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lost pla/pattern castings ?

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PK:
So I'm a bit confused, what I've seen in this thread doesn't match my own experiences with lost <insert lost thing here> casting.
My attempts fell over at the burn out stage.  Heating the whole thing caused a thin shell to crack as the wax expanded, if that didn't happen then molten wax was forced into the refractory coating, if I used a big block of plaster then I could never get enough water out.
In the video's above the guy is using some magic powder that doesn't seem to need endless hours of baking to dry out and everything just works... 
Is this real?
Where can I get this magic powder?
PK

Joules:
BOLIVIA

vtsteam:
There are specialist plaster investments (good choice of term) and specialist waxes, etc. Then there are also specialized techniques developed long ago in bronze statuary founding. Mattinker where are you?

The wheel keeps getting reinvented. People forget, and then struggle to understand what was once known.

awemawson:
When I did a bit of lost wax casting years ago I got a sack of the high temperature version of Plaster of Paris but it was a pain to use - not sticking etc

In the end I reverted to using bone dry silver sand and Sodium Silicate cured with CO2. Wax was burnt out in a pottery kiln and I poured the metal while the mould was still glowing from the kiln.

I satisfactorily poured aluminium, brass, copper and iron - all that was about 12 years ago, but the door stop we still use today is a cast iron recumbent lion, modeled by my daughter in art classes at school in clay. I tool a Vynamould impression of it, poured wax into the cavity, cast the wax in sand and sodium silicate, burnt it out in the kiln, melted the iron in my induction furnace and that's the result. Poor thing had a hole drilled in him for a rod and knob to save me bending down !

picclock:
Hi

From just checking out the Alloyavenue.com site and one or two others it all seems quite doable and will be a very useful addition to my workshop.

I looked at an Australian video of a can forge and was amazed at what he achieved melting 1.7Kgs of cast iron in 20mins :-



So I thought I might up my aspirations and try to build a forge which could do this. The only part I cannot seem to source is the high temperature reflective coating which is applied directly to the ceramic wool. He uses zirconw. Searching the internet shows 3 possible alternates, Plistix, Metrikote and ITC-100. However these do not seem to be available in the UK, or indeed europe. Dont know if its one of these eu rule things.. .

If you have a furnace, what do you use as the high temperature liner ? 

At my current state of ignorance help needed.

Best regards

picclock
 

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