Plaster casting

Mould of 'Ibu sleeps'
Mould of 'Ibu sleeps'

Hands up. I’m not a caster. My preference is to pay others to cast for me. However, it’s Easter, time is tight, and my normal caster will be away. And the last time I asked him to cast a plaster sculpture for me he looked at me incredulously and said “why don’t you do it yourself, it’s so easy?”. I need a cast of ‘Ibu sleeps’ for Guildford Cathedral. I also want a couple of plaster casts of smaller portraits for our ‘Tactus’ group show at The Gallery in Cork Street. I should be able to cast unaided – surely?

I put it off for a day. But the weather forecast talks of the end of the unusual hot spell, with rain to come on Wednesday. This is my incentive. On Tuesday morning I am in Brewers comparing plaster buckets before I know it. The kitchen and patio descend into chaos as I unearth moulds and my casting equipment. The Workbench is hauled out of the shed and covered in a plastic sheet. The sack of plaster is dragged into the garden.

Flexible plaster bucket and bowls
Flexible plaster bucket and bowls

First step is to wash out the three rubber moulds, and dry them in the sun. Find that the rubber of my mould of ‘Ibu sleeps’ has come away from the jacket. This means that there may be an indentation in the cast at the back of her neck that I don’t want. This is when I realise/remember how inexperienced I am at mould-making and casting. Expert advice is needed. I ring the foundry who had made these moulds several years ago. Their suggestions, from the least invasive/aggressive to the most: (a) Vaseline on one surface then press hard against the jacket; (b) Evo-stick on clean and dry surfaces, following instructions on pack; and (c) Superglue, if all else fails. After a trip to B&Q I thought I had all types of glue known to humankind. However, I only succeeded in making a mess. The rubber had also started to split. Agghhhh.

Phone call to fellow ‘Tactus’ group show member Lynn Warren. She is a very experienced mould-maker and caster. She suggested trying other glues like PVA or double-sided carpet tape.  She has heard that a small metal tack could be used, but had never tried it. She thought that the splits in the rubber would self-seal when the plaster was poured in, which was reassuring. She passed on two useful tips. To avoid the buckling of the rubber when storing moulds, pack them out with plastic bags.  To avoid the rubber splitting, you need a thicker layer of rubber. Next time…

To cut a long story short, the other glues and tape didn’t work either. So went ahead and cast the two smaller sculptures – successfully. So this morning, got to B&Q early for the stronger Evo-stick (Impact glue). Made even more mess. Rang the foundry again this morning for tips on the splitting rubber. They thought it would self-seal too. But suggested trying a gel Superglue as it ‘goes off’ quicker. Then adding a weight, leaving it for two hours.  Yet again down to B&Q, which by now is heaving with Easter holiday DIYers. I now have all glues known to humankind plus one.

So – here I am, with my fingers-crossed. I have applied the gel superglue as per instructions. I have laid a bag of sand over the area. Now I need to wait for a couple of hours. If all that fails I will try and cast as is, dealing with the consequences (indentation and a messy mould) later. Wish me luck.

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