jdelaney44

Well, I got enough of it! That bag from Home Depot has to be two bushels! LOL! Thanks, -jd

Ordering polystyrene beads at: http://www.foamerica.com/default.asp Matt's telling me the Perlite has fluxes that will lower the melting point of the compound. Totally makes sense to me. I still want to give the perlite a try, but given he knows the beads work, I want to do that too so I get to the best mix sooner than later. Thanks Matt! -jd

It's a bust. I think the oil in the seeds got me. OK, well now we know seeds are not an easy fix. Moving on ... More thoughts on the subject here - http://redwagonforge...1/its-bust.html Note to self, use link from blogger in the insert picture URL box. Using the Flickr links doesn't seem to work.

Firing the first sample today. It was dry. I cut it in half with a back saw. It cracked straight through about half way into the cut. The center is totally dry. The other two samples had the same resonance to them when I tapped them. So I am sure they are all equally dry. Firing program Ramp at 150 F / hr to 300 F Hold for 2 hours Ramp at 1000 F / Hr to 2300 F* - 2300 F is about Cone 9 Hold for 2 hours *Getting 1000 F / hr past about 1500 with this kiln is impossible. I'll be lucky to get 300. I'm also going to have to monitor the breaker box. This is the first high fire cycle I've done at this house. I'm using a 10 GA copper cable that is tapped directly into a 30 A breaker. Should be OK. The max draw on the kiln is 1800 watts. That's like running two hair dryers at full heat or every light bulb in the house. Well, we should have burning seeds before too long! http://redwagonforge...mple-today.html

Did some testing on the seeds. Trying to figure out how hot I should go for the next hold cycle to drive off the remaining water. Here's what I got. 300 for an hour - all the seeds brown a little, no real smell 350 - almost immediately the cracked corn pops, everything else browns pretty dark, smells toasted 400 - some of the other seeds in the mix pop like the pop corn did, everything else gets a lot darker, some of the loose hulls start to char 450 - some more seeds pop, everything starts to char Note: The millet did not pop at all and it was the last to char badly. So the answer is 300 F for the max hold temp to drive off the water. If anything in the mix pops, I'm screwed, the whole thing will start to crumble from the inside out. I'm going to try to bisque one of these Saturday using slow ramp to 300 and a good 2 - 3 hour soak before taking it up to a good bisque temp for the EPK.

Found an interesting link to an induction furnace project. The guy seems to be a bonafide engineer and explains some of his theories to the point where I get it. It would take me days to figure out the math & such. He's in flight. Hope he keeps going and finishes it. http://hildstrom.com/projects/inductionfoundry/index.html

Matt, good suggestion. Thought about that actually. You can buy the beads in bulk as bean bag stuffing from Uline. Or you can just buy the un-expanded beads. They plump up nicely with a little steam if I recall from a plastics class I took years ago. Getting them in small amounts is probably the harder part. Phil, also a good suggestion. Makes total sense. The sawdust is sounding easier and easier unless this stuff performs well enough to be worth the process. Latest post - http://redwagonforge.blogspot.com/2011/11/approaching-dry.html No big news. Couple more pics. They are just getting drier and I'm starting to be able to tell based on color changes. The "oldest" one is clearly whiter than the other two. One thing I didn't say in the blog, it's also starting to sound more like dry clay. It's starting to get a little "ring" to it. The others are thumpy like an old apple.

Frosty, I just read your post again. We are in total agreement. Thanks for getting me thinking more clearly. Phil, thanks for the tip on the grog. My friend Aaron said the same thing as soon as he saw the stuff. He want's me to keep going on this as he may have some artistic application for the concept. Everyone else, thanks for the comments & interest. It helps in overcoming a big failure like this one. Man I was bummed!

