making a mold

[smolders]

I want to make a mold of a gabion I have scratch built, what sort of material should I be using to make the mold( the part I pout teh plaster into)? Where do I find it?

Thankyou

[Johnnie]

Have you tried Google?

Here's a Link to youtube anyway:

http://www.youtube.com/watch?v=jFfXT_Cjpuk

Might give you some hints

[Drumstick]

The cheapest way I use is buying silicone tubes which are often used for waterproofing things. It's around 3 pounds and there's enough to do several molds.

[Johnnie]

Try building the moulds with lego Drumstick. It looks rather easy on the video

Cheers!

[Comte Michel]

The way I always did it was to :

1. Build up a square of lego bricks big enough to hold the finished mould.

2. Half fill the lego box with plasticine.

3. Embed the item to be moulded half into the plasticine.

4. Coat the whole surface, lego, plasticine and master, with a thin layer of vaseline.

4. Carefully fill the lego box with RTV silicone and allow to set.

5. Turn upside down, remove the plasticine and rebuild the lego box. Coat with vaseline again.

6. Fill the other half with RTV silicone and allow to set.

7. Split the two halves, cut in pouring channels etc and voila, one mould.

[smolders]

This sounds like a great way to do things, but can you explain what RTV silicone is please?

[Cubster]

Do you warm the vaseline to make it easier to apply?

(I'm not planning to make a mould, I need to know for another pastime of mine.)

[Comte Michel]

Naughty Cubster Actually I used a homemade concoction of beeswax and turpentine, working in a chemistry lab at the time was a huge advantage. Vaseline seemed the most readily available substitute. Warming or thinning it with something so you can paint it on would help.

RTV is an acronym for Room Temperature Vulcanising (i.e. it hardens without heat) - the stuff we used was a two part silicone we got from a company in London called Tiranti - I have no idea if they still exist.

Ooh look http://www.tiranti.co.uk/ - seems they do

But you could equally well use the household stuff you get in tubes, just choose the runniest one available.