Fire clay: Getting pissed

Premier Refractory is what I use. They have since mergerd with Vesuvius Refractory Products. Do a search for Vesuvius Foundry or Refractory stuff. That failing, another well known company with equally good refractory materials is RENO refractories. They make some super plastic type ramable stuff. Easy to work with, no mixing, just, slice it up, and beat and form into place. Handles just like play dough would be. Lasts as long as castable types.

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You don't say where you are, so this is not likely to help you. But it might help someone sometime. Seattle Pottery sells all sorts of clays including fireclay. They also sell castable refractory. And they accept mail orders. But if you are in the Seattle area, you can get the castable refractory cheaper at a foundry supply house. The fire clay you can get at masonry places. Just look for a place that sells firebrick.

Dan

PhysicsGenius wrote in message news:... ...

So you want to go all the way back to the basics? Even grow the flour that you make the cake out of?

Well, OK, we're here to help! I was in a similar situation to you. No fire clay or insulating firebrick available at the local brick supply (but they did have fireplace firebrick). Of course Seattle Pottery has fire clay, but it would be nice to buy some locally, to avoid what you think would be excessive postage. Also, I was not, at the time, aware that there was a pottery supply store about 30 minutes away, but it does not really matter anyway, since I do not like to drive. This is too far.

So, I looked a while on the Internet, and I noticed some cool information about adobe, and "neo-tribal" furnace design. Now, here's something cool. Even the word is cool (neo-tribal). So, I shelved the idea until some resources come along (they always do). A short while later, I observed some Mexican laborers putting up a fence. It was quite interesting. There must have been four or five of them, but as soon as they dug 1 foot deep holes, all of them left except one. He stayed behind for the next few hours poking the ground with this heavy iron rod which was sharp at the end. Very interesting. Eventually, the other laborers dug the fence post holes deeper now that the soil had been broken up. This seemed very interesting, so I went to the nearest nursery (where the Mexicans were putting up the fence), and inquired about the affair with the iron rod. The helpful worker at the nursery told me that the soil within a few miles radius is nice for a few inches, then it is rock hard adobe below. Very interesting. This reminded me of the stuff I saw about the neo-tribal furnace design. I did not realize adobe could be so strong. I shelved the knowledge until it came time that I was asked to help dig a deep hole in that neighborhood. I remembered my observation, and brought a pick hammer and a bucket. Sure enough, there was hard adobe clay under the first foot of topsoil. I saved it in the bucket, just like I save the little tidbits of knowledge and information that so serendipitously come our way.

Some time went by, and I was asked to trim some trees. One of the trees is an apple tree, and I saved the branches that I trimmed. I then used them to BBQ meat, since I read somewhere on the Internet that they produce good smoke flavor. Of course, because of the neo-tribal article I read earlier, I saved the ashes in a bag.

Some time later, I was asked to demolish a redwood deck. Since the lumber was pretty rotted, I was allowed to keep some of it. I knew what to do with it after I poured some concrete footings. Since the decking was to be replaced with screws, I also kept some nails. Of course, I saved a small amount of concrete powder after putting in the footings. Using the nails (banged them straight with an old hammer I found in the street), I put together adobe brick molds. Then, I mixed the wood ashes from the BBQ, the adobe from the holes, the concrete left over from the deck footings, and a little water. I packed some of this into the brick molds, and I patted some out into rectangular patties, and laid it out on the old deck wood. I placed these in the sun for a few weeks.

Unfortunately, the thick brick cracked. The thinner ones held up fine, but were physically weak. But, they stood up to heat very well, even to an acetylene torch, which caused them go glow mightily in the flamed spot. They stood up to brazing duty and even to a small copper melting job with a Reil-type burner. Very light, low thermal mass, good insulating capability.

If you have a lot of time on your hands, you could give this a try. Actually, I am very busy, and I don't have a lot of time on my hands. But I am not in a rush. A lot of nice things float your way if you are not in a rush. Patience and constant directed investigation can make up for a lacking money problem.

I have had very good results with a sandy clay mixed with vermiculite. Too bad the piece broke after an aluminum melt (I was pulling out the stick-in aluminum) because it's so soft unfired (not having a kiln, the only part I can torch is the inside where the heat goes).

BTW, the clay has a story.. it started out as sand I used to cover charcoal after I toasted some up (see my webpage under casting), well running out of straight sand I had to use foundry sand.. so all that got mixed together along with some ash and fine charcoal. Eventually I sifted it out and sorted by density... i.e.. flotation seperation. Got a good bit of nice and fine charcoal, but the heart of this story is the stuff that was floating in the water. So I let the water sit and sit and SIT, and siphoned off water as it settled, and eventually dried it out into a soft lump of clay about 1/2 the volume of a gallon bucket of ice cream... Before I made the above-mentioned device, I kneaded a bunch of vermiculite, maybe a bucketful (1gal) worth, which after kneading and some extra water brought the volume up to about 3/4 gallon.. lotta air in that vermiculite! ;)

Tim

-- "That's for the courts to decide." - Homer Simpson Website @

The fun is that I'll have a lathe, and you'll still be looking for a bag of clay.

Now I think producing a domestic capacity to cast brass to my own designs is a great goal, but it's a lousy long-winded way to acquire machine tools. If you ever _do_ it, then I take my hat off to you, as a more honourable person than I am. But chances are that one day we'll end up on the same bench in the old folk's park, and I'll have spent a lot more time turning stuff than you got to do.

I'm no fireclay expert (although I did spend last week helping Jarkman work on his new forge). AIUI, there are many grades and heat ranges. But a reasonable start in the UK is to find "Purimachos" fireclays from almost any builder's merchant, where they're used for installing coal fireplaces.

-- Die Gotterspammerung - Junkmail of the Gods

You have a point and if "turning stuff" is your goal, go ahead. That's not really my goal, though.

As per my original example of the cake mix: If "eating stuff" is what you want, using cake mix makes sense to save time. But if you want the fun and uniqueness of doing it yourself, cake mix doesn't provide that.

Going in to this project, I promised myself I wouldn't feel guilty if I didn't finish it because "ending up with a machine shop" isn't the point. I've already learned a bunch and all I have so far is a couple molds--it's totally worth the $20 I've spent so far.

But why not buy in the machine shop, and re-work your goal as casting your own telescope / statuary / whatever ?

-- Die Gotterspammerung - Junkmail of the Gods

Because that costs money. Even if I had that much, it would be spending money on something I didn't know if I'd ever finish. This way I spend a small amount and don't feel guilty if I drop it. If I finish it and use the lathe, maybe I'll be able/willing to justify purchasing a commercial unit. But if, right now, I dropped $2000 on everything I needed and then never actually produced anything, I'd kick myself.