"oogoo" cheap 2-part quick setting rubber polymer

Over at instructables some guy has come up with a cheap, fairly fast, fairly strong 2-part silicone rubber.

[www.instructables.com]

Basicaliy it's silicone bath sealant mixed with equal volumes of cornstarch (the cornstarch makes it more rigid and supplies the little bit of humidity that sets the bath sealant off very rapidly- normally it takes weeks).

I've had a quick play with it and it looks like a good way to create molds, and I would think you could extrude it, although it might be a bit viscous, it goes a bit thicker than toothpaste, it's clay like until it sets like a rubber.

It looks to me like a good bet for fabbing with, but there are challenges.

Probably would make great molds for casting strong, rigid stuff, and for seals, gaskets. Once set it can handle about 150C maybe.

had the same idea, but maybe with the silicone and corn starch(flour) paste being mixed at the last moment just be for extrusion, with a type of achiemedes screw, plunger syringe arangement, this could make positive molds which could be caked in ceramic powder, backed in a oven, the silicone, then being extracted, leaving a cavity to fill with molten aluminium, steel e.t.c.

experimentation would be needed

There are also some lower melting temp (180°C to 240°C) flexible polyamides under $10/lb that have a Shore hardness of D 40 or Shore A 80-90 similar to Macromelt used for low pressure injection molding that should work fine. What you don't use may just be remelted so there is minimal waste.

I've been using Silicone caulking as molds for years. All you need to do is mix a few drops of cheap acrylic art paint with a quarter of a tube of caulking and it hardens in minutes. There are a few other methods [www.myheap.com] but they are not nearly as easy. The paint allows you to see when you have it mixed evenly.

These are made with silicone caulk molds:


More pictures here [intrinsicallysublime.blogspot.com]

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