Had the slabs in the kiln at 160 F for ~15 - 16 hours Saturday and ~11 hours Sunday at 160 F. Then took them up to 190 F for about ~5 hours. So far no cracks in the one I can see which is the oldest one. Started the kiln again this morning at 09:55 with a 190 F setting. Also posting here - http://redwagonforge.blogspot.com/ Frosty, I wanted to make sure I understood what you were saying about bisque-ing. Yes, I'm pretty familiar with bisque-ing. Although I probably can't spell it. The 3 - 4 clays I have used in the past are usually bisqued in the 1300 - 1900 F range. I have put green ware in that was too green to have it explode around 900 - 1000. I was actually trying to bisque the trial piece. Were you saying that I needed to let it "soak" at ~400 - 500? Recommendations vary with respect to soak temps & time to drive off moisture. My friend Aaron who is a potter gets really agressive with it. But he throws really thin walls and I think he is used to short dry times and fewer issues with thick clay bodies, that are too wet like this. I also did some more reading. The book "Hands In Clay" give a good overall treatment of the firing process and the stages. Apparently there is a "quartz" transition range around 441 F. This fits with your gut feel of a soak in the 400 - 500 F range. This is where the impure silicates begin to change out of a crystalline state. In plastics I learned this as the "glass transition temperature". It was were the cross linkages in thermo plastics started to break apart. At that point the plastic started to become flexible. "Hands In Clay" also discussed fluxes. I'm convinced I need one or more fluxes. There is a % of fluxing material in the EPK and Zircopax plus. More math here I guess. Another observation with respect to porosity. I said the carbon saturated the matrix above just in passing. When I enlarged the pictures I could see that it really did. That tells me that this mix is WAY more porous that I ever imagined. At the molecular level the combustion by products are oozing everywhere. Thinking that through, maybe I need another soak time at around 350 or where ever that seed carburizes at. Frosty made the good point about the oil in the seed. That may carburize around 300 or so. Well anyway, this IS too much, but I do want to see what it takes to get the seeds to work if I can. If I can get one bisqued and fully fired at cone 10 it'll be interesting to see if the big pockets insulate well.

Oh, regarding temps & old kiln designs. I think as that PDF points out, wood fired kilns can get very hot. As I understand it, the matter is getting energy into the kiln at a rate that exceeds how fast it's escaping. I've read about several wood fired kilns where the ash from the wood burning in the early stages of the firing becomes the glaze. These firings can take a couple days and constant tending by a small team.

Link to the pictures. Sorry. The photo upload features on this site suck! 1. 2. 3.

Well if I don't want a wet mix, then I am WAY off. Ok, well, I am where I am. <a href=" title="IMG_3818 by Total Slack 44, on Flickr"><img src="http://farm7.static.flickr.com/6215/6313572715_8250ffb24f.jpg" width="500" height="333" alt="IMG_3818"></a> IMG_3798 by Total Slack 44, on Flickr IMG_3802 by Total Slack 44, on Flickr 1.) These are some of the larger chunks. 2.) The whole pile in the kiln after I was picking through it. It was a more consolidated pile 3.) Some larger chuncks with the lens cap for a sense of scale So, I've been drying the slabs. One I put in the kiln last weekend for about 16 hours at 150 degrees F. No problems. So I've got the other two in there now. I put the first one in the kitchen oven at 170 this evening. There's still some moisture coming off it. I can feel it and smell it a little. Not much but it's not totally dry. So ... that's going to take some time. No sprouts! I got sprouts in the dark of the garage on the first batch. So either re-mixing it or letting it bake in the sun suspended that process. It was pretty warm last week. Not sure if cooking the first slab at 150 killed the seeds or not. That would not seem to he hot enough, but maybe. I think the hold might be better around 300. I noticed on the last round that the seeds started to char at 350. The carbon you see above formed at 500. When I let it soak at 500, it was totally black. The white material was on the outside at around 900 - 1000. The black material was in the core of the pile. When I shut it down, the carbon, or whatever was still burning. There was flame coming out of the pile like you get with charcoal. That's pretty much what I had at that point. Charcoal mixed with clay. Your comment about the oil is an interesting thing. That oil might plasticize before it burns. Not sure what that does for me though. Grog / silica sand. Yes. I feel I need a larger aggregate in there some place. The next couple of tries are going to be small batches. I don't know WHAT I was thinking going for a full batch all at once. Anyway, I'm going to stick with this for a bit before I cave and just buy the castable.

Posting here too - http://redwagonforge.blogspot.com/ Can anyone tell me the trick to easily posting images here?

