How to make your own high temperature refractory cement!
Today, i'd like to talk about high temperature refractory cement. What is refractory cement? well its basically a cement that is composed of some sort of high temperature ceramic or clay.
This special type of cement is used to make molds for metal pouring castings, kiln, forges, and gasifier hearths!
Yup, you heard me right I am going to mix up my own high temperature ceramic cement for the inner hearth piece of the gasifier.
The inner hearth needs to be made out of some sort of high temperature material since the inner gasifier zone can reach 1200 – 1500 deg. F . At these high temperatures most carbon and stainless steels oxidize very quickly. Basically the metal will rust very quickly and become too weak to hold the heavy fuel in the hopper.
I decided to make my own refractory because I have been having a very hard time located a local source for refractory cement. I located a website called backyardmetalcasting.com where this metal smith explains how to make your own forges, and kilns. I am going to use this same recipe to create my own cast-able refractory cement.
The basic recipe is:
The refractory mix is composed of Portland cement (1.5 parts), silica sand (2 parts), perlite (1.5 parts) and fireclay (2 parts). The first three components are mixed together thoroughly.- BACKYARDMETALCASTING.COM
I have already located a local supplier for the fire clay, silica, and portland cement.
Prices where as follows:
50lbs bad of fire clay is $22.00
50lbs bag of silica is $22.00
94lbs bag of portland cement was $8.00
and 10- 20 bucks for the perlite
so I can make about 150lbs of refractory for less then $60; this should be plenty of material for a few trial casting and for the hearth its self. I have ordred the fireclay and the silica from a local clay studio. Once I pickup my order I will begin building a trial mold for a test pour!