Post by smarty on Mar 16, 2013 8:29:30 GMT -8
I have posted some pictures of the batchbox I just struggled to get out the mould here: www.box.com/s/uej8kim5f40xqp3w6k6h
For anyone hoping to do multiples, as I was, from a single wooden master I would say good luck! Although I put a 2 degree draw on the master it was a right pig to get the bits out from the concrete. Also although I had sealed and waxed the master the cement that was cast in contact with the wood was rather powdery meaning that the nice smooth finish to the cast was lost.
The struggle to get the bits out of the mold has left its mark on any details like the lip for the peterplate to sit on which has crumbled somewhat.
The end result is therefore far from perfect but I learnt a lot along the way which is what it's all about really. I think the finished thing should be usable even though I didn't get all the air bubbles out.
My advice would be to anyone trying to use wood as a master to maybe consider sticking a sacrificial layer of the very thin polystyrene paper - that I think you can get at wallpaper retailers - to the master. Stick it to any of the larger bits where 2mm of paper is not going to matter too much in terms of messing up the various parameters that the thing is designed to meet.
If I were to do this again I think I would build a mock up in plaster of paris first and then pour hot melt casting rubber round it. But that is for the next project!
My thanks to Peter for posting the design. I hope I will be able to come up with some ideas of my own based on this kind of thing to repay the favour some time.
On the top in the photos is my first ceramic shell chimney made out of clay slip and grog backed up with clay slip and fiberglass.
I'll do a separate post on this process soon for everyones information.
Cheers
For anyone hoping to do multiples, as I was, from a single wooden master I would say good luck! Although I put a 2 degree draw on the master it was a right pig to get the bits out from the concrete. Also although I had sealed and waxed the master the cement that was cast in contact with the wood was rather powdery meaning that the nice smooth finish to the cast was lost.
The struggle to get the bits out of the mold has left its mark on any details like the lip for the peterplate to sit on which has crumbled somewhat.
The end result is therefore far from perfect but I learnt a lot along the way which is what it's all about really. I think the finished thing should be usable even though I didn't get all the air bubbles out.
My advice would be to anyone trying to use wood as a master to maybe consider sticking a sacrificial layer of the very thin polystyrene paper - that I think you can get at wallpaper retailers - to the master. Stick it to any of the larger bits where 2mm of paper is not going to matter too much in terms of messing up the various parameters that the thing is designed to meet.
If I were to do this again I think I would build a mock up in plaster of paris first and then pour hot melt casting rubber round it. But that is for the next project!
My thanks to Peter for posting the design. I hope I will be able to come up with some ideas of my own based on this kind of thing to repay the favour some time.
On the top in the photos is my first ceramic shell chimney made out of clay slip and grog backed up with clay slip and fiberglass.
I'll do a separate post on this process soon for everyones information.
Cheers
