Stone Casting - sources of polystyrene

[Pete.]

Make sure you use a good mould release agent. Rubber and concrete stick together very well - especially if you don't want them to!

 

[gaz1]

id only use it for the internal

if you have a look at my cores as you might end up looking like this

http://www.mig-welding.co.uk/forum/threads/first-build-rocket-burner.45497/#post-778101

 

[puffernutter]

Perlite is about £20 for 100litres - if you substitute it for the gravel, it'll half the weight of the concrete.
It will also reduce the strength, but double the cement amount will counter that.
<edit gaz1 sort of beat me to it!>

My concern would be that I am relying on the fine sand (which apparently migrates to the outside) to give me the detail (fur etc.) and the use of perlite may end up on the outer surface and degrade the finish.

This is all new to me and these won't be cheap (getting to this point with the mould is £1400 investment!) So I'll want to be sure they'll stand the test of time in the respect of weather/frost etc.

I'll try Celotext first and see how much I'll use per casting and what weight reduction I get. I'll also do the next one without a plinth and see how it looks.

Cheers

Peter

 

[puffernutter]

Make sure you use a good mould release agent. Rubber and concrete stick together very well - especially if you don't want them to!

I'm being guided by the bloke who used to run the stone masons. The wood was treated to a mould oil, the rubber wasn't so we'll have to see what happens!

Wednesday night is going to be fun! Step 1, turn the full mould over!

Cheers

Peter

 

[gaz1]

stick a water bottle in it full of water when done pull it out before set