This is the last part of Big Smelter project. I’ll finish this metal melting furnace by making refractory lining, drying, firing and finally testing. I can say that it’s my longest DIY project. It took me little more than 5 weeks to finish this work. I tested it by melting aluminum, brass and copper. The furnace passed all tests and got just minor damages.

Step 1: The Refractory Mixture Formula

The final refractory mixture formula is 50% of grog, 43% of fire clay and 7% of graphite dust. We should mix all the components and add some water. A lot of people during making refractories recommend to use less water. I don’t agree with that. In my opinion, it’s important to use a lot of water (may be the same quantity as is used for making concrete). I tried to use a small amount of water during lining the lid and it worked very bad.

Step 2: Lining

Lining the furnace with the refractory mixture.

Step 3: Drying

The next stage is drying. I’ve decided to use a bulb as a source of heat. The temperature outside was from -5 °C to +8 °C (from 23 °F to 46 °F), and rain, snow from time to time. Therefore, it wasn’t easy and quickly to dry 50 kg (110lbs) of refractory material.

Step 4: Firing

When furnace lost most moisture it was a time to start firing. I made it very slowly. In the beginning I even didn’t blow the air inside. And after some time I could start blowing the air. During the final test the furnace was working during an hour. That’s usually enough time to melt copper.

Step 5: Conclusion

I’m satisfied with the result. Now my home foundry allows me to melt and cast metals when I need it and I don’t need to fix the furnace after every melting.

If this information was interesting for you, please watch the first and the second part here:

Part 1 - Smelting Furnace. Project "Big Smelter". Making Outer Skin.

Part 2 - Big Smelter Project. Making the Lid

<p><em>&quot;The temperature outside was from -5 &deg;C to +8 &deg;C (from 23 &deg;F to 46 &deg;F), and rain, snow from time to time.&quot;</em></p><p>I have to admit I'm being spoiled living in Florida, today it's about 76F (24C) and clear, sunny skies. When I lived up north in Illinois, I used to get so depressed looking up at overcast gray skies for weeks on end during winters.</p><p>Anyway, it looks like you are really making some serious advances in your metalcasting efforts, good for you.</p>
<p>Thanks :) It's cool to be able to go swimming in the winter. I can imagine what is Florida. It's much easier to dry a furnace, yeah...? :) Though I should say that once I was in Alaska, Anchorage. Comparing to this US region Ukraine is very warm. Anyway, Alaska is a very beautiful state. I was like in some fairytale. I'm sure that everybody who lives on plains feel the same. We have mountins in our western regions and there I feel myself the same, like on the other planet. Nevertheless, I'm glad that there are no extreme temperatures, or earthquakes, or tornado, or volcanic eruption and so on... And in the same time, nobody likes temperature below zero. :)</p>

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