Congrats on your firing. And thanks for the enthusiastic account which brings back the raku-urge in me. I wouldn´t have dared putting a large plate
into my rakukiln without preheating it though. I´ve had so many explosions that way. Now I usually glaze the night before and also preheat my ware in the electric kiln before taking it outside. I do mostly bird-whistles, smelling and tasting of tar when you blow them.>Reply-To: Clayart
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: 1st RAKU Firing - An account (long)
>Date: Tue, 1 Apr 2003 13:29:47 -0000
>
>Early on a Sunday afternoon I decided that there was no longer
>anything holding me back from attempting Raku. I had the kiln shell,
>made out of hardware cloth and 1" fiber with homemade ceramic buttons
>and nicrome wire keeping the fiber in place.
>
>I had made three pieces out of raku clay from Armadillo Clay and
>Supply in Austin TX. I had inheirited a bucket of clear crackle
>glaze, the contents of which I still have to identify. But being a
>rebel I put the equivalent of .8% copper oxide and .6% of cobalt
>carbonate in it. Who knew what it would do?
>
>I started the base with standard cinder blocks and quickly found that
>I had to use almost 60 lbs of sand to level out the blocks on the
>ground. (There has got to be a less time consuming way of
>leveling!!!) Next came the K-23 bricks, starting from the inside to
>out, I made three levels (each 2.5") with a 5" opening for the burner
>in a 31.5" square. No matter how carefully I placed the brick it
>always seemed that there were spaces left when I finished an entire
>row. Oh, well. This isn't brain surgery!!
>
>I then connected up my varible pressure regulator and MR100 Venturi
>Burner with an orifice for 8psi propane to my 12.5 gallon propane
>tank and sprayed the hose and connectors with water to make sure
>there were no leaks.
>
>I carved a place out of a couple bricks to nestle the venturi burner.
>
>When I was done it wasn't a thing of beauty, but it would be a joy
>for at least a couple hours.
>
>I set my one 16" roudn kiln shelf on top of three bricks, the front
>one acting as a flame splitter, and set my first piece in the
>center. I opened up the primary air shutter all the way and made
>sure the two spyholes and the top vent were open on the fiber shell
>and set the burner going.
>
>15-minutes later: I turned the burner from 1/8 open to 1/6 open
>
> At this point I must say that I was having my doubts. I
>couldn't see the flame since it was so bright outside but I could
>feel the heat. I looked in and there was no indication at all that
>the chamber was getting hot. Could I have done something wrong?
>
>15-minutes later: I turned the burner from 1/6 to 1/4 and moved it
>within 1" of the burner opening. Covered one spyhole.
>
> Well, it was orange in color where the invisible flame was
>striking the flame splitter brick but other than that no difference
>in the kiln chamber. I did feel the heat coming from the vent and
>the one open spyhole but the pottery piece inside looked the same. I
>was starting to feel the first hints of apprehension.
>
>15-minutes later: The burner was turned on 1/2. What a roar!!!! I
>knew that this was producing about 90000 but/hr now and I had about
>9cu. ft to heat. I guess I just have to be patient!!!
>
>5 minutes later: Almost before I knew it the chamber became toasty
>orange and the vase inside began turning an ugly kind of spotted grey.
>
>5 minutes later: The first hint of glossyness to the surface of the
>vase within. A wash of relief!!!!
>
>5 minutes later: The gosh darned whole thing was shiny, like some
>molten metal!!! Yippiii!!!!!
>
>Turned off the burner, opened the trash can with 2" of shredded paper
>inside, got the tongs, said a quick prayer and prepared to jump in my
>pond if something caught fire!!!!
>
>I lifted the fiber shell and immediately the vase turned from orange
>to green as a wash of superheated air hit me in the face. I quickly
>grasped the vase in my tongs and dumped in unceremoniously in the
>trash can and put another 2" of shredded paper on top and closed the
>lid. I took the next piece, a large plate, and put it on the kiln
>shelf and put the fiber shell back on, which had by now burned a nice
>circle in the green grass I put it on. (I thought that the metal
>plate I brought out for this purpose looked a little green!!)
>
>I won't go into the other two firings now, but after about 30 minutes
>I removed the trash can lid and lifted my piece out and dunked it in
>water. After all the soot and carbon got washed off it turned out
>the ugly green I had saw when I put it in the can was replaced with a
>nice golden metalic surface with hints of red copper, the inside
>looking like the shell of a clam or oyster. Nice!!!!!!
>
>With everything that could have gone wrong I still got three pieces
>that looked great!!!!!!!!!!!! I am glas that that one day God did
>not choose to exercise God's sense of humor!!!! They were glorious
>(of course this was an emotional biased account of their quality!!)
>
>I can't wait to do it again!!!!!!
>
>If you would like to see the results go to :
>
>http://www.sdpottery.com/Ceramic_Misc/New_Arrivals.htm
>
>
>***************************************************
>Steven D. Lee
>SD Pottery - The Little Texas Potter
>http:\\www.sdpottery.com
>millenial_age@yahoo.com
>14341 FM 112
>Thrall, TX 76578
>512-898-5195
>***************************************************
>
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