Plaster batts have been sorely needed. Lots of practice throwing has resulted in lots of wet clay waiting ot be recycled. Time to do something about it.
Fortunately one of the team in the studio was also ordering plaster and I joined in with her to get a sack of potters’ plaster 2 (apparently better for batts than ordinary potters’ plaster.)
The only book i had with instructions in was American, and had the measurements in Us imperial, which fried my brain slightly till i though to use the trusty internet to get the conversion rate of quarts to fluid ounces. 40 it tells me, so mixed up 6 multiples of 1 quart water to 23/4 lb of plaster to make about a washing up bowl’s worth.
This was poured into a mould made up from a melamine board base and clay walls. The clay is kept seperate for use with plaster only. (Plaster in clay in the kild apparently does terrible explosive things to pots so a good idea to keep them strictly segregated.
It took much longer than i expected to get thick enough to pour – about 15-20 mins.
I also included some folded up chicken wire into the mould and poured the plaster round it, to reinforce the batt once dried.
All told I was quite pleased with how it all went – particularly as I had never worked with plaster at all before.
Troubles in translation
Then that evening I was telling D about my adventures and she made a casual passing comment about US quarts being a different size to UK quarts. Rats. I looked it up, it’s true. 1 UK quart = 40 fl oz. 1 US quart = 33.3 fl. oz. The book is very explicit that for repeat use it’s best to follow the ratios precisely to get the strongest possible plaster.
So, the next day saw me getting the sack out again to remix a new batch using US quarts. I didnt have any more chicken wire, so the second one is not reinforced.
They are still drying out, but so far it does seem harder. Hopefully the first one will still be safe to use…