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Question 1:

 

Hello,

Sasha from Serbia is here.
I want to build a kiln for firing tiles . I haw very little knowledge in the pottery field, only that I have found on the internet.  My current problem is to build a kiln for my tiles.  I didn't see, what's the price for the catenary arch kiln book?  Is it a gas fired kiln?
I will use propane for my kiln .What are the dimension of the finished kiln, how much and what kind of material do I need for the kiln, since I only have firebricks available here.

Regards,
Sasha

Answer 1: Sasha- 

 CATERINA CATENARY is the gas fired kiln you want to have!  It is the easiest and most successful kiln to give you good results with your tiles for many years !   The cost of the eManual on how to build CAT is US$26.00 when purchased online.  This eManual provides diagrams and all information you need including the proper information for firing with propane gas, how many bricks are needed and other necessary items.


 Question 2:

 

Just reading, reading and re-reading Rocky's instructions. I see where adhesive is called for, but don't see it's use in the directions.  I don't want to presume to know where it's application lies, so rather than blow things up, I thought I'd ask.

Also. when you say small hand held vac, are you referring to a dust-buster type vac?  I've never owned one, so I'm not sure it has the right type of exhaust end you refer to.

 

Answer 2:

Sorry for the delayed answer!  With making ROCKY, it is not really necessary to use a hi-temp adhesive ,although I know it is there in the materials check list.  I used  to glue the fiber lining inside the lid of ROCKY, but have gotten away from that and now simply wire it in place with a length of nichrome wire.  Even so, most major ceramic supply houses DO carry a ceramic adhesive of one sort or another.  I.e.: www.axnerceramics.com .  Also, I might mention that it really comes in handy for maintenance to fill in expansion cracks in the refractory floor of ROCKY after many uses.

As for a "hand vac", I encourage you to use anything you can get your hands on that will push a moderate blow on the exhaust end.  Stay cheap with this!  Last year I found an old used "Dirt Devil" (red, yet!) in a swap shop which I paid 8 bucks for.  I whacked off the cloth end of the dust collection bag, crimped it around a short length of flexible hose, like a vac hose, and Duck
taped it!  That baby works like a charm, bringing my ROCKY up to 1600 degrees F. in 30 sec's.  Used it about 100 times already!  But, anything that blows reasonable well, will do, just don't use your mother-in-law no matter how hard she blows!


Question 3:

 

I just downloaded your drawing for the self generating oil burner and I
found it very interesting.  However I would like to have some more details on the operation of this unit.
1- Can I use Waste Vegetable oil and used motor oil in this unit ?
2- The path that follows the fuel line is not clear to me could you explain some more.
3- Is the fuel coming out from the orifice plug ? If yes what is the hole diameter ?
4- How efficient is the burning on this unit ?

 

Answer 3: Any type of fuel which must be heated to vaporize;  i.e.:. crankcase
oil, cooking oil, diesel, motor oil, etc. can be used in this burner.  You notice that the source oil is gravity fed below the burner casing.  When a small flame is made in the metal trough
under the burner casing, the oil will  vaporize and  create pressure inside the double lined cylinder cavity, forcing combustible gas out of the orifice plug which points inward over the back of the burner.  This size of the orifice hole at the end of the plug can vary depending on the type of oil used.  You will have to experiment with different size orifices for best operational efficiency.
Note: the 2nd sentence in the description of the diagram IS misleading.  I will eliminate it!
The effiency of the burner, once operational, is perpetual.

