Outdoor Kilns And The Elements--Opinions?

[TortoiseAvenger]

Hello. I'm considering building this:

 

(Scroll down to the bottom for the more permanent brick model)

 

http://www.corvusmoon.com/index.php?option=com_content&view=article&id=47&Itemid=53

 

Do you think I can just leave this out in the rain? I assume I'll pull out the pyrometer after each firing. What happens when it rains during a fire?

 

I can always cover it with a plastic tarp when I'm finished, but obviously this has to be done when the kiln is cold.

 

Any tips, suggestions, or opinions? Has anyone else built something similar?

[Mark C.]

Welcome to the board

No you cannot leave this out in the rain

The bricks and fiber will soak up the water and not work well wet.

You will need to cover it .Think like a turtle  which need a shell to keep bad things out. I would avoid firing in the rain as well.

You could build a roof over it or a small shed-the tarp will work in a dry climate

(I do not know where on planet you reside?)

The drawback to this design is you need to reach down inside to get the pots.

Consider a wire basket counter wieght design to ease reaching work or a front loader design.

Mark

[neilestrick]

Do not let it get wet. The fiber will fall apart. And if you fire those bricks when wet, as fast as a raku kiln heats up who knows what they'll do. Possible cracking and/or explosions there! You could do something as simple as a piece of sheet metal over it, and a tarp when it's cool, but a shed structure would be ideal.

 

Reaching down into that to pull the pots will not be fun. Any type of raku kiln where you pull the lid or pull the entire body of the kiln off the pedestal has some major safety issues in my opinion. Working with fiber blanket has major safety issues, too. Consider building a soft brick front loading kiln if you have the means to do so. Mine is a small updraft kiln with a welded frame and hinged door. You can see photos HERE. Unloading is super safe, and because the door only has to be cracked a bit, the pots stay hot during pulling.

[Benzine]

I used the same website, as one of my guides, when I was building my Raku kiln.  Mine is more like the top version, on that page, only mine is not a top hat version.  

 

I have never had an issue, with reaching into my Raku kiln.  I take the proper precautions (thick gloves, long, non-synthetic sleeves, eye/ face protection) and of course the tongs are the only things reaching inside the hot kiln.  

 

I will add, that if you build the kiln, make sure your ports are big enough.  I made mine just a bit too small, and really affected the max temperature I could reach.  Made a quick adjustment to each port, and it made a world of difference.  Not only could I reach a higher temperature, but I could do it faster.

 

Also, Neil makes a good point about the fiber blanket.  It can be nasty stuff, if you don't take the proper precautions.  Wear a breathing mask, eye protection, hand protection and long sleeves.  It's like fiberglass on steroids; both in terms of how well it insulates and resists heat, and how abrasive it is.

[Marcia Selsor]

I had this kiln outside in Montana for 5 years, but covered with a tarp.It stayed dry.

http://community.ceramicartsdaily.org/gallery/image/2221-rakukilnframejpg/

 

Down here in South Texas tropics, I built a kiln shed 10 x 20 for electric kilns and raku kilns.

I have more rust on the inside kilns most of which were new after I relocated.

http://community.ceramicartsdaily.org/gallery/image/1440-my-raku-kiln-from-discussion-dec-22-2011/

Marcia

[Mark C.]

Marcia-the links did not work.

Mark

[Tyler Miller]

I fire outside and bring my kiln inside--small updraft gas kiln.  Where I'm located for most the the year, the humidity is so bad that if I leave the kiln out over night to cool and then fire it again right after unpacking, I'm driving off moisture from kiln and frame pretty bad.  This has contributed to accelerated kiln wear and tear for sure.  The fluctuations in ambient outdoor humidity, separate from precipitation problems) can have a real effect on kiln longevity.

 

With regard to Neil's coments on insulating ceramic fiber, something I've often wondered about is why potters/ceramic artists don't seal the fiber with a mortar like satanite or a castable refractory.  It's standard practice in the blacksmithing world in order to flux-proof a forge and make it a little more safe, but it also seems to reflect the heat to a greater degree than ICF alone.  Perhaps it's been tried and there are obvious reasons to why it's not ideal, but it's something I've wondered about trying myself.

[Guest JBaymore]

Using fiber is not simply about the "annoying" factor of RCF (Refractory Ceramic Fiber).... it is classified as a suspect human carcinogen (USA) or human carcinogen (EU) .... man-made asbestos, if you will.

 

I cringe watching that guy leaning down with his breathing zone into that brick enclosure with the dry fiber with no mask on. (A little knowledge is a dangerous thing. We are back to "VET your souces!" ) Make sure you are using a HEPA (or P-100) filter resprator ... and that it FITS (to legal standards).

 

Here's a quote from the US CDC:

 

"With increasing production of RCFs, concerns about exposures to airborne fibers prompted animal inhalation studies that have indicated an increased incidence of mesotheliomas in hamsters and lung cancer in rats following exposure to RCFs. Studies of workers who manufacture RCFs have shown a positive association between increased exposure to RCFs and the development of pleural plaques, skin and eye irritation, and respiratory symptoms and conditions (including dyspnea, wheezing, and chronic cough). In addition, current and former RCF production workers have shown decrements in pulmonary function."

 

 

Here's a quote from the European regulatory agency that is similar to the NIH / OSHA:

 

"3 The main concerns are in relation to potentially serious long-term health effects; experiments in animals have shown that RCFs can produce lung fibrosis, lung cancer, and also mesothelioma (a rare tumour of the lining of the chest cavity usually only associated with exposure to asbestos) following long-term inhalation."

 

Also see here:

 

http://ntp.niehs.nih.gov/ntp/roc/twelfth/profiles/CeramicFibers.pdf

 

 

 

As a pro kiln builder I ONLY work with it totallty wet. And only use it when there are few other decent design options. (A single wetting of fiber blanket is OK). But that is tough to work with wet..... hard to not rip the blanket and it gets heavy.

 

best,

 

..........................john

[Mark C.]

I think you could spray the outside of showing fiber with a thin sodium silicate spray to seal the fibers from floating around??

I have sprayed it with my zircon and colloidal silica on the hot face a fair amount-you just need to keep all coating very thin.

Mark

[Guest JBaymore]

Marc,

 

They make a product called "ceramic fiber coating cement"........ it is colloidal silica with ball milled ceramic fiber added.  Seals the surface from dusting.

 

best,

 

..................john

[Mark C.]

Thanks  John I googled it -it was a name I knew  back in old memory-rigidizer

http://skylinecomponents.com/In-Stock_adhesive.html

Hows this work say on outer fiber surfaces that get zero heat?

Mark

[Guest JBaymore]

I've used it on a few layers of 1" blanket that I've layed over a 4 1/2" arch layer of IFB.  The coating air hardens to something about the consistency of a heavy ice storm on top of a base of snow.  Solid, and no dusting, but it you hit it heard enough, you can crack the outer layer.  But if not in places that will take abuse...... works great as a "solution' to keeping finer dust out of the air.

 

I've also used Greenpatch 241 as a coating on the outside of such fiber layers.  That works great too.

 

One is white ... one is about black....... pick your color scheme.

 

best,

 

.................john