Saturday, 3 July 2010

Nasty Nick Part 4: De-Moulding

Next day, separate the mould halves - as mentioned above, you insert screwdrivers into the cavities formed by the clay pieces you added before pouring the second half. Note screwdrivers in plural - you should have applied the clay pieces on opposing sides of the mould, and using two screwdrivers, one in each side, you apply equal force to both sides of the mould simultaneously. This minimises the chances of splitting the mould, because you will be applying a tremendous amount of force to split the halves apart. This is another nerve-wracking procedure...

Dont worry about any damage to the clay sculpture as the halves part - you'll be destroying it anyway as the only way to remove it from the mould is to dig it out. Here, you can see the start of this process:

Here's the front of the mould after the clay has been removed. Note the markings in red pen - they highlight holes in the plaster, caused by air bubbles during mouldmaking. I suspect this was due to a combination of slapdash application of the plaster and beading caused by a lack of dulling spray.

I strapped the two halves together with bicycle/luggage bungee ropes for a couple of days so that as it cured, the two halves wouldn't warp.

The mould will be strapped together in exactly the same way when pouring the latex, of which more later...

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