 


Question 4:

 

I am enjoying my ebooks. I love looking at them especially the pictures with instruction. I have some questions I hope you can help me with. When you fire those mexican tiles from home depot, do you know what they were fired too? Can I just put commercial 05-06 maiolica glaze on them and fire them.? I use someone elses kiln and I am afraid to blow it up. Do you just treat them like commercial 04 bisque tiles? On page 3 in the hand painted tiles book, what are the names of those > colors on the palette tile? Are they mason stains? I would love some instruction on painting a picture in one color. When you paint a picture all in Blue for instance, how do you go about it. How do you start out? Do you paint it all light first and then go over it again to darken areas? Do you start out with a bunch of varying strengths of blue? How do you do it? Thank You for any advice and direction you can give me. Thanks Pat Sartor 

 

Answer 4:The Mexican tiles are ready fired pieces. You can think of them as being a low fired bisque, I would guess cone 010 or lower. Because they are pre-fired, however, you can feel safe the "chemical water" is out of them. Then, if you glaze them and put them through a 05/06 glaze fire they are going to go through the bisque cycle on the way up to glaze maturity. There should not be any problems! There are two approaches to applying a colors on a blank tile: 1) use any type of pre-made colored glaze;, i.e. Amaco (www.amaco.com) or Duncan glazes (www.duncanceramics.com) straight from the bottle. The 2nd, is the Majolica approach which is what you may be referring to for getting different shades of the same color. With Majolica, you need to first cover the face of the tile with a clear base, or matt clear, glaze. This becomes your pallet upon which you paint different degrees of colored oxides. You can set up your oxides in little pools on a glass plate, some thin and diluted, and a few strong in intensity. Then, as if you are painting with watercolors, simply paint ontop of your glazed tile(s) as if doing a watercolor painting. This technique is well covered in the eBook "Majolica Tiles".

 


Question 5:

We would like your experience to weigh in on a neighbors concerns about fumes from glaze firings and raku:

To date, we've been using a small electric kiln in the garage (about 10 months). We do NOT use any lead, barium, manganese or other known problem chemicals. Our glazes use primarily copper, cobalt and sometimes silver nitrate as colorants. The reduction process uses newspaper in a trashcan, sometimes with a lid and sometimes upside down into sand to reduce the smoke.

Our neighbor says she gags and cannot breath when we raku, or even just glaze fire. One time she reacted to the wax burning off at around 500-700 F. Certainly there are health concerns with most artistic processes, but even a visit from the EPA came out in our favor of us.

P.S., To give perspective, she also complains about other issues besides the ceramics.

Can you please comment on health and safety, for us and for neighbors?

Larry


Answer: Larry- Seems like your neighbors are overreacting and just want you to shut down because they don't know what you are doing exactly!
You know if you don't know what is going on, it is going to be a negitive response.

When I have have had this happen, my initial reaction is to invite them to come over so that I can show (educate) the person on just how it all happens. In fact, I might show them a finished raku bowl, give it to them, or offer to have them do one themselves that they can keep!
Of course, you are dealing witha complaint of "odor". A strange, unfamilar odor is hard to fight simply because it is an unidentified experience.

Presently, I would try to ":double" cover your drum when going into reduction. Like, get hold of an empty 55 gal. drum and put it over the top of your can which is smothering the vessel being reduced! With SMOKLESS raku, although no organic material is actually being burned , odor
of denatured alcohol occurs. However, a nearby fan can disperse that odor within a foot or 2 of the where the action is taking place


Q :  I need to build a forced air burner for natural gas with 7" water column pressure. The BTUs required will be a max of 620,000. Do you have plans for sale that illustrate this?

Answer: Randy- I believe that "FREDDIE M. FURNACE" has a diagram for the burner you are looking for. In this case BTU input is controlled with your blower damper as the internal gas orfice is more than enough to give you

the BTUs you require. Be sure that your natural gas regulator allows enough volume to go through the gas line. A standard natural gas regulator for domestic use, i;e. gas range, etc. will not do it!


