Author Topic: Furnace Refactory Linings  (Read 4635 times)

Offline Meldonmech

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Furnace Refactory Linings
« on: September 13, 2012, 03:17:11 AM »
Hi Guys
               My aluminium melting furnace is in desperate need of re lining, I originally used  a mix of Bentonite, Portland cement, Sand & Pearlite. I now realize that cement and bentonite break down at high temperatures.
                   My new lining must be able to melt Brass & Bronze, any advice on suitable refractories would be welcome.
The furnace is 12 inch O/D x 18 inch high, and melts about 1 litre.

         Cheers   David

Offline RotarySMP

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Re: Furnace Refactory Linings
« Reply #1 on: September 25, 2012, 05:09:07 AM »
I built my furnace to the design of Anon, the moderator of alloyavenue.com. He has a free e-book which describes the furnace build, and also includes the recipe for the mullite hot face.

http://www.alloyavenue.com/vb/showthread.php?2469-Foundry-Tutorial-Book

Mullite is koaline, allumna, and bentonite. I was able to puchase all three ingredients at a local pottery shop. Once fired, the resulting hot face seems completely immune to heat.

Here is my furnace build. I didn't let it dry long enough, and I fired it way to fast, and cracked it pretty badly, but it still works really well.

http://www.alloyavenue.com/vb/showthread.php?4948-How-long-does-it-take-a-furnace-hot-face-to-dry&highlight=rotarysmp

I have done a cast iron melt with it. I have done about alloy melts and this is what it looks like today. Looks like I need to mix up some more mullite and slip and do a patching session, and the next time it is hot, I should skim the silt alloy form the bottom.

Mark

Best regards, Meilleures salutations, Mit freundlichen Grüßen, Cu salutari
Mark
https://www.youtube.com/c/RotarySMP

Offline Meldonmech

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Re: Furnace Refactory Linings
« Reply #2 on: September 25, 2012, 07:46:21 AM »
Hi Mark,
             Thanks for your comments and for showing me your furnace and describing your experiences, very interesting. Did
you cast the saddle and tailstock for your lathe?  I only discovered and became a member of AlloyAvenue about a month ago, the references re. the casting of metals you gave were great, and there is so much info. I need to take on board.

              Cheers David

Offline RotarySMP

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Re: Furnace Refactory Linings
« Reply #3 on: September 25, 2012, 10:54:53 AM »
The lathe saddle is modified original. The cross slide is built up out of steel.  I started making up a pattern for a new cross slide, but go side tracked with other projects :)

That Mullite is not as easy as a cement based hard face, as it shrinks a fair bit when drying, and can'#t be hurried, but once fired it is only susceptable to mechanicial damage, not heat. As my bore dried a bit oval, and cracked during  the first (brutally fast) firing, I can only get my lifting tongs around the crucible in one alignment. At some stage I cracked lining some more being misaligned.
Best regards, Meilleures salutations, Mit freundlichen Grüßen, Cu salutari
Mark
https://www.youtube.com/c/RotarySMP