Looks like a nice build. Well done. -jd

That PDF is pretty cool. Thanks for sharing! Failure is mine! Arrrgh! I did a test firing today on a small piece. It was hand built so it wasn't as dense as the panels that are still drying. As is past 500 degrees it was a cracked pile of black stuff. The clay had shrunk in past the seeds. Black, charred seeds were on the surface. The whole thing was black. I looked like a pile of ash. At about 900 it turned white and I had some hope it might vitrify into something eventually. I increased the target to cone 7. At about 1250 it caved in on itself. It looks like a gross flaky gray pastery. You could see flames from the organics continuing flame off. I shut it down at this point. Why waste the power? Oh, and man it reeked. Fennel does not burn nicely. Maybe THAT's why sawdust is the normal solution. It's cooling. There is a red hot core still. I'm holding out hope that has consolidated into something. Well, this should be interesting ... I'm not even going to begin to speculate until I can see it up close.

Failure is mine! Arrrgh! I did a test firing today on a small piece. It was hand built so it wasn't as dense as the panels that are still drying. As is past 500 degrees it was a cracked pile of black stuff. The clay had shrunk in past the seeds. Black, charred seeds were on the surface. The whole thing was black. I looked like a pile of ash. At about 900 it turned white and I had some hope it might vitrify into something eventually. I increased the target to cone 7. At about 1250 it caved in on it self. It looks like a gross flaky gray pastery. You could see flames from the organics continuing flame off. I shut it down at this point. Why waste the power? Oh, and man it reeked. Fennel does not burn nicely. Maybe THAT's why sawdust is the normal solution. It's cooling. There is a red hot core still. I'm holding out hope that has consolidated into something. Well, this should be interesting ... I'm not even going to begin to speculate until I can see it up close.

Thanks for the comments! Today I broke up the slabs and increased the seed content. I added about double the seed that was in there. The slabs have been re-cast and are drying again. This time I over filled the forms a bit, put a piece of plywood over them and beat them with a 5 lb. compo cast type hammer to consolidate it better. Then I screeded it off. Pix to follow. The millet had begun to sprout by this morning! LOL! Just the surface. The deep stuff was not doing anything. This was supposed to be hulled millet. I guess that's not enough to stop it from germinating. It was growing some nice mold too. Interesting. EPK is EP Kaolin. I'm just figuring all this out so this is what I know. Kaolins are clays that seem to be found in areas where sedimentary coastal ocean floor has pushed up. I found three major formation here in the U.S. and apparently there are several in China as well. The EP Kaolin is produced by Edgar Minerals in Florida. It has the highest content of Aluminum Oxide that I have found available commercially. It comes in a 50 lb. bag. It's very fine from ball milling. If you want "fire clay" this is the best I think you can find. It's cheap too. Like $7 - $8 a 50 lb. bag. The other two Kaolin sites I found are in Kentucky and close to where I live in Amador County west of Sacramento CA. However, those sites are a little lower in aluminum oxide content. With regard to the firing of a non-setting ceramic like this. Yes, if you were firing it in-situ there would be all those problems. I fortunately have an electric ceramics kiln. I've been giving this some thought. How does one without a kiln pull this off? Not sure yet. First I want to see if it works. If it works, then maybe it's worth exploring some options. Possible solution: A one time kiln out of mud and straw is a centuries old approach to firing ceramics. If one has already built a workable burner or three, it seems to me that a one time mud & straw kiln is possible. Maybe even throw in some wire mesh for good measure. If it's in the middle of the mix, it's not going to get hot enough to totally lose it's tensile strength. If one wants to get really old school you could fire it with wood.

So, even with pretty crappy fire brick I was able to get it hot and get some metal hot. You can see the hot burner tip through the hole here too. This was after probably 20 minutes running at between 10 and 20 PSI. I did get a few flame outs when I choked down the opening too much and the back pressure built up. My current thinking it that a chimney is going to be a good idea. Of course this will have to be balanced with the material opening. I'm sure this is more of an art than a science.