 


Q : I would like to use a thermocouple and pyrometer with my Caterina kiln design and would like your advise on where best to place this. I would be very grateful for some advise on this subject, I tried the contact section on your website but could not get it to work

 

Answer: I would suggest two locations to insert your pyrometer.  One would be into the back of CAT when you are building her.  When you are setting in the brick for the back wall, and before covering with fiber blanket and then lath wire and cement, leave a half brick space opening,  in the middle of the wall so that you can insert the probe.  This would be like having a peep hole in the back CAT.  The other, naturally, is simply to accommodate  a similar opening into the front door where you might otherwise have a peep hole.  In this case, it would be necessary to insert your probe each time you block up the front door to start a firing.
However, with having the front as an alternative to insert the temperature probe, it gives you a means to check heat from two locations

 

 


Q: Can I build Caterina on a metal stand that will move in and out of my garage?

 

Answer: CATERINA CATENARY My own CAT kiln does indeed rest on a metal frame.  Your idea of making your kiln a "roll out" appears to be a logical approach to making it somewhat portable.  I feel that if you are a good welder, or have a professional welder make up the frame for the refractory base to CAT, that it WOULD work for you.  There are two factors which will make this at all possible.  One, when you construct the kiln, be sure that the fitting of all brick are absolute.  That is, that everything fits tight.  Don't use brick mortar.  That will not allow the kiln any flexibility, either for firing or for moving.  The 2nd, is to use no less than quarter inch thick angle and channel iron when welding up the frame.  Be sure to cross brace all sides of the six vertical legs you will attach to the frame.  The channel iron will be used as "ribs" on the bottom of the frame to support brick.

Keep in mind that CAT will expand and contract fractionally, with each firing.  Contraction is always a little less than expansion which means that CAT will get wider and wider over the years.  My own CAT eventually had to be pulled down and rebuilt after about 10 years of usage (mostly to cone 10, yet).

The great thing about a catenary form, which Galileo invented, is that it carries its own downward thrust without external bracing.

 

 


Q: I built  the raku kiln, but am having some difficulty with the propane gas line.  It freezes pretty soon after I light it.  We get ice condensation on the copper tubing and nozzle of the propane tank, and then the gas in the tube seems to freeze.  Can you tell me what I am doing wrong? 

Answer: Freezing of a propane tank occurs easily when the fuel capacity is really low!  If you are using a partially filled tank it won't take long before freezing occurs, which in turn will drop output level and diminish the high capacity forced flame you desire.
This can occur irregardless of the size of the tank. Additionally,  freezing will be accelerated if you are at high altitudes or simply have really cold outside environmental conditions.

One way you can "nurse" a freezing tank is to pour water over the tank during the operational phase.  If you place hot water soaked rags or towel could do the job too!  As you are using the fuel, keep feeling the outside surface of the tank to determined at what level the tank is starting to freeze, allowing you to start the defrosting application to keep the action going!  Of course, the obvious answer at this stage is simply to get the tank "topped off" , or switch tanks.  Always helps to have a back up tank

 


Q: I bought your plans for Rocky Raku and am very close to finishing assembly. I have a few questions:

1. You have high temp cement on your materials list, but I can't find any mention of it in the instructions. I could not find the cement, but did find sodium silicate. What do I do with it? I can't find any instructions about gluing anything. My pottery supplier could not give me any clue how to use sodium silicate as a glue.

2. You mention that the real "key" is how much preheating goes into the vessels before you put them in Rocky, but there are no details about how this would be done or how hot they should be. Is there another device (kiln) needed to preheat the pots first? That would kind of defeats the portability aspect of the kiln, but I'm sure I'm missing something.

Answer: Sodium silicate is simply a substitute for "colloidal silica". In either case it is used to glue tabs of the fiber blanket into place during construction. Or, can be sprayed on the blanket surface to "rigidize" it for a little better durability during usage.

When firing raku, your piece needs to be without moisture in the clay body. You can "pre-heat" it in an oven, at a campfire or use the suggestion stated on page 7, last paragraph, of ROCKY eBook.


