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Slumping Bottles Vertically
Today’s article was sparked by a question from a reader:
“Have you ever slumped a bottle vertically in the kiln, I want to achieve an artistic slump rather than a melted pile. I figured if anyone had tried it it would be you. Thanks, Andy”
Oddly enough, I hadn’t ever tried it, so I thought I would give it a go.
First I measured how deep my kiln is, this helps tell me how tall my bottles can be.
It looks like I have 9.5″ of kiln height. I’m measuring from the shelf to the top rim of the kiln. BUT, I have a very old kiln, and the elements do extend down into the kiln space.
So, I’d better subtract 1.5″ for element clearance, giving me a total height of 8″. Now, how tall are my bottles:
I’ve selected two small bottles, one airline size Bombay Sapphire and one baby food jar, I’d like to see what a taller, narrow bottle does, and a lower, wider bottle. I also needed bottles that I had identical multiples of. I’m firing these using my standard firing schedules so I know where to start, rather than just choosing a random temperature.
So, here we go, these two are fired using a full fuse schedule:
Next up is a Tack Fuse Firing Schedule (100 degrees lower than a full fuse):
And these two at a Slump Firing Schedule:
Here are the bottles next to each other so you can see the progress:
Things I learned:
- Bottles aren’t an even thickness all the way around or top to bottom
- The thin parts bulge out and slump first
- Bottles don’t slump straight down (see previous)
- Wider, shorter bottles are more predictable
- The ideal slumping temperature seems to be somewhere between a slump and a tack fuse (about 1400)
Reader additions:
Hi Jodi – I tried this with a green beer bottle. Thankfully, I was checking it because it went sideways and
hit the side coils. I was able to remove it before any harm was done. -Connie
If you try this and like your results, please let me know!
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