tomhumf

Thanks, yes I will definitely only change one thing next firing, but will keep the bisque setup the same. I think the burner port change was good. Now when I candle the kiln at the start the flame seems like it's really happy to go into the kiln, it was pretty cautious before at that stage. My method is to start reduction at 900C and just have damper in enough to get positive pressure at bottom peep - this still has temp climbing slowly. I open up the damper a little at stages as the kiln climbs maintaining positive pressure at the bottom peep. This has given good results with pretty even temp and reduction throughout the kiln. In the latest firing I was expecting to keep the damper closed more due to the expanded burner port size. I started the damper and gas at the same as usual but was surprised at getting more flame from the bottom pee - Schedule below. As firing progressed and I saw larger flames than usual at bottom peep, this continued through the firing. For the first three stages below I keep to the same settings even though the flame from the bottom peep was bigger. At 10.40 I opened to the largest damper I usually use about an hour ahead of my usual schedule as I as concerned I was getting too much reduction. 9 damper 1.5" 900 9.40 damper 1.6" 1030 10.15 damper 1.75” 1100 10.40 damper 1.8" 1145 11.09 1184 11.40cone 8 down 12.15 kiln off

I didn't see those last two comments until just now. I realise this is a mistake but I did change the burner port opening and bag wall setup. I can put them both back how they were but I understand changing more than one variable isn't a good idea. I made the burner port an inch bigger https://photos.app.goo.gl/WdD8L4Yemrier7ba9 And setup the bag wall like this. https://photos.app.goo.gl/1GyoYCLKiGkGaHKV7 The bisque was good, a tiny bit of reduction at the rear but much better than previously. The glaze firing wasn't very good. The top half was fine, if a little overfired at the back. The bag wall bricks have just been moved to see bottom shelf in this photo. The red area was a bit underfired. The firing took 8 hours instead of the usual 10. Strangely I was getting more reduction flame from the bottom peep than usual with same gas and damper settings. I didn't see any flame from the chimney though in later stages which I usually do. https://photos.app.goo.gl/nwK3KboUvWmM5VJg7 The bottom shelf was really underfired and oxidised. The front section will all have to be refired. https://photos.app.goo.gl/6sefBNYdgjrSvRQf9 https://photos.app.goo.gl/wkC6oE7MMyXafNxu7 So I guess it's hard to say what's going on as I changed both things at the same time. My idea is to do the next bisque the same way as this but to do the glaze with the burner port blocked to the same size as I had it previously. Feels like I should take one of the bricks out the bag wall and have bigger gaps but I guess I shouldn't do that as well. Any ideas?

Ok, I'll use the two cut bricks I showed in the last photo as target brick to start with then, I think that makes the 1/2 size you refer to? I don't know why but the masonry disc I have really struggled with these bricks so want to avoid cuts if possible. @Bill Kielb I have actually considered adding a hole on the back wall like you suggest. So this would have a different affect to opening the chimney damper more? The damper is currently about half open, it seems any more and I just need to use more gas to maintain climb. I was thinking of cutting a half brick out at red marks. I'll try the new bag wall setup before and see what happens with that first though. https://photos.app.goo.gl/cTStyTC1FYd6cpsN6

Thanks @Mark C. Yes I know it's a bit crazy having one burner but I've used this kiln working full time for the last couple of years. If I could get this working a bit better I think I'd be happy never having another burner. I will put it back to previous setup for the next glaze firing like you suggest. @neilestrick For the next bisque I'm going to try your suggestion. I layed it out today like I think you meant? There is about a 1" gap between each brick in the bag wall. Not sure if the target brick is how you meant? There isn't much gap for flames to go around. https://photos.app.goo.gl/6Hnu1hFAVMF4wToK6 https://photos.app.goo.gl/AfYRrtvkjUV2G8yh6 I find it nearly impossible to cut heavy bricks with my saw, I do have a couple of thin bits I could use stacked up but that may be a bit wobbly. https://photos.app.goo.gl/FyaP2BD2tzBeKC6L9 I'm right in thinking the bag wall and target brick should be heavies? I could cut some HTIs in half so flame channel is wider if that's an option. I can't really move the shelf left as I'd loose stacking space under the arch.

I'm firing my gas kiln with one burner , input and chimney output shown in blue. It's not an option to add another burner at this stage. https://photos.app.goo.gl/PjcvCarps8tqn2tA8 I've always had a problem that the back lower and middle section is reduced more than elsewhere. Even with damper adjusted to wider and lower settings, I can't get properly oxidised bisque there, and glaze is a little over reduced compared to rest of kiln. https://photos.app.goo.gl/EhiX3FfJJHWfwZwV6 I recently added the bricks in green to deflect some flame into the front section more, I'm happy with how those helped. The back section here is how I've had it set for ages, it gives too much reduction at back bottom and middle. https://photos.app.goo.gl/w3zRqkvzDfTe9VLN7 Last firing I added the bricks in red. The middle section improved slightly I think, but the bottom back got super reduced, the tankards in red I probably won't even attempt to glaze. So this seems like I've made things worse overall at the back. https://photos.app.goo.gl/ttvPXqK7Px6MbN7S9 I'm wondering now if I should just removed everything at the back in yellow? Just make more space there, have a tiny one brick deflector on the back wall, and keep the green bricks at front. Any thoughts? Thanks