Q : I can't get sufficient pressure to give Rocky a heat rise. We included rocky in our annual pioneer farm festival and he was sure a hit. As I assembled everything a couple of days earlier, everything went together nicely.  When I went to fire up, I could get very little heat. I tried changing air/gas settings to no avail.  Not enough gas! I removed the regulator; still not enough gas!  I took the tank connector (adapted from a grill replacement connector and regulator) and noticed that the orifice was very small, and (probably breaking every rule) drilled it out a bit larger.  Hooked it back up....Viola! Hooked the pressure regulator back inline, still worked fine.  Just wanted to share that info with you.

The kiln worked great and we were thrilled with the results! Thanks you for your design!

Answer: Michael-  Thanks so much for sharing your experience  with  ROCKY and his orifice hang-up.  I am going to put your comments into our FAQ's section.  With the change in tank regulators everywhere, it takes a little innovating
to get that pressure out!  Because of this, I recently purchased a new 20lb. tank and found, at the local hdw'r store, an adaptor (Propane Fitting #F273757-"Mr.Heater") which allowed me to bypass the regulator and go direct.  Even so, I noticed that the orifice was really very small.  I was about to drill it out but made a test first, and found that I had sufficient pressure to fire up to 1500 F in 30 seconds. So, you did the right thing!  Smart man!

Thanks again!


Q : Several months ago I ordered your Rocky Raku kiln plans and I am just now getting around to acquiring the material to build my kiln.  I have come across a cache of small squirrel cage blowers that put out about 100 CFM of air volume.  The price is right, $20, but my question is, will this volume of air output be sufficient to power Rocky's burner?  Is there an optimum air volume for the the blower that is required for Rocky's burner.

Answer: The volume of air input to the heat chamber is totally predicatedupon the fuel/air ratio.  In the case of ROCKY, because the heat chamber is relatively small, it can operate at a rather low air input (squirrel cage) so long as proper combustion is occurring; i.e.; a mixture of fuel and air to create a steady blue core flame.  However, it may take some time to reach glaze melt temp. Any old used vac tends to have more "forced air" than squirrel cage blowers.  I just picked up a
small hand vac at a local 2nd hand store for $12.00.  It is all plastic with
a fabric collection bag.  I simply cut off the end of the collection bag
and, using duct tape, crimped around a 1 1/2" O.D. flexible tube (vac tube). Stuck this contraption into my ROCKY kiln and got to 1500 degrees F in less than 2 minuets.  This is using propane.  Natural gas will take longer.

 


Q : I enjoy this web site so much ... and I want to buy the book which has the material in it to make the rocky raku .. I want to ask you some questions....
  1- Is the material of making such stuff available in any place in the world or not? ...
  2-  this rocky raku .. are there different sizes .. and how much will it cost...?
  3- if it is possible to buy one .. in cash .. from where can I get it.?
  4- what is the cost of the rocky raku book?
 
If all of this is available please write to me the cost + the price of charging it to Egypt...try to contact me soon .. I wait for your reply... thanks a lot for your time .. and I hope you're enjoying your time      

Answer: Here are the answers to your questions.

First, yes, you should be able to get the materials you need for ROCKY anywhere.  I provide you with internet addresses for many of the materials.  This will allow a supplier to ship you materials if they are not available in your local area.

ROCKY RAKU is a portable raku kiln which you learn to make by following the instructions in the ROCKY eManual that is sent to you as an attachment to the email order you place.  There are no ROCKY kilns already made and for retail sale.  All such kilns are made by individuals who followed directions in the eManual they receive online.

The size of ROCKY is the size of any small metal container, which has a lid.  Like the size a 5 to 10 gallon container. You will meet ROCKY as a cartoon which will give you a view of the container.

The cost of ROCKY RAKU is $US 18.00 when you order it directly at www.R2D2u.com .  When you order, subscribe to PayPal
(instructions included) which allows you to buy electronically.  Even better, you can save money by getting the RAKU COMBO:
This is 4 eManuals.  One on how to make raku tongs, making raku tiles, smokeless raku, and ROCKY $US 38.00.

