More work with styrofoam

I’ve made some additions to my .. according to the statistical accounts .. most visited page Shaping Styrofoam which is under ‘Shaping’ in the Materials section. One is that epoxy resin glue works very well to bond it! I’d always assumed that epoxy would damage it, in the way polyester resin does .. but no, it doesn’t dissolve it and the bond is very strong! .. and I’ve used the cheapest stuff around, the one from Poundland! The other addition deals with preparing styrofoam prototypes for mouldmaking and I’m reproducing the entry here. I’m also finally managing, by the way, to hint more at what I’m up to at the moment .. working towards a solo exhibition of my current sculptural work which will take place in or around September next year!

If a styrofoam shape is being made as a prototype form intended for casting it doesn’t need to be made particularly durable .. it only needs to withstand silicone rubber being either brushed or poured over the surface. It does however need to be sealed, because if not the silicone rubber will grab into the surface too much and become very difficult to separate. Vaseline (petroleum jelly) is an ideal temporary sealant in this case because it can be easily brushed or rubbed into the micropores without damaging the surface. If care is taken not to use too much of it the Vaseline will also even out the surface, although I’ve noticed that most of it is absorbed into the silicone anyway. The only problem is .. it’s very difficult to see where you’re applying it! The solution is to colour it.

base unit shaped from styrofoam

This is one of many base-unit prototypes I’m making for a sculptural work which I can describe best by its working title .. ‘the ridiculously organic construction toy’! The components of the ‘nature driven’ form system will be assembled by means of holes and joining-plugs, hence all the holes in the base. Once I’ve made the mould from this the base units will be cast in polyurethane. I found a laughably easy way to carve out clean holes in styrofoam and I will explain this method sometime soon.

pigmented Vaseline

The best way to colour Vaseline is to first mix a little powder pigment, in this case half a teaspoonful, with roughly the same amount of Vaseline to make a thick paste not unlike tube oil paint. I chose the ultramarine here because it’s a strong pigment and finely ground, combining smoothly with the Vaseline .. some powder pigments may be grainy or clump a bit, which is not so good! The half teaspoonful was sufficient to give a strong colour to c. 50g of Vaseline when I added this to it, but one could use far less pigment. For example, the pigment will stain a porous prototype, so you have to bear this in mind if you want to keep it or if it’s an object of value.

using coloured Vaseline to seal styrofoam

There were a couple of larger scratches in the surface which I needed to fill and I’ve found that soft modelling wax (this one is the Terracotta Modelling Wax from Tiranti) is the easiest to use, worked carefully in with a brush.

filling larger holes with modelling wax

That’s actually it .. surprisingly short this time!

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