Rogue Train Kiln Firing Plan

 

Preparation before firing

Have two bays of wood split for side stoking, one bay of wood split relatively small for feeding the bottom door for the start, and other bays with wood for the top door that is about 20″ long up to 7″ in diameter.

Arrange the shifts to have just a couple people for the first half, then 4-5 people for the later shifts where it gets busier because of side stoking. Sealing up the kiln at the end is a massive job, good to have 5 people for that if possible.

When loading, label cones and make sure they are visible. Have a recording sheet for them. Be protective of the pieces along the stoke alley. Have three ranks in front, two in back and leave the rest of the space for the alley. Wadding on the posts dries out quickly, so put it on both sides of the posts and immediately put the shelf on top. Load some oak in the firing alley so it can smolder and ignite as the fire builds.

Fire up the generator and splitter to make sure they’re working if needed. Fill them with gas.

Candling

Air: Two bottom ports open
Damper: Open
Temp range: 0-180F

Use the propane burner fed through a bottom air port to candle overnight. It won’t get over 200F but that’s fine.

Starting bottom fire

Air: Two bottom ports open
Damper: Open
Temp range: 00-1000F

Start a small fire in the bottom by placing some kindling on top of the propane burner. Feed with smaller wood, shut down and remove propane burner when the fire is self-sustaining. Aim for 100F/hr rise.

As the temperature increases, it gets harder to fit more wood in the bottom. Try shifting the coals around by poking through the air holes and the door. It that isn’t helping, start the process of shifting to the grate earlier than 1000F.

If the temperature won’t rise:

  1. Rake the coals and push them toward the back too.
  2. Try putting in smaller softer wood (pine or fir) which will burn faster.
  3. Possibly open another lower air port hole to get heat from the embers.

Preparing to shift to grate

Air: Two bottom ports open
Damper: Open
Temp range: ~1000F

Open the top middle air hole for at least 15 minutes to help heat up the top of the Bourry box before putting wood on the grate.

Shifting to grate

Air: Two bottom ports & top middle port open
Damper: Open
Temp range: 1000F

Put one medium piece of fir on the grate. If it doesn’t burn immediately, then wait another half hour and try again while continuing to feed the bottom. For the next hour you’ll be feeding both the top and bottom as you transition.

Getting for body reduction

Air: Two bottom ports & top middle port open
Damper: Open
Temp range: 1000-1582 (Cone 012)F

At this stage, a total of 3 open air holes should be plenty. Two top holes are good for circulation, a lower hole is useful to have open so that you can poke rebar in to redistribute the logs.

When feeding the top, place fir logs in a layer across the grate and then larger fir and oak logs on top. We don’t want newly added logs to fall through the grate. Be careful to never let coal bed build up enough to block the throat. If the throat is blocked by coals, ream and open lower air holes to lower the coal bed so that it’s no longer blocking the throat.

Every half hour ream the coal beds to redistribute the coals. Work from the top holes down.

If the temperature rise stalls, check the following:

  1. Check chimney airflow, you should be able to see through the screen. If smoke is coming out of everywhere the chimney may be blocked or the dampers are in too far
  2. Check the coal bed, rake charcoal out.
  3. Feeding pattern: try fir for a while, smaller wood too.
  4. Shift the wood around to let embers fall through the grate.
  5. Check the air holes, try different patterns.
  6. Maybe start using the stoke alley.
  7. Possibly open the dampers if it is in too much reduction.

Body reduction

Air: Two bottom ports & top middle port open
Damper: Closed to 40%?
Temp range: Cone 012 (1582F) – Cone 05 (1888F)

When ^012 (1582F) in front goes down, go into body reduction by restricting the air intake and closing the damper. This will stall the temperature rise and produce smoke. We do need it to keep rising until ^05 (1888F) is down everywere, so allow enough air flow for that. It may be necessary to side stoke to help this happen.

Finishing body reduction to cone 8

Air: Two bottom ports & top middle port open, more as needed
Damper: Closed to 40%?
Temp range: Cone 05 (1888F) – Cone 8 ()

If you haven’t started side stoking yet, then when the front hits 1900F, start side stoking to even out temperature front to back. Gently add kindling through the side stoking ports by hand or with a push stick. Side stoke first, then feed Bourry Box.

Cone 8 down, getting to cone 10

Air: Two bottom ports & top middle port open, more as needed
Damper: Closed to 40%?
Temp range: Cone 8 (1888F) – Cone 10

When cone 8 goes down and 9 is 1/2 way down, note that temperature. The goal is to stay at that temperature and below until the end of the firing. Feeding wood will drop the temperature. When the temperature rises to the target, feed again. Cone 10 should go down during this process. Continue to side stoke as needed.

After ^10 is down in front, keep going through the end of the schedule to let the ash melt on the pots. Feed the back more than you feed the front. Don’t take it any higher. Concentrate on evening out the kiln temperature.

Shutting down

Air: Everything closed and sealed
Damper: Closed
Temp range: Cone 11 and down

Once cone 11 is down, do a big stoke and put the dampers in half way to let them warm up. Plug everything, open the passive damper, put the bricks in the doorways and seal up all cracks with wadding. Then push the dampers all the way in and seal their bottom edge.

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