Sunday, 7 February 2010

Manipulating Slumping Glass in the Kiln

In my view the protection you need at slumping - or combing - temperatures are:

Face and hair protection – a face shield with a coating to reduce the infrared glow is ideal, but expensive

Good heat protecting gloves – do not cut corners here. You need something more than leather or welders’ gloves.

Heat reflecting sleeves – the aluminised ones work very well

A reversed denim jacket to protect your chest - you don't want hot buttons!

A helper to hold the lid/door open

The tools

Wet timbers - at least 40mm in one direction, square is probably the best. They need to be at least 600mm long - a metre is better.

Wet wood handles on any metal tools.

In the case of manipulating glass at slumping temperatures, you need two soaked pieces of timber. If you try to manipulate with one stick you will just push the piece around the kiln. Two sticks allow you to move the glass on opposite sides of the mould toward or away from each other without shoving things around. Glass is amazingly stiff at slumping temperatures. You will wonder how it moves at all when you have to use so much pressure to affect the piece!

Note also that the timbers must be soaked. If they are not they will certainly leave marks on the glass.

When the timbers began to smoke, it is time to close down the kiln - whatever manipulation stage you are at - and let the kiln heat up again while your sticks get wet again.

You need a second person to help with this kind of manipulation in the kiln. They are the door holders, fetch and carriers and anything that needs to be done while you are pushing the glass around the mould. Perhaps after a few trials, you would be able to do it without help, but it is always easier and safer to have help.