the middle, but it needs to be visible when looking through the side stoke channel.

For the front stack of shelves, use the larger 24”x24” toilet bowl shelves.  Because of the large size of these shelves, we usually quad-post this stack of shelves.  Here’s the front stack from the 2nd firing:

Middle stack (in foreground)

Front stack:

For the front stack of shelves, use the larger 24”x24” toilet bowl shelves.  Because of the large size of these shelves, we usually quad-post this stack of shelves.

Don’t forget the cone packs!!  There are peepholes on the side of the kiln.  The cones in the front should not be so low as to get hit with a stick of wood during stoking.  It’s best to put two cones in the front, in case one of them gets knocked over. As you are bricking up the door, make sure the cones are visible through the main stoke hole.  If they are not, add a peephole in the door as you are bricking it up.

Here’s the front stack from the 2nd firing


Bricking up the door:

Bricking up the door always takes longer than you think, so make sure you are rested and your brain is working properly before you start!

As you stack the door bricks, use the hand-held scraper to remove any clay or debris from the previous firing – this will help ensure that your door bricks sit FLAT in the door and don’t wobble as you brick the door up.  If there are too many air spaces in between the bricks, the kiln will draw too much air through the door. If there are bricks in the door that don’t sit flat and level, use a small amount of wadding to level the bricks.

After you finish bricking up the door, dip pieces of newspaper in slip and cover the face of the door.  You don’t need to go around the air holes – that slip will just crack and fall off.

Recipe for door slip:  Fill about half of a five gallon bucket with soft slip from the reclaim bin.  Put 3-4 large scoops of sand into the bucket and mix with the glaze mixer until the slip is smooth.  You will probably have to add some water – you want the slip to be thicker than glaze, but not so thick that it’ll hold its shape in the bucket after you stop the mixer.

When you finish slipping the door, put the red metal rod in place across the top of the door.  DO NOT over tighten the bolts! Just tighten them slightly with your hand – do not use a wrench.  Bolts in that situation that are over tighten can tear off of the rod as the kiln expands during heating.


Proper attire for stoking the wood kiln:

  • Never wear sandals or open toed shoes
  • Never wear synthetic clothing, no fleece or anything that is flammable or meltable 
  • Tie your hair back, tie any loose clothing back
  • Wear proper leather gloves (with sleeves) when you are stoking
  • Do not stand too close to the kiln, even if it is REALLY cold out. 
  • Wear gloves when handling wood – splinters hurt and can get infected, so make sure and take care of your hands!  You’ll need them to make more art for the next firing!

Firing the kiln off:

Try to not rake the coals during the last 2 hours.  Raking the coals kicks up a lot of ash and can sometimes lead to rough pots because the ash doesn’t have time to melt if you shut the kiln down too quickly.  Use small, dry pieces of wood at the end. Always try to end the firing at the highest possible temperature. 

  1. After you have put in your last stoke, begin mudding up the peepholes around the kiln.  Use the same slip and newspaper technique you used to mud the door up
  2. Let the wood in the front of the firebox burn for a bit and “clear” the chamber.  This usually takes about 15 minutes. During this time, you can work on mudding the holes, but always leave a small hole open (at least) in the front of the kiln to allow air in to burn that wood.
  3. Never close the damper before you are done mudding the holes.  As soon as you close the damper, REALLY hot air will push through any opening in the kiln .. this makes it REALLY uncomfortable to mud the holes!
  4. Use gloves when you mud the holes!!
  5. Remove ANY combustible materials from around the kiln.  Stack all extra wood, remove any loose paper, side stoke wood, etc.  Remember, the kiln shed always burns down in the cooling!!
  6. CLEAN the kiln area thoroughly!  I know you’re tired and exhausted, but muster up the strength to clean the area so when people come by in the morning it looks respectable!
  7. Notify any others on the subsequent shifts that they don’t need to come in.  
  8. Always double check that all of the air holes are mudded and the damper is closed!  Don’t assume someone else will double check!
  9. Lock the kiln pad.  If it’s late, look the building.
  10. Drive home CAREFULLY.  Remember, driving while exhausted is just as bad as driving while intoxicated!!

Cleaning the kiln:

When unloading the wood kiln, always leave the ashes from the coal bed in the kiln until the next firing – they are still hot and can ignite the trash cans!

There will be significant amounts of ash dust on the shelves and floor of the kiln, so always wear a dust mask when unloading. Scrape the shelves with the hand scraper to get most of the ash and wads off of the shelves. If there is anything stuck to the shelves that won’t come off with a hand scraper, use the 4 ½” handheld grinder with a masonry grinding wheel to carefully remove it. It is very easy to break kiln shelves, so using a chisel on the shelves should only be in specific circumstances (sometimes to get the wadding off), otherwise, stick to hand scraping and grinding. When you are done cleaning the shelves, kiln wash them. Sometimes you may need 2 coats of kiln wash. Then, when the kiln wash is dry, stack them like this next to the kiln. Make sure and put pieces of wood underneath them so the shelves don’t get wet.

Proper way to store our wood kiln shelves

When unloading the wood kiln, always leave the ashes from the coal bed in the kiln until the next firing – they are still hot and can ignite the trash cans!  

There will be significant amounts of ash dust on the shelves and floor of the kiln, so always wear a dust mask when unloading.  Scrape the shelves with the hand scraper to get most of the ash and wads off of the shelves. If there is anything stuck to the shelves that won’t come off with a hand scraper, use the 4 ½” handheld grinder with a masonry grinding wheel to carefully remove it.  It is very easy to break kiln shelves, so using a chisel on the shelves should only be in specific circumstances (sometimes to get the wadding off), otherwise, stick to hand scraping and grinding. When you are done cleaning the shelves, kiln wash them. Sometimes you may need 2 coats of kiln wash.  Then, when the kiln wash is dry, stack them like this next to the kiln. Make sure and put pieces of wood underneath them so the shelves don’t get wet.


Where to get wood:

Jim the wood guy – we buy wood from him at $55 a rick. His number is 812-7252160

J & J Pallet (for preheat and side stoke wood) – Call Jeff Anderson at 502-379-9484.  He can arrange a pickup time. Then call the IUS Facilities Services and have them go pick it up with a truck and trailer.  You’ll have to cut it when you get it to the kiln, so make sure and leave enough time to cut and stack it.

Remember that you need to have SEASONED wood.  This means wood that has been cut at least 8-12 months ago.  Seasoned wood should have “checks” in the ends of the cut pieces (small drying cracks), the bark should be starting to fall off, and the wood should make a “sharp” sound when it is split.  It’s ALWAYS better to have too much wood than not enough, so make sure you have a contingency plan for extra wood or dryer wood. Split and stack wood in the kiln pad in advance so that it can thoroughly dry out if it is wet.

The kiln needs about 4 ricks per firing.