Lost wax casting iron

I want to lost wax cast some small statuary in cast iron - this same
item I have previously cast in bronze using the following investment
casting plaster (which I still have a 50 lb bag of):
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I don't think that it'll take the higher temperature of cast iron
(1550 deg C pouring temp as opposed to about 1200 for the bronze) so
was considering using fine silica sand & sodium silicate both of which
I have to hand.
Once the bulk of the wax is steamed out of a plaster investment it is
then put in a burn out kiln to remove all traces of the wax and water,
and I would have to do the same with the sodium silicated sand, but
will this burn out the wax and leave a porous matrix as in the
investment plaster ? Obviously any wax trapped in the mould could be
potentially explosive when the iron enters so any informed opinions
would be appreciated.
AWEM
Reply to
Andrew Mawson
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What you're proposing rather negates the purpose of lost wax casting, why not invest in the correct ceramic coating product? The improvement in finish over your "sand" casting could well be worth it. BTW, have you actually inquired as to the maximum working temp of your casting plaster?
Tom
Reply to
Tom
Since what you are doing is a sand/silicate/CO2 mould, it ought to behave in the way that they have since time began...
Not an informed-by-experience opinion. Just a supposition that If we used to be able to do it on medium speed diesel crank cases with foam masters, you ought to be able to do it with wax masters.
Mark Rand (must remember to stay North of the Thames :-) RTFM
Reply to
Mark Rand
Too right! Preferably upwind too...
Regards, Tony
Reply to
Tony Jeffree
investment
opinions
casting,
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Tom,
The upper limit for the investment plaster is 1200 deg C and that's frankly pushing it. Above 700 deg C it begins to have problems with dissassociation but the metal tends to hold it in place. The ceramic shell slurries are available from people like Remet but in large quantity orders only. Hence proposing the use of a very fine (infact core) sand bound with sodium silicate, and my concern was the ability to burn out the residual wax.
AWEM
Reply to
Andrew Mawson
Got some drops we put in the dogs ears that remove wax, wonder if they will work. Can't see the dog being happy used as a test bed at 1200 degrees -- Regards,
John Stevenson Nottingham, England.
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Reply to
John Stevenson
Down Bronzo.... He's not a ferrous-shus hound.
Joules
Reply to
Joules Beech
That's what you might call making a dog's ear of it...
Regards, Tony
Reply to
Tony Jeffree
Platinum melts at 1774 deg C so you could look at the jewellery plat investments if you can find them in the quantities you want.
Reply to
Andy
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investment
opinions
Thanks for that Andy - I've decided to try to fine silica sand and sodium silicate route and keep my fingers crossed
AWEM
Reply to
Andrew Mawson

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