Wednesday, October 22, 2014

Banded Trotter Casts

I had an idea to try something different with the cast trotters. By laying the mould down at an angle, diagonal bands of colour and finish have been introduced to these pieces. One is topped with cold cast aluminium and the other brass.

There are challenges to this process. Firstly the glitter does want to settle out of suspension. There seems to be a ratio of glitter to resin that results in minimal settlement for maximum colour. Below that and most of the glitter drops out and your left with very clear cast. Above it and the mass of settled glitter at the bottom is obvious and the cast lacks brightness. But I'm not sure what that magic mix is, I'm still going by feel.

The other contributing factor is the mix ratio of catalyst to resin. A hot mix with more catalyst will stiffen quicker, becoming more viscous and holding more glitter before it has a chance to settle. Hot mixes do however tend to be slightly cloudy, shrinkage seems a little more pronounced and there is a possibility of cracking.

The problem with shrinkage is that as each layer cures, it pulls away from the inside surface of the mould leaving a slight gap. When the subsequent layer is poured over the top, it seeps down the sides forming a skin over the previous pours. Looking at the cast on the right, you can see some green glitter has managed to work its way right to the tip of the trotter. It took a lot of sanding to get that green skin off and I was not entirely successful in that regard.

Despite all that, I'm very happy with the way these turned out.

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