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Post by pinhead on Oct 19, 2011 0:16:53 GMT -8
I got a few buckets of furnace cement and have a few bags of vermiculite. I want to build an insulative burn chamber cast using these two materials. The furnace cement withstands up to 2700°F. So how would I go about casting this as one piece? The casting would be about 1.5" thick... I've watched videos of using a vibrating table to make the cement settle into all of the nooks and crannies of the mold and to reduce air bubbles. But am I correct to assume that vibrating the mix would make the vermiculite float to the top of the mold? |
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Post by pinhead on Oct 21, 2011 0:02:08 GMT -8
I was watching RMH "workshop" videos on Youtube and found THIS one. I mixed the furnace cement, some water, and vermiculite like they showed at about 4:03 in the video. I'll let it dry for a couple of days and see how it holds up. |
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Post by pinhead on Oct 21, 2011 16:27:47 GMT -8
The "mold" dried over night and firmed up really well. I'm going to let it sit for the rest of today and probably fire it tomorrow. Does anyone have any suggestions as to how quickly I should heat the mold? I suspect the vermiculite will be holding quite a bit of water and wonder if heating the entire mold above the boiling point will force the vermiculite to release the water in the form of steam and blow parts out...
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Post by pinhead on Oct 24, 2011 15:05:36 GMT -8
I fired the contraption this morning and the mixture seems to be working well and insulates better than expected. Heat-up takes slightly longer than the previous sheet metal/vermiculite design but that is to be expected. It steamed a lot more than I thought it would, but not excessively so. There weren't any pops or noises that I would expect from a "blow out" caused by a steam pocket. It still feels good and solid and is holding together well.
The heat riser is sheet metal insulated with vermiculite; I've only cast the burn chamber thus far.
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Post by stovol on Oct 25, 2011 11:29:18 GMT -8
i'd love to see some pics of the cast burn chamber pinhead... did you fire it really hot or go slow with it the first few times..? i did a paper fire.. then next night 30 min.. next night an hour... then a three hour burn..
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Post by pinhead on Oct 25, 2011 16:15:54 GMT -8
I burned for about an hour with paper. Once it stopped steaming I added some wood to get it to start steaming again. I added more wood each time it quit steaming until it was loaded to full capacity. Burned it like that for probably an hour when I ran out of wood.
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