 

 


Q : I am getting ready to assemble Rocky Raku from the plans I got from you in April 2003.  It looks in the photo that the can used might be larger than 10 gallon.  Will the setup work for a larger can? Have you modified the plans any in the last year?    

Answer: I have just finished making a new ROCKY, using a 10 gal. galvanized trash can.  Tested it today!  Reached 1500 F. in 30 sec's.  You may use a larger container if you wish, just remember that the fuel/air ratio may need to be goosed a bit if you want the same results.  It's all variable, of course!

I have not added anything new to the ROCKY eManual as of yet.  However, I am getting some inquiries regarding the portable fuel tank valve being different in most parts of the country than the old style which was easy to put a  high pressure regulator onto.  I just bought a new 20 lb. tank specifically to address this situation.  I also purchased a standard adapter fitting and eliminated the regulator altogether. As a result I am
controlling the fuel output directly from the tank valve.  Works fine!  I've
taken images and expect to incorporate these into an addition in the ROCKY eManual soon!

 

 


Q : I went to our nearest clay supply place and the ceramic fiber blanket they had was 1" thick and #8 density. The instructions call for 1/2 " thick and #6 density.  In this case is MORE not better? Would that difference make a difference?    

Answer: Yes, it will work fine, more durable and heat retaining.  You are simply paying more per sq.ft. than 1/2" thick.  You can also buy half as much as you need and very cleverly and carefully split the blanket in half to 1/2"  thickness as the plans call for. Place the "split" side against the inside wall of Rocky, and the good (outside) as your heat face inside Rocky's chamber where your magnificent raku piece will be given birth!

 

 


Q: I am going to build a downdraft kiln using power burners this spring (about 20 to 30 cu ft) and thought I'd give you a shout and see what you have to offer for advice...  

Answer: My Roman Arch kiln comes pretty close to the kiln you are describing to build!  However, I strongly advise you to turn your brick around using only a 4 1/2" thick wall and then throw a 1/2" blanket over the kiln.  It will give you better heat insulation and save you $'s!

 If you insist on using "power" burners - I presume you mean "forced air" burners- then you can attach "squirrel cage" air units to the burners I have designed for the Roman Arch kiln.  Caution, however!  Forced air burners will make heat rise extremely fast unless you know how to control the air input.  Venturi burners are smarter, because they create
a natural draft within the burner which is a means of partial air velocity.


Q : Do any of your kilns work for drying wood? 

Answer: Any kiln, except the raku kiln, can be used for drying wood. It is only a matter of how you baffle the incoming flames from the burners and control the fuel input. Long duration flames from propane fuel, for example, will carbonize heavily, clogging up burner ports.




Q : Can you help me build a salt kiln? I am looking to build around a 10 cubic foot kiln unfortunately or fortunately as cheap as possible, used hard brick and building my own burner. I am looking at running a gas line but because of costs, probably have to use propane.  

Answer: The best I can offer you is the possibility of plans for building a 20 cu.ft. Roman Arch hi-fire kiln.  I built this kiln specifically for salt firing some years past.  It worked great!  

 
If you wish I might consider doing a print out of these plans from my
book..  The plans are quite complete but are not tailored for R2D2u yet.  You would have to look at the materials list to see what your costs would be in today's $'s.  It includes all instructions for making burners to operate on either natural gas or propane.
 
Of course, you ARE aware that the vapor from a salt kiln is chlorine gas which is quite deadly. It will kill surrounding trees and plant growth very quickly, if it doesn't kill you first!  When I operated my salt kiln, in less than a month nearby trees were killed.  Since then I stopped using the kiln.


Q : I bought and read your plans, and wondered why you suggest cutting your own bricks versus buying arch bricks?

Answer: CATERINA's arch brick are all  customized  angles  which change from row to row. as the curve of the catenary narrows upward to the keystone brick (see page 9 of manual).  Most standard arch brick available on the market are usually a set angle. Of course, commercial arch brick can be modified to fit the curvature of the arch.  Extra charges for buying arch brick does not make for building a kiln economically, however!


