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Member Since 01 Feb 2013
Offline Last Active May 19 2013 01:40 PM

Posts I've Made

In Topic: Gas kiln won't heat up above 650C/1200F

10 May 2013 - 01:23 PM

Hallelujah! Posted Image Posted Image
I finally sorted it out. The reason was quite simple - I had to throw away the pressure reducer. For some reason I thought it's not ok to run a burner without it, but I talked to another Ukrainian potter who uses similar setup and he said he runs it without the reducer.
Posted Image

So no other tweaks were actually necessary if I got rid of it on my very first firing. The burner size was ok, the holes were ok, the flu, the draft etc. were ok.
I climbed to 1040C/1900F in about 8 hours and the burner was only 70-80% open, so I believe I could easily climb to 1250C/2280F if I wanted. But I was firing earthenware so 1040C/1900F was just fine.
When I opened the burner some more the reduction flame ran out the top hole. That is so exciting! Posted Image I didn't actually need it for bisque firing, but now I know I can do reduction firing if I want.

Check out the video.

Here is the picture of the fired pieces I made this morning.
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I have some questions about color changes but will post it later in a separate topic.

This is what happened to the shelf:
Probably it will live a few more firings and then I'll buy some good kiln shelf, because this one is not.

So this topic is now in resolved status http://ceramicartsda...ult/biggrin.gif
Thanks to everyone who tried to help, I really appreciate this.


In Topic: Gas kiln won't heat up above 650C/1200F

07 May 2013 - 10:37 AM

bigDave, thank you for the encouragement, it really helped, especially about the chosen ones!
So the next day I decided to decrease the kiln inner volume by putting a fiber wall about 2/3 from the front lid and cut the shelf on half. And I didn't put too many pieces in there. So I noticed that the temperature climbed much quicker than before. I got to 500C/932F in about two hours, but then again it just stucked. So I thought what if I somewhat close the top hole. I used some pieces of fiber and and made the hole about 7cm, while it was 10cm. I also closed bottom hole a little. To my surprise the temperature started to climb! I also tried different burner positions and noticed that it should not be too far out, just about inlined with the entrance. So in about 2.5 hours I got to 700C/1292F. Then it stuck again so I closed the top hole even more and it started to climb! In another 2 hours I got to 850C/1562F. And it seemed like a limit because no tweaks I tried helped.
Anyway I was so happy even with this result Posted Image The pieces were glowing orange, what a joy Posted Image

So the conclusion is the holes should not be big and the pieces should not be packed to tightly. I think there's some perfect proportions for the holes I'll have to find.

The next day I went and bought a bigger burner with side holes. I also wanted to buy a splitter to be able to connect two burners, but couldn't find it. I removed the wall in the kiln and reverted to original volume. Everything went fine, but at 800C/1472F it stucked. So I inserted the burner more in the hole (it was about 2in away) and it climbed to 850C/1562F and wouldn't climb any more.

Maybe the shelf is making problem? It's actually an insulation board and it doesn't heat up like a special kiln shelf should.

Mark, you are right, I know about the tank freezing, I put it in a water container and added hot water there.

In Topic: Gas kiln won't heat up above 650C/1200F

05 May 2013 - 04:11 AM

Mark, I agree that the burner is too small. I think I'll have to buy a bigger one. Or maybe I can have two of the same size? Is it ok to fire two burners from the same tank? I worry that the pressure will split between two burners and it won't give any difference. Maybe I have to get two burners and two tanks?

I just did a test and boiled 1liter of water with fully open burner. It took 4m30sec. Can I estimate burner BTU with this information? We don't use BTUs here because we use metric system, so I don't really know how to calculate and convert it.

In Topic: Gas kiln won't heat up above 650C/1200F

04 May 2013 - 12:34 PM

Today I fired it again and couldn't even reach my previous result of 650C, now it climbed to 600C only. :-(
I am so disappointed...
Anyway, this is what I did - made both holes bigger (especially the top one) and pull the burner out oh the hole.
In 5 hours it climbed to 520C/968F just fine and then stalled... 2 hours more and only +20C. Then I decided to cut the top hole even bigger and pulled the burner even more out. It then raised to 600C and stalled. I tried everything - adjusted the burner to different positions, I tried to blow some air with a room fan, I even found some oven chimney pipe and inserted it into the top hole, but that actually dropped the temperature to 550C.
I ran around for almost 12 hours and nothing helped, so I just turned the burner off and feel very bad now. Don't know what to do... Maybe I have to switch to vertical design?
Or maybe I have to switch to woodworking...

In Topic: Gas kiln won't heat up above 650C/1200F

04 April 2013 - 04:19 AM

neilestrick, chimney?? Oh no.... I hope I'll make it work without it. This is a low-end project and chimney will ruin the whole concept :lol: :D
But in case I decide to make one, what would be the height of it?

Marcia, the shelf is 40x60cm and 10cm away from the back wall, do you think that's enough?

, pictures would be great! Thanks