I've decided to give a go with some EP kaolin, aluminum oxide, zirconium silicate, sawdust, and millet seed. The blend was about this by calculations: 32 lbs EPK 13 lbs aluminum oxide 5 pounds zirconium silicate ~ 1 pound saw dust ~ 10 pounds millet I ran short of Aluminum Oxide so I substituted zirconium silicate for the balance. The sawdust & millet was intended to be about 20% by volume. This along with whatever air gets trapped in the mix will provide gaps that should create the insulation properties once the compound is dried & fired. Frankly I am now feeling like I should have gone to 50% on the sawdust & millet. I want to let these panels dry and fire them to see how they look compared the the walls of my kiln. The dry mix before dry blending The mix after water & some machine mixing with a 1/2 inch eletric drill and a mud mixing attachment Here's what it looked like after being pressed in the mold It's drying now. The shrinkage has been about 3/16 in. in 24 hours. That was enough to get it out of the forms. Total shrinkage after firing is supposed to be 11% - 12%. Oh, dry any flat clay item on something like Hardie board or drywall. These materials tend to pull water out of the bottom of the piece and continue to dissipate the water. If you don't use something like that, the top dries way faster than the bottom and it starts to cup. Hopefully the sawdust will keep it from cracking. Once it's dry it goes in the kiln to be fired as close to cone 10 as I can get it. That will burn out the sawdust and the millet. If all works according to what I've been able to research, this will yield an insulating ceramic panel. Actually, it will probably have to go into the kiln for a day or so at 180 - 200 degrees until the water stops coming off it. The last thing you want in clay as it approached 1000 degrees is water. I've had this happen before and lost the piece with the water in it and several pieces next to it. I have no idea if this is going to work for me as it has for others before me. We shall see. Keep you posted.

I've decided to give a go with some EP kaolin, aluminum oxide, zirconium silicate, sawdust, and millet seed. The blend was about this by calculations: 32 lbs EPK 13 lbs aluminum oxide 5 pounds zirconium silicate ~ 1 pound saw dust ~ 10 pounds millet I ran short of Aluminum Oxide so I substituted zirconium silicate for the balance. The sawdust & millet was intended to be about 20% by volume. This along with whatever air gets trapped in the mix will provide gaps that should create the insulation properties once the compound is dried & fired. Frankly I am now feeling like I should have gone to 50% on the sawdust & millet. I want to let these panels dry and fire them to see how they look compared the the walls of my kiln. The dry mix before dry blending The mix after water & some machine mixing with a 1/2 inch eletric drill and a mud mixing attachment Here's what it looked like after being pressed in the mold It's drying now. The shrinkage has been about 3/16 in. in 24 hours. That was enough to get it out of the forms. Total shrinkage after firing is supposed to be 11% - 12%. Oh, dry any flat clay item on something like Hardie board or drywall. These materials tend to pull water out of the bottom of the piece and continue to dissipate the water. If you don't use something like that, the top dries way faster than the bottom and it starts to cup. Hopefully the sawdust will keep it from cracking. Once it's dry it goes in the kiln to be fired as close to cone 10 as I can get it. That will burn out the sawdust and the millet. If all works according to what I've been able to research, this will yield an insulating ceramic panel. Actually, it will probably have to go into the kiln for a day or so at 180 - 200 degrees until the water stops coming off it. The last thing you want in clay as it approached 1000 degrees is water. I've had this happen before and lost the piece with the water in it and several pieces next to it. I have no idea if this is going to work for me as it has for others before me. We shall see. Keep you posted.

John, love that cart. That could be adapted to my milling machines & my lathe. Best, John D.

Well, here's the burner pic. Trying to get the hang of the upload here. -jd

Phil, Thanks for the tip. Yep. The fire brick is a calculated risk. I figure worst case I bust it out and replace it with cast panels. Or maybe just the outer layer. So I have something harder on the inside. I'm figuring I'm going to screw up the first one pretty big. So, I wanted to do that as cheaply as possible. Best, John

A big thanks to everyone here and other places who have put out information about their builds and designs. Due to this I've been able to build two successful propane burners and am moving along to completing my first forge. I'm 50 now and have been wanting to do this since I first experienced black smithing at McCormick Jr. High School in Cheyenne Wyoming. Lot's of "reasons" why, why not. No matter. I'm here and it's becoming a reality thanks in a big way to you folks. I'm documenting my forge build here for now: http://redwagonforge.blogspot.com/ Time permitting I'll get some stuff up here too. Best, John