Q :Is it possible to use a venturi type burner system on this raku kiln?   

Answer: ROCKY performs best with "forced" air burner to get a quick heat rise to temp in seconds.  Then , shut down, and restart for next firing!  A venturi burner creates its own draft velocity which will make heat rise in due time.  ROCKY's heat chamber is too confining for a venturi system which could also result in excessive carbonization during operation.




Q : The fact that such a great amount of heat introduced to a vessel in such a short amount of time worries my professors and I that the pottery will explode?  

Answer: Your professors don't understand "fire".  Explosions occur only when fire is in a confined space and cannot get out.  When you light a match, does it explode?  No!  Why?  Because the flame on the match is in an open environment, not confined.  When you light up ROCKY, you have the forced air going and there is no way that you are going to get combustion until you make the proper air/fuel ratio described in ROCKY'S eManual.  You put the forced air on first, not after turning on the fuel!  If you want to play it extra safe, just leave the lid off and where is any kind of flame going to go?  right up into the air!  Remember that forced air is the same as an open environment, plus 100 or more!

 

Q : I was searching the net and found your info on  "Rocky Raku" and would like to know more about cost and materials I'd need.  

Answer: The cost to build the Rocky kiln will vary on what materials you already have on hand. Ours was built for under $50, and we've never heard anyone say the price go over $80. 

For example, the burner operates on a forced air burner system that is made from a small vacuum. If you had to buy a vacuum for this project, that would drive the cost up considerably.

 
Any small portable LPG tank will work so long as there is a high pressure regulator attached



Q : The Diagram in the Rocky eManual says that I need a 4" diameter pipe for the burner, but the text says that I need a 2" pipe? 

Answer: The Diagram in the eBook is incorrect.  The pipe should be 2" diameter not 4" diameter.  Sorry about the confusion, we will make the necessary corrections.


Q : Do I have to fire my  piece in a regular kiln before I can fire it in Rocky?    

Answer: Rocky can act as a pre-heater to bisque-fire your piece. I would recommend an almost sagger-fire approach, enclosing your ware inside brick inside the kiln, and then monitor a very slow flame for 3-4 hrs. As the Rocky manual as-is calls for a rapid-fire blower system to deliver high amounts of flame energy in a short period of time, you may consider replacing the blower called for in the manual with a something more gentle, like a hair dryer.


Q :
1) I will have to use propane, since I am in a neighborhood that doesn't have natural gas so, can you tell me how much propane I will probably be using to fire the kiln to Cone 10 temperatures, and an Idea of the firing time is takes to get there? This would give me an idea on the propane costs for firing, the size of propane tank I would need to rent and so on??? .......Is it even cost effective or feasible to use propane to fire the CATERINA CATENARY kiln?

2) Does the CATERINA CATENARY give good results for reduction firing?

3) What are the costs of building the CATERINA CATENARY kiln? $200, $300 $400... (Just a guess?)

4) Can I get a discount if I purchase the "Raku Combo" and the CATERINA CATENARY plans together?

Answer: Thx. for your inquiry about CAT. Let me first suggest that you ck. the FAQ's listed at www.R2D2u.com.  I believe that some of your ?'s are answered.  I'll also include answers I will address for you into that FAQ's for others in the future.

CAT is designed to operate on natural gas or propane.  The CAT eManual provides full instruction for the proper orifice size for the 4 burners along with notations on "how" to fire an updraft kiln for full effectiveness consistently to cone 10 or higher if desired.  The size of propane tank and amount of consumption of fuel is all related to what costs are in your area and HOW you fire the kiln.  If you are planning to fire a lot, I would suggest that you install a 500 lb or larger tank, minimum.  It would be foolish to use a smaller tank which you will need to refill often.

