Opening Kiln

[Suse]

Hi everyone

I am another newbie.  Please forgive me if I'm asking astupid question or one that has been asked and answered previously.

I've been fusing, slumping and draping for just a month with varying degrees of success. 

My only question at present is when the program is over and my kiln is just cooling down - at what temperature is it safe to open the kiln for both the glass items and kiln?  Looking at previous postings it seems to be anywhere from 100 degrees down?

Also I know there are times during the firing schedule when it is safe to open for viewing etc and times when it's a complete no no.  Can you tell me these times too?

Many thanks
Sue 

[Glyn Burton]

Hi Suse
The temperatures to be careful with are the stress points that is to say between 540 and 450 (as a rough rule of thumb) and at around 200. If the glass is 600 or over there is no problem at all in fact it can be very helpful to peek into the kiln when you are slumping or draping to see the state of play as it were.
If you are slumping at say 710 and you have the desired degree of slump/bend then it is perfectly safe to leave the kiln door open a little to "crash cool" down to 600 in order to stop the movement of the glass, as long as you anneal it properly there will be no problem.
Remember
Open the door a little way to peek in don't throw it open wide.
Don't get too close or you may loose the front of your hair and eyebrows.

Hope this helps

[jeannette]

Hi -

Someone may have posted this before, I don't remember if this is a stumble upon special or not.
http://www.bullseyeglass.com/images/stories/bullseye/PDF/TechNotes/technotes_04.pdf
Its useful to understand what's happening with the glass at different temperatures to answer some of your questions here
HTH
Jeannette

Credit
http://www.frit-happens.co.uk/forum/index.php?topic=37.0

[Suse]

Thanks I really appreciate that
x

[Krysia@No98]

When i told my tutor at uni that I opened the bead kiln at 100, she gasped and told me I was very brave.  she doesn't open the flat glass kilns until they get to 8/70 and even then it's just a crack then when they get to 50 she opens it completely but doesn't allow any of it to be moved until they are just warm to the touch.  It means that the kilns she started at 9:30 ish the night before generally aren't ready until 3/4 the following afternoon to put new work in.

[jeannette]

Ya know, I leave mine to cool to 36 ish before I look in, I just never find myself in an emergency kiln situtaion - but it's a hobby for me. Impatient definitely, justified emergency - not so much