I managed to get my shit together today enough to make a batch of Starcrete, and now I'm waiting for the test pieces to cure.

Should be tomorrow I'll get some test results then.

I decided to use flour rather than cornstarch; in this application I dont think it'll make a huge difference.

Ingredients

1 Litre PVA

200g Sodium Bicarbonate

1.5 Kilo Plain Flour

1 Litre cold water

10 Litres Perlite

Mix together the Sodium Bicarbonate and a little water to make a paste, then add the glue and mix, then add the water to thin it out. It mixes better this way.

Then add the flour a little at a time until the paste reaches the consistency needed to glue the perlite together. I found I needed the whole bag of flour to make it gloopy enough, you could add more and make it stiffer but I dont think its necessary.

We shall see... ;-)

Take a cup of the stodgy mixture and slowly knead in 2 cups of perlite. This is fun, just like cocoa krispies.

This ratio of mixture makes a nice solid when compressed together.

Here I just grabbed a handful and moulded it into a ball with my fingers. It isnt messy now, the glue absorbs into the perlite and coats it, and it all sticks together really nicely.

I lined a dish with greaseproof paper and piled in some of the mixture.

The first one I just did with my hands, it works quite well but it wasnt very even. But it stays together when wet nicely and made a decent tile.

The next one I pressed down with a bit of wood. This crushes the perlite at the surface a bit and makes it smoother, I'm wondering if a press would work even better to produce even more solid bricks.

Shouldnt be hard to knock something up with some scrap plywood to push tiles out by the dozen.

Here's how tough the stuff is right after mixing. It performed exactly as I hoped it would.

When dry, that would be an artificial rock. :-D

This is using the test ratio of 2:1 Perlite / Starlite.