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!