Urgh - just opened my kiln up to find the shelf has broken into 2 equal parts :'( There's £75 to pay for a new shelf now :'( :'(
My fault I think as I was doing my first open cast mould and placed the rather large heavy mould on top of the shelf which in turn was suspended on the kiln posts. I think the weight was too great as the shelf cracked down the centre. The mould seems to have been weak as well and has broken although no escape of glass I'm glad to say.
In future I'll put a layer of vermicullite on the kiln floor and lay the mould on that.
You win some, you lose some....
Gutted :(
Quote from: Sandera on January 29, 2012, 04:47:38 PM
Urgh - just opened my kiln up to find the shelf has broken into 2 equal parts :'( There's £75 to pay for a new shelf now :'( :'(
My fault I think as I was doing my first open cast mould and placed the rather large heavy mould on top of the shelf which in turn was suspended on the kiln posts. I think the weight was too great as the shelf cracked down the centre. The mould seems to have been weak as well and has broken although no escape of glass I'm glad to say.
In future I'll put a layer of vermicullite on the kiln floor and lay the mould on that.
You win some, you lose some....
Have you tried Hobby cerammicraft at Hook? I am sure my last kiln shelf wasent as much as that.
Or Pottery Crafts
http://www.potterycrafts.co.uk/Products/00100007
Just check shape and size and you'r a winner.
Potterycraft do have a good range and even if they are not quite the right size they can be trimmed with an angle grinder or a tile saw. I cut some kiln shelves into strips to use as casting dams using a water cooled tile saw it cut them very easily.
It's also about thermal shock of the shelf. A large mould on the shelf makes it colder under the mould than around it on the rise and vice versa on the way down. I've done it myself before. Raising the mould even 10 mm above the shelf reduces the chance of breakage due to large moulds on top.
Stephen
Not sure if your shelf was square or round or whatknot but did you put props in the middle underneath to support the shelf too? I've luckily never had a shelf crack on me but I'd also shop around for prices as the last shelf I bought which was 50cm square was nothing like that amount.
Aggh! Already ordered it online. I hope it doesn't happen again but at least I'll know where to go for a cheaper version.
Thanks for your pointers to cheaper suppliers and suggestions to avoid this happening again. I knew I should have asked here first!