Two important factors relate to CAT being the best solution for your needs.  One, is that you will need only half as many brick as a comparable 12 cu.fl. kiln normally built (see instructions in eManual), and two, how you learn to fire CAT.  All the guide lines are included in her instructions.  Reduction reds is a natural with CAt.  But, again, you need to follow the guidelines in the eBook for getting these conditions.

Again , CAT is the best "cost effective" operational kiln of its kind provided you learn to understand her.  The more you two work together, the better she will perform.  My CAT kiln has been consistently providing me with new birth pots for more than 35 yrs.



 Q: I purchased your plans (Caterina Catenary) and have built the kiln and fired it 8 times (4 glaze firings).  I did not however use your burner design.  I wanted to have more control over the combustion air than your design allows.  I also wanted to use high pressure (30 psi max.) propane.  I built very efficient and controllable burners using the design found in the book "Gas Burners for Forges, Furnaces & Kilns" by Michael Porter.  Each burner can deliver up to 75,000 BTU/hr.  I can reach cone 10 in 9 hours and can maintain a strong reduction atmosphere from 900 degrees C till cone 10 is down.

  My problem is very uneven heating.  On the bottom shelf cone 11 is touching the shelf.  On the middle shelf cone 10 is touching the kiln shelf, on the top shelf, cone 9 is just starting to bend.  My bottom shelf outside dimensions are 20" by 32" so I have a 3" space on all 4 sides between the shelf edge and the kiln wall.  This shelf sits on 4" kiln posts.  The second and third shelves are only 13" wide so there is no restriction to upward heat flow.  I tried putting a 4" tall by 4.5" wide IFB blocker in front of two opposed burners to deflect more heat up.  It deflects a lot of the flame back out the burner port but did nothing to improve heat distributon.  The other 2 burners have your recommended 2.5" high half block placed at a 45 degree angle to split the flame.

  I have tried closing the flue dampers almost completely and opening all 4 of my peep holes in the front wall.  This seemed to have no effect on the large temperature differential and eventually the kiln stalled

  Do you have any suggestions.  I am considering several altenatives some way more drastic than others.
    a.. increase the height of the bottom shelf to 6"
    b.. reduce the width of the bottom shelf  to ??
    c.. remove all flame deflectors
    d.. add a 4th kiln shelf above my pots with minimum space between the shelf and the kiln walls to deflect more heat to the pots before it exits out the flue.
    e.. drill 2 new burner ports one on one side right next to the back wall and the other on the other side right next to the front wall.  I would then add a deflector block to direct the flame up.
    f.. scrap my high speed, efficient and controllable burners and replace then with your design.
    g.. rip the whole thing down and build a minnesota flat top.
  Any advice you can give me would be greatly appreciated. 

 

 

Answer:   There is little I can suggest to favorably modify the conditions of your firing cycle with CAT in that you have place a different burner system than illustrated in the manual.  I see, and understand that your present system is a real power house. So, this is as if you were putting SUV tires on a small sport car and wondered why there were irregularities in how it drove although you could
reach designation.

You are on the right track in making flame deflection adjustments with each firing.  A good deal of your heat containment is influenced by how you have stacked your ware (see notes about this in the manual).  Another factor working against you, to some degree, is the use of propane gas, which is heaver than air and can be a beast to pull up in a updraft kiln. It certainly can be done with CAT, but you are going to need to do more firings to learn how to fine tune flame movement and retention.  Think of CAt as being one single "stack" in which the firing chamber itself is the draft.  The nice thing about CAT is that you can view the amount of flame coming out of the flues ontop and trim and adjust, during firing until you get the correct balance. I used to do my CAT firing always at dusk so that I could see the flame and could adjust the dampers to favor the direction of heat inside. By the way, designed CAT in the mid 1960's when I ceramic fiber was first commercially available.  Lastly, my firing cycle to cone 10 with CAT runs 5 to 6 hrs. Also, you are not that far off in your cone drops from top to bottom when most cone 10 glazes do have at least a one cone variance.

 

 



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