Introduction: Testing Fire Resistance: Alabaster, Putty, Sand, Cement

By Dural Metalurg

I tested fire resistance of some materials such as putty, alabaster (plaster), sand, cement. The purpose is to determine the best refractory for my new smelting furnace project. I decided to try different proportions of widespread materials which could be a good refractory for the walls of metal melting furnace.

Step 1: Making Samples

As a mould for tested materials, I used plastic cups.

I’ve made such samples:

1. Putty – 100%

2. Putty 50%/Sand 50%

3. Alabaster 50%/Sand 50%

4. Cement – 100%

5. Cement 50%/Sand 50%

6. Alabaster 33%/Sand 33%/Cement 33%

7. Alabaster 70%/Sand 30%

...and of course added some water to every sample.

As I know, a lot of such materials are used by home melters for crafting their foundries.

Samples were drying 1 day in a shadow and after that 2 days on the sun.

Step 2: Using Blowtorch

When they were enough dry I prepared gasoline blowlamp to test samples heat resistance.

Step 3: Heat Resistance Results

During the experiment all samples crashed. The best sample is №3 (alabaster 50%/sand 50%). This sample had the worst surface before blowlamp test. Though, it didn’t have the best look it got only small cracks. All other samples were highly damaged.

I’ve decided not to use these materials as refractories because in my opinion, their low temperature resistance won’t let to use them for the furnace walls for a long time.

In the next test I’ll use materials which should sustain much higher temperature.

I am planning to use fire clay (sustain 1600 °C (2912 F)), grog powder (sustain 1600 °C (2912 F)) and graphite dust (sustain more than 4000 °C (7232 F)).