Woodlife Posted January 12, 2011 Share Posted January 12, 2011 I was thinking of going two routes. Finding a good quality firebrick to line my forge, or learning how to make my own out of fireclay and sand/silica. These bricks are known to withstand up to 3,000 degrees F. My understanding of good quality firebricks can be made with minimal skill as long as the ingredients are available. But that doesn't help me as I couldn't find the method they were made. I don't know the best recipe of silica/fireclay and if that's the best way to even do it, and the method, just the ingredients. So that's why I'm posting this thread. I would be happy to purchase some of anyone has had good recommendations, however being the type of man I am, I love to make my own. It gives me a sense of accomplishment. Any thoughts or comment? Quote Link to comment Share on other sites More sharing options...
brian.pierson Posted January 12, 2011 Share Posted January 12, 2011 Woodlife, Additional thing for your list when making your own would be a kiln to fire the brick in. I would hit a local brick seller to see what they have or can get hold of. Small batch may be costly for them though. I understand the sense of accomplishment. To paraphrase commercials... Priceless. Brian Pierson Quote Link to comment Share on other sites More sharing options...
MattBower Posted January 13, 2011 Share Posted January 13, 2011 The sintering temperatures for refractory ceramics -- and that's what you're talking about here -- are extremely high and need to be sustained for many hours. You can't just build a forge out of unfired bricks, then fire it, because the exterior will never got hot enough to sinter. You'll have weak, crumbly, unfired clay on the exterior. For a 3000 degree brick you'd want better than 80% aluminum oxide, with a refractory clay binder, if you want to do it the old fashioned way. Quote Link to comment Share on other sites More sharing options...
Woodlife Posted January 13, 2011 Author Share Posted January 13, 2011 Thanks for the info. I found a video on youtube where this was done (not in a forge of course) with fire clary bricks. I'm curious why the Aluminum oxide. Doesn't Aluminum oxide and Iron oxide creat thermite? My curiosity has got me wondering if this has anything to do with it's mixture in the bricks. Quote Link to comment Share on other sites More sharing options...
MattBower Posted January 13, 2011 Share Posted January 13, 2011 I'm curious why the Aluminum oxide. Aluminum oxide is very refractory, has other good properties (like resistance to abrasion and chemical attack), and is reasonably inexpensive. Alumina also handles thermal shock better than crystalline silica (which is the other main ingredient in natural clays and most common refractories).Doesn't Aluminum oxide and Iron oxide creat thermite? My curiosity has got me wondering if this has anything to do with it's mixture in the bricks. No. Elemental aluminum plus iron oxide makes aluminum oxide, elemental iron, and heat -- lots and lots of heat. That's the thermite reaction.I found a video on youtube where this was done (not in a forge of course) with fire clary bricks. What was done? Got a link? Quote Link to comment Share on other sites More sharing options...
Sky Campbell (somewhere) Posted January 13, 2011 Share Posted January 13, 2011 Alumina not aluminum. I would consider castable. I have had great sucsess with kastolite 3,000 plus. It has good insulating value minimal silica and 80% alumina. I have heaters that are going on 15 years with kastolite. Second would be the old stand by mizzou it has no insulating value but you probably will back you brick or castable with fiber anyway. Mizzou is bomb proof and you wouldn't have to worry about flux eating it. I like to build forms and cast them like a large brick. You then build and fire in place. It's not sintering which is heat and compression but you will need to drive out water in combination. Chemically bound water in the castable. Heat up slow then after you see no more steam go for it as hot as you think you will be using. Quote Link to comment Share on other sites More sharing options...
MattBower Posted January 13, 2011 Share Posted January 13, 2011 Alumina is aluminum oxide, Al2O3, which is what I referenced above. +1 on the castable suggestion, or just buying commercial, dense firebrick rated to the temp you want. I've messed with natural clay liners enough to know that I don't want to mess with them anymore. (Not in a gas forge, anyway. As lining for a solid fuel forge they work well enough, although they're nowhere near as tough or long-lasting as a good castable. They could be, if you had a way to fire them properly in situ. But I've never heard of one.) But the OP likes the DIY approach, so I was trying to give him some input on that. Quote Link to comment Share on other sites More sharing options...
Sky Campbell (somewhere) Posted January 13, 2011 Share Posted January 13, 2011 Yes AL2O3 is aluminum oxide = alumina. Sorry Matt not trying to propagate misinformation. I also said heat to working temp I should say heat to working temp of castable for maximum strength and insulating value. I'll reread before I post next time. Quote Link to comment Share on other sites More sharing options...
MattBower Posted January 13, 2011 Share Posted January 13, 2011 Yes AL2O3 is aluminum oxide = alumina. Sorry Matt not trying to propagate misinformation. I also said heat to working temp I should say heat to working temp of castable for maximum strength and insulating value. I'll reread before I post next time. No worries. Quote Link to comment Share on other sites More sharing options...
Nakedanvil - Grant Sarver Posted January 13, 2011 Share Posted January 13, 2011 it has no insulating value Then it's what? A super-conductor?:blink: Quote Link to comment Share on other sites More sharing options...
MattBower Posted January 13, 2011 Share Posted January 13, 2011 Then it's what? A super-conductor? LOL. He may have exaggerated a little, Grant -- but Mizzou is a pretty sucky insulator. About 1/4 as good as 8# Kaowool at 2000 F. Quote Link to comment Share on other sites More sharing options...
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