Subject: Re: Binder for sand mold making.

From: [email-masked] (Fitch R. Williams)
Date: Fri, 13 Dec 1996 03:02:19 GMT

[email-masked] (Jens) wrote:

>[email-masked] (John Horvath) wrote:

>> form a large (10' by 10') sand-based casting mold.

>Whoa .... I wonder what size your furnace is ?????
>Are you building a replica of the Queen Mary in a 1:1 scale ?????
>At that size, any commercial casting or refractory supplier in your
>area will be more than glad to take your money.

>Jens

Bring cash.  Large bills are acceptable.

Fitch

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From: [email-masked] (Jens)
Date: Wed, 11 Dec 1996 12:01:39 -0800

Jens

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From: [email-masked] (Georgie Stanford)
Date: 14 Dec 1996 00:15:41 GMT

John Horvath ([email-masked]) wrote:
: I am looking for recommendations of a compound (preferably cheap and water-
: based) that will allow me to form a large (10' by 10') sand-based casting mold.
: 
: It needs to be workable and have a fairly thick consistency but it must
: set HARD when dry with minimal shrinkage.
: 
: Any techniques or tips in general on sand mold-making would be appreciated.

Two years ago I had a pair of sailboat hinges I was making out of bronze 
(actually high copper brass, but don't tell anybody. It was for my boat 
anyway) but the mold kept coming apart because the sand wouldn't hold 
together for the inch long 3/16 thick slot between the fingers of the 
female half. I spent all day experimenting until I found a combination of 
one cup builder's plaster to five cups of plain sand (not greensand) 
which held together well. I had to put in the water and mold it quickly 
'cause the plaster set, just like it would naturally. But it did real well.

I've never casted anything 10" by 10" and would be afraid to. Something 
that big would be really dangerous if the mold started spitting or 
exploded. I casted a bronze statuette once that was 8" by 2 1/2" but I 
used a lost wax investment mold burned out at 1100 degrees and then 
cooled to 900 degrees then dropped into a hole in the ground and packed 
in dry sand before pouring. But, using plaster cold it will BLOW UP 
just like greensand would with something that big!!!
 
I don't think that somebody should do this sort of thing unless they've 
been casting for a LONG time starting with lead at 400 degrees then 
aluminum at 800 degrees so they know what's going on. Brass and bronze 
are nothing to fool around with! 

Georgie

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From: Brian & Angie Vaughn <[email-masked]>
Date: Fri, 13 Dec 1996 02:24:43 -0500

> area will be more than glad to take your money.

 I was wondering if we all could see a picture of the monster melter.

Brian

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From: [email-masked] (John Horvath)
Date: 12 Dec 1996 04:17:23 GMT

Hello.

I am looking for recommendations of a compound (preferably cheap and water-
based) that will allow me to form a large (10' by 10') sand-based casting mold.

It needs to be workable and have a fairly thick consistency but it must
set HARD when dry with minimal shrinkage.

Any techniques or tips in general on sand mold-making would be appreciated.

Many thanks in advance.

John Horvath.

(E-mail: [email-masked] )