How would you like to use a plain old ceramic kiln with no controller to make the most beautiful pieces of cast glass? Well that is what a pot pour is.
Also referred to as an aperture pour, the idea is to put scrap glass into a clay flower pot and take your kiln up to 1700F, at which time the now molten glass will drizzle out the holes in the bottom of the flower pot, hopefully creating intricate designs.
This is so simple to do all you need are something to hold the glass in like terra-cotta flower pots, something to catch the glass and pot supports.
We use $1-$4 unglazed terra-cotta clay pots from Lowes. We do not kiln wash them. We drilled extra holes in the larger ones. Pot sizes are generally 2″, 4″, 6″, and 8″. Try to purchase “azalea” type pots as they are wider at the base which is better – trust me. Drill larger holes in the bottom of the pots to get the glass to flow out more smoothly. In the 6″ and 8″ pots drill multiple holes, perhaps 6 to 8 as this will create more interesting designs. Be sure to use masonry drill bits. They will not crack the pot, are inexpensive and last forever.
The Kiln Wash
I use Bullseye and do a 1:1 or 1.5:1 mixing ratio with water. Yes I know this is thick but it protects the shelf at these high temperature.
These are optional as you can let the glass just fall on the kiln shelf. Be sure to use lots of extra thick kiln wash. If you are too nervous to let the glass fall onto the kiln shelf then use ceramic pot saucers a few sizes up to catch the glass. Definitely kiln wash these. You can also use metal circles/frames to contain the glass so it does not spread out too far.
The Pot Holders
You need something to suspend the pots of the kiln shelf. What I do is lay some kiln brick on its side and the lay long kiln posts across to suspend the pot(s). What I really like is to get some old kiln shelves and cut 1 1/2″ wide strips about 20″ long. They are cheaper that long kiln posts and are not as high.
The Simple Process
1.Put lots of kiln wash on your shelf. It does not have to dry all the way as the running kiln will take care of that.
- Set up your kiln brick and posts to suspend the pot(s).
- Load up your pot with glass. Make a note of how much. Too much and it will overflow so be careful.
- Put pot in kin – really!
- Turn kiln on high and let it run for about 3 hours but check the temperature. Open the lid at about 1700 degrees to see if all the glass is out. Let all the glass run out.
- Turn off kiln and flash cool to 1100 degrees. Close the lid and the piece will anneal as the kiln temperature reduces naturally. If you get nervous, turn it on low at 960 for an hour or so.
- Be sure to let the piece cool thoroughly.
- You will need to clean the backs of these pieces. I use sandpaper for the small ones and a 60 grit flap sanding disc on a hand held grinder for larger ones. The flap sanding disc takes the kiln wash off in 2 seconds – no kidding. To get even the fine grit off soak them in muriatic acid for 30 minutes and hit them with a wire brush. Muriatic acid is nasty so use hand, mouth and eye protection.
That’s all for now. So long and keep kilning!