Hello fellow demi-gods of metal and fire! I'm new to this forum and to casting in general. I love all things diy crafting from laser engraving, to leather working, wood working, tool production, jewelry making, graphic design, silk screening, etc. I've been diving headfirst into blacksmithing and metal casting in the past two months like a maniac. I started out melting aluminum with a king of random style bucket forge with lump charcoal. But my life long creed of "there's gotta be a better way" kicked in and down the rabbit hole I went. I decided to switch to propane, and I was fortunate enough to source some free 4"x24"x24" sample slabs of aircrete from Aercon AAC (https://www.aerconaac.com/), and have built 5 different sized basic working forges out of them. I'm still updating them and working to make them more efficient. I also built my own propane burner based on ChiefChen's Candle V2 design (). It was pretty simple and cheap to build and works great. Most of my time so far has been in gathering and building the tools necessary to metal cast, and researching my brains out to learn from DIY'ers that have forged the path before me. so far I've successfully cast an aluminum sword with a green sand mold and wooden model that I carved myself, and a few silver-copper alloy rings for fun. But now I'm taking on a full on bronze casting project that I'm racing to get done before christmas for my mother in law. I'm hoping that I can glean from the experienced members of this forum to make more progress with less effort. Glad to be a part of the community!
Welcome Sillytrain, I'm not familiar with the aerated concrete product in foundry use. It appears to resemble Insulating Fire Brick but concrete (if it is Portland cement based) is generally not well regarded as a foundry furnace refractory material which are more typically alumina silicates. KOR was fond of using plaster of Paris which is also a poor choice of refractory material. I would strongly encourage you to use refractory materials specifically developed for high temperature furnaces in your furnace build. Foundry furnaces and forges have similarities but also differences. There will be some jargon (Tuyere, plinth, shank, etc) to learn but you come to the right place for advice and practical approaches to building a foundry furnace and foundry equipment. Coated ceramic wool furnaces are easy and inexpensive to build and there are many examples of these and others on this forum and plenty of first-hand advice available too. Best, Kelly
There are at least of a few people on Alloy Avenue that have used aerated concrete in their furnace, do a search over there on "Ytong" and you'll find a few examples. It seems like a very interesting material, light weight, highly insulating, easy to work and extremely fire resistant. In Europe, it's commonly used for non-load bearing walls but for reasons that escape me, it's not readily available in North America
"it's not readily available in North America".... you got that right! took me forever to find someone who makes it, and even then they don't sell small batches to hobby folks. But the lady was nice and they had a large shipment going to a town near me and so she marked a few slabs as samples if i was willing to drive to pick them up! I believe they use it for non load bearing walls because of it's insulating properties, cutting down on heating/cooling costs. I just got my tub of ceramic reflective refractory coating that i'm planning on lining the inside walls with. I'm not sure if that'll be enough to protect the aircrete from degrading where it's exposed to the open flame or if ill need to install a hotplate as well. We'll see how it holds up over time. I may wrap the outsides in ceramic blanket at some point since i ended up cutting them down to 2" thick walls which can get alittle toasty which means i'm losing efficiency.
I surfed around over there and 3D said it breaks down above 1200c (2192F) but he used a hotface. Another post said it breaks down at 1000c. There was a thread that claimed it became electrically conductive above 700c.....if true a bit concerning for a kiln/electric furnace. If 2300F ceramic wool lives well with a thin refractory hot face, I don't see why this would not, as long as it really retains it's mechanical properties at continuous 1200c exposure. Good castable refractory is 1700c. Cut your slabs into angled bricks and make a multi-sided furnace that approximates a cylinder with a tangential Tuyere, your burner will like that. ....oh, and read this front to back. http://www.alloyavenue.com/vb/showthread.php?2469-Foundry-Tutorial-Book Best, Kelly
I used ytong years ago to support a 300gallon aquarium. The germans loved to build houses out of that stuff. I didnt like how soft it is.
