Another Kiln Question

[Jonathan Harvey]

Well my kiln is complete and almost fully loaded and now I'm looking for so advice on how to run it. There does not seem to be a lot of info out there or at least detailed info. I've seen write ups where people leave the light on for twelve hours then off for twelve hours but never any actual temperatures and humidity ranges. I've installed a bathroom exhaust fan to a de-humidistat to control the humidity as well as a thermostat to the lights to control the temperature now I just need to know the best method of running it. Here is my plan that I will try on my first attempt I might end up losing around 50 bowls and some platters but I'm going to give it a shot

WEEK 1: Dip each bowl in water so that they are all wet going into the kiln This water will also help keep the humidity high. Leave bowls in kiln with no heat running or exhaust fans running so that all bowls will hopefully reach the same equilibrium.

WEEK 2: Set temperature to 70 degrees and set humidity at 60%

WEEK 3: Set temperature to 80 degrees and leave humidity set at 60%

WEEK 4: Set temperature to 90 degrees and move humidity down to 50%

Not sure if this will work but it's my plan and I'll let you guys know how many bowls survive in a month from now. :-)

[Bernie Weishapl]

Sounds like a plan and a place to start. Will be interested in your results as I am looking at building one.

[Dennis Ford]

I don't have a kiln and live in a different climate, so this may not apply. Your first week would likely grow some mold in my area.

[Bill Bulloch]

I used that 70 - 80 - 90 degree approach myself back in the Winter, and it worked, however I let the Humidity go down to about 30. Then came
Spring, with the outside temp running in the 80s and 90s and humidity close to 100, that approach would not work. So, I put my wood in and ran the fan for two days without the light. At the end of the two days the inside temp was 86 degrees and the Humidity was 92. I opened both my top and bottom vents (I don't have a de-humidifier) and ran at that temp for one week. After the week, I upped the temp to 95 degrees and ran it for one week. Then, upped the temp to 105 degrees and ran that for one week. The Himidity had dropped to around 30.

I'm thinking that the temperture in the kiln is not as important as drying the wood at a slow steady, controlled pace.

You could run a small load to test your approach first.

[Jim Podsedly]

I have been using the fans for a few days, then 80, then 90 then 100 for each a week. the RH dropped to ~20% at the end.

Also, the type of wood you have in the kiln really makes a difference. I tried the above method with rough turned cherry bowls and most of them split to render then useless. the cracks were through the bottom of the bowl.

Finding that cherry requires a slower drying process. i have my kiln loaded with cherry and went a week with fans, two weeks at 70+fans, and i am into my 1st week at 80 degrees. Thinking i will go up to 90 in another week and let them cook there for a while. so far no cracks. the RH started at 75% and it is now around 50%.

[Jonathan Harvey]

Thanks for the posts guys. The area where my kiln is located stays cool so regulating the temperature in not an issue even in the summer time. With the lights off in my kiln the temperature sits around 65 degrees at night and 70 during the day so regulating temp will be easy. The kiln is loaded to the top right now filled with a lot of Norway maple, hard maple, Manitoba maple (box elder) in platter and bowl form. Some items I've covered in Anchorseal, the very large Platter blanks 22"+ as I want to make sure they survive the process.

I think that I am going to run my circulating fan on low for the first week as I think the humidity will be very high in there and I want to keep the air moving.

I'll update this as things progress and also let you know the end result in a month.

Jonathan

[Barry Elder]

You will need to know what the average relative humidity is in your area if you ever expect the pieces to stabilize. Check with your nearest government weather office.

[Bill Bulloch]

You will need to know what the average relative humidity is in your area if you ever expect the pieces to stabilize. Check with your nearest government weather office.


Why would you need to know this? Say the Average RH in my area is 80. Now that I know this, what can I do to stabilize the bowl? Help me understand this?

[Jonathan Harvey]

I'm not sure why I would need to know the relative humidity in my area in order to stabilize my wood. Can you please help me understand?

[Allen Neighbors]

I think the average relative humidity will determine how the piece will react after it is finished...
Not sure if it will determine anything while the wood is in the kiln... but... I'm not too old to learn something. :)
I'm curious too, Barry... can you explain your statement for us???
Thanks...

[brian watts]

have any pic of the kiln?

[Karl Card]

I have asked a couple guys up around paoli indiana about kilns... they just looked at me and said good luck. i am being told that it is an intense learning curve if you want to dry many different types of wood.
I am also being told that even if you have kiln dried wood and are wanting to make something rather large like cabinets etc, a person needs to let the wood sit in there house to acclimate to the humidity in that house so that there will be less warpage or movement of that wood after the item is built.

[Bill Bulloch]

I have asked a couple guys up around paoli indiana about kilns... they just looked at me and said good luck. i am being told that it is an intense learning curve if you want to dry many different types of wood.
I am also being told that even if you have kiln dried wood and are wanting to make something rather large like cabinets etc, a person needs to let the wood sit in there house to acclimate to the humidity in that house so that there will be less warpage or movement of that wood after the item is built.


You have been told right...All woods are not equal; you can find charts on the web that will help you establish schedules for each. The schedule will vary depending on the species, thickness, grade and intended use of the lumber.

That is in large commercial type kilns.....But, we are talking about SMALL BOWL KILNS. Thier intended use is to reduce the drying time of the bowl while reducing the warping and checking as much as possible. It is sort-of-like putting the bowl blank in a paper bag and waiting several months for it to dry. Only with the Kiln you have more control over the atmosphere and can reduce the time reguired to reach the target point to weeks instead of months. There will probably be some warping and checking with both processes. That is why we roughout the bowl blank leaving enough wood so we can turn out the warping and bring it to finished form.

[Thomas Bennett]

Hopefully you already know this but use only continuous duty electrical equipment in your kiln. A friend of mine "engineered " his own small kiln with various household duty parts and burned it up on the second running.

[Jonathan Harvey]

Hopefully you already know this but use only continuous duty electrical equipment in your kiln. A friend of mine "engineered " his own small kiln with various household duty parts and burned it up on the second running.


Yes sir. I'll post pictures next time I get my kiln opened. I have greenhouse products in there so they are meant to do the job that they are doing.....well sort of :-)

the best part is that I never had to do any wiring of the de-humidistat or the thermostat they were all plug and play.

Jonathan

[Ted Jay]

How 'bout trying this...
http://www.cedarcidestore.com/catalog/item/3343694/2900278.htm