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....