Long story short, I've baked my lid in the oven but I'm left with hard-packed and baked but not solid or rock-like sand. I used fireclay, play sand and water only, exactly as the book describes.
After re-reading the Gingery section on curing the refractory, it seems there might be another interpretation. It sounds like maybe "curing" only drives out the water and then "vitrifying" makes it really solid. Is that true? Or should I have essentially a millstone when I take it out of the oven?
Pictures here, the last two items are mainly about the lid.
It seems to me (not at all a physics genius) that you had a mixture of sand, clay and water. When you put it in your oven you are simply going to drive out the water. This should allow you to move onto the next step, which is to put this lid fearlessly on over your oven and fire it up. At that point the clay should fuse and the refractory should harden. That's my guess anyway.
Back a few years you could email Dave Gingery. Don't know anymore. Someone on this NG will know about this for sure.
Nice blow-by-blow description.
Grant Erw> Long story short, I've baked my lid in the oven but I'm left with
So, where did you finally find the fireclay at? Did you find it locally, or did you have to have it shipped to you?
I've got an old water heater tank, cut in half, and a squirrel cage blower that I want to experiment with. I have a bag of perlite and would like to try mixing it with fireclay in order to get a better R-value coating.
One of the problems I had with an experimental charcoal furnace I was playing with was being able to re-fuel it on the fly without disturbing the crucible. In the more permanent version I'd like to add a re-fueling port and an ash drain. The re-fueling port will just be a pipe of large enough diameter to allow briquettes to slide down, on a steep angle from the outside of the furnace running to the bottom of the interior. A removable pipe cap will keep heat from being exhausted out of it during operation.
The ash drain would require the fireclay lining of the bottom of the furnace to be thick enough to have the forced air inlet positioned below the bottom interior surface. Perpendicular to the air inlet port would be another hole going right down through the bottom of the furnace. A hinged, spring loaded lid would be mounted under the furnace to keep heat and forced air from escaping during operation. A grate made of welded re-bar would sit in the on top of the bottom lining to prevent coals from dropping through and clogging the air inlet.
I found it locally, but at $15/50lb. It was at a tile/masonry store about 30 minutes from here.
This is a good idea and I've been wondering about that. I also saw a picture online where the whole body of the furnace lifted up on a lever system, leaving a platform where the crucible sat and the fire underneath. Or something.
Could you please convert to HTML? XML seems to give IE 6 heartburn. When I click the link it asks me to download the file rather than opening it in the window as a normal HTML file. And when I open it from there it gets a style sheet error.
Tim
-- "That's for the courts to decide." - Homer Simpson Website @
Works fine for me, using Opera. M$ is not known for following standards, but, for trying to REMAKE them in their own image, so I suspect they are applying pressure by redefining how something works in IE. Regards Dave Mundt
I got the idea just from you mentioning it. However, I found after firing the furnace to set the fireclay, that propane would be a tad less messy. My inlet was big enough to use the Reil burner popular at the time.
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.