Spent the last four hours putting the new plasticine that arrived this morning to good use.
layering the bottom of each box with a layer of approximately 10mm of plasticine to the box, I pressed lightly on the models into the pl, just to hold them. This was on the items that only needed the one side reproducing.
and rubber will be poured onto these, and that is it. mould done……….as simple as that, and when used the resin will just be poured into the indentations in the rubber moulds.
the ones that have to be in two halves, are made slightly different.
A thicker layer of plasticine is laid into the base of the box so that the model to be replicated can be pressed home halfway down the model.
the finish of these pressings is important as no seepage of rubber must be allowed between the plasticine and the model, ir the seem line between the two rubber halves becomes raggedy, messy and needs much more sanding to produce a nice line and finish.
therefor the plasticine is pressed home against the model to stop gaps.
Finally the two halves, once moulded must fit exactly against each other to help join the two halves perfectly with no disjointing of the model [ when this happens occasionally, you can pick up a casting and it looks as thogh one half has slid down on the other half….it often happens when someone is casting a lot of one item, and doesn't reseat both halves perfectly.
to avoid this, locating tab holes are pressed into the plasticine …. [ I use the end of a pencil], and once the first layer of rubber is laid, and the plasticine is taken away, they stick proud of the rubber.
at this point, I ran out of my recently bought 1.5 kilos of plasticine, and so could do no more.
I was going to cast the rubber tonight, but believe it or not, it takes quite some mental concentration to make the boxes and place the models in to maximise the amount placed for the minimum amount of rubber used……..its expensive stuff, and even using the cheapest, but in my opinion one of the best available, even a 5.25 kilo tub of the medium grade rubber costs nearly £80.00, and so I don't like to muck a mould up and loose all that rubber….
anyway, I am now tired and so will mould them tomorrow.
more tomorrow night.

