Hopefully I have learned enough from the last two experiments to make a good casting this time.
I set up the wok again with Plasticine walls and a slightly larger saucepan lid and made up a much larger batch of plaster hoping to cast the whole thing in one go.
I poured the plaster into the wok and started swirling it genlty, hoping to make it stick to each part of the surface – impeded somewhat by the thick layer of petroleum jelly. During the next 10 minutes the plaster gradually thickened and began to build a smooth layer over the whole surface area. As I swirled the liquid it behaved like a tidal wave coming around and around in a regular sweep but as it began to set it grew thicker and was in danger of leaving a literal tide mark in an unsuitable way. I set the wok down to rest and watched as the excess plaster solidified in an almost even spare-tyre kind of shape in the centre.
I decided this time not to try to manipulate the surface in any way and I am pleased to say that it is smooth and even, though somewhat thicker towards the centre with a discernable swelling about 2 cms from the pan lid, it looks pink here but it dries white.
I suspect that the outer/upper edges are fairly thin and that I will need to make another pouring.
2 thoughts on “Experiments in casting”
I’ve used woks before as “slump molds” for slabbed clay, and cast plaster in them for the opposite, “hump molds.” But have never tried to cast an actual form inside a wok. A fascinating exercise!
Oh it does work pretty well but vaseline is not the best release agent, its leaves brush marks in the plaster. Of course the inside is not as smooth as I would like, I have a curved cabinets scraper that helps – scoop round on the inside before the plaster is dry. Also I got rust marks from the wok but an expert told me, just turn on your over (domestic) to about 50C then turn it off again and leave the wok and plaster in there till its dry, there’s no time for the rust to get going.