1/3rd scale SAFS MaK scratchbuild, got a question

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grabula
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Joined: Wed Oct 07, 2009 7:01 am

1/3rd scale SAFS MaK scratchbuild, got a question

Post by grabula » Sat Feb 27, 2016 10:26 pm

I located a giant plastic egg, like the small kind that split open for easter. It's about a foot long together and would make a sweet large scale safs suit. However, I want to be able to use it multiple times abd I'm trying to figure out how to use it as a mold but I'm not sure what the best material would be to use as the 'cast'. I'm considering going all out on this thing, some lighting, movable parts and so on. This means I need to find a durable material that's still relatively easy to work with.

ajmadison
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Post by ajmadison » Mon Feb 29, 2016 9:33 pm

Without sounding like a cranky naysayer, but an egg shape one foot long, you're at the very limits of high resolution model making reproduction. Vac-forms are routinely at these dimensions, but the level of detail with those are limited and their subject matter is often long and skinny, e.g. ships or aircraft.

Room Temperature Vulcanization (RTV) mold making is priced by volume, so at one foot you're likely to be spending big money for enough mold material to cover your project. There are tricks to reducing the needed volume of RTV so it only covers the parts of your prototype that need it, but this requires a lot of planning and advanced methods of creating a support system for the mold as you pour it.

If you really want to make multiple copies with different variations, you may want to plan around the egg shape as the base, starting with multiple "eggs" with reproduced (and smaller) details attached to them.

Admittedly, I am only picturing your project in my head, and crucial aspects that would reduce total volume would be obvious with a picture. Hope my advice helps guide you to a solution that helps you create the models you want without having to scratch build every last bit of them.

grabula
Posts: 10
Joined: Wed Oct 07, 2009 7:01 am

Post by grabula » Mon Feb 29, 2016 10:14 pm

Thanks for the reply. Since this us a scratchbuild I'm not concerned about detail to be honest. My thought was, the plastic egg acts as a mold, I line or fill that egg with a material I can work later to get the results I want. For example I've been looking at that expanding insulation foam as a filler, but never having worked with it I don't know how durable or is long term.

In effect the egg acts as a mold for the base material and I use that to build up my details and so on.

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