Friday, April 26, 2013

Making more Adjustments to Kiln Arch

Opening the Kiln from the Top
Hi everyone. It's been a while. Guess I've been Facebookin' more than bloggin'. Thought I'd share a little bit of behind-the-scenes work that might be of interest to some folks. I've been dealing with some brick-slipping issues in the arch of my wood kiln. I ignored it for a while - it was just one brick.

However, the brick kept slipping. This being the first kiln I ever built, I asked around and other potters said to not worry. But the brick kept slipping. I decided to open the top of the protective shell where the slippage was occurring. I did this a few weeks ago, and I ended up pushing the one offending brick out of the top of the arch, and replacing it with a new brick of the same shape, slathering some wet fireclay onto the surfaces where it was slipping past other bricks.

I thought the new brick fit tighter, and this might solve my problem. I also got a better view of the key at the very top of the arch which had cracked near the offending brick quite a while ago. What I concluded was that the jagged crack had kept one section of the key from settling back down during expansion and contraction while the kiln heated up and cooled.

I decided to cut into the crack to try to allow the two pieces of the key to settle evenly, but my saw blade would only go about halfway into the crack.

After all this, I replaced the kaowool insulation and the protective shell that I had cut away, and proceeded to fill the kiln and fire it.

Upon unloading, I found that I now had two bricks slipping, and they were slipping further than the previous single brick. So, it was time for more drastic measures. Lucky for me,  kiln builder Andres Aillik of Estonia who helped build some wood kilns in Seagrove was in town. He and David Stuempfle (wood fired potter) dropped by yesterday and we decided the best thing to do would be to cut a small section of the key out of the kiln (including the crack), grind the crack smooth and place it back where it belongs, leaving a small space between it and the other sections of the key.

So, I borrowed Ben Owen's gas-powered concrete saw, drove to Carthage for a new abrasive blade and did what was required. I had to support the section of arch from where I was removing the key, then remove two arch brick on either side of the key section I would remove.

Perhaps, it will all make sense when you see the pictures:

Here's the previous repair with the new brick and crack showing.

Supporting arch for today's repair work

Bricks and key section removed (rope held key section during cutting)

Don't want crud slipping between brick or onto pots.

Finished job. Hope it works.