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Home made high temp castable refractory


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I don't understand what this means?

Thanks


Portland cures by absorbing water into the molecule. At about 500F and hotter, the water is driven off, making the portland no longer bind anything together. This means that if portland is used to bind your castable at high temperatures the castable disintegrates.

An alternative that is cheap, but much less easy to make, is to use high fire clay and grog. Grog is simply smashed vitrified clay. Vitrification is heating till the clay recrystallizes. This will require a ceramics kiln of some sort as the time at temperature is in hours. Kaolin and porcelain are good choices for this process.

Using a lesser insulation with the understanding that it has a limited life is reasonable too.

Phil
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Thank you for the schooling. Does this mean that some of the Portland would become airborne, and would the PPM be significant? I dabble in ceramics, take classes from community college. I will have to run this by the instructor see if he can help come up with a good castable refractory .

Very informative thank you
Kenny O

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Definately leave out the portland.
Use a high temp clay, I prefer Kaolin, which runs $10-$15 for 50lb, use silica sand or grog, approx 20lbs grog/sand to 50lb of clay, to reduce shrinkage and add strength and if you want it to be insilated add in some foam beads, bean bag chair filling works good, add as much foam as your mix will allow and still hold together, add water very little at a time and mix well. Then do 1/4"-1/2" hot face, [clay mix with no foam in it].
Let it dry slow and then fire it slowly, if you fire it too fast it will crumble.
It will handle 3000F with no problem.
I use this mix for my forges and casting furnaces.

welder19

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This site was posted as part of a reply in the home made hand crank blower thread and down the page is the Gingery book on making a melting furnace. As I recall there was a refractory recipe. http://www.amazon.co...n/dp/0917914600

Frosty the Lucky.

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Like Phil, and Frosty, I have several of David Gingery's Books. The centrifugal fan book is very good. I have built several fans using this book. Home brew furnace refractory recipes can be found in the charcoal foundry book.

Larry

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Thank you very much for the input guys,the recipe I was looking at came from the backyard casting site, the site has a wealth of info but, the recipe calls for portland cement, thus the crumble effect.would a crushed old toilet work for grog ?
I have fire clay, sand, and, pearlite for insulation,the hot layer sounds like a good idea. Would 72 hours cure time be adequate before a multi stage slow firing ?
O.H. by the way 2 dog, are you one of the 2 dogs over the hill from K falls? If so Ive seen some of your work ..Good of course.
HAMMER HAPPY DUDES Clifford B)

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Thank you very much for the input guys,the recipe I was looking at came from the backyard casting site, the site has a wealth of info but, the recipe calls for portland cement, thus the crumble effect.would a crushed old toilet work for grog ?
I have fire clay, sand, and, pearlite for insulation,the hot layer sounds like a good idea. Would 72 hours cure time be adequate before a multi stage slow firing ?
O.H. by the way 2 dog, are you one of the 2 dogs over the hill from K falls? If so Ive seen some of your work ..Good of course.
HAMMER HAPPY DUDES Clifford B)


Any high fire clay that is being disposed of will work. Toilet is prime due to the quantity from one go, but you have to smash it down quite far, below 1/4 inch screen for good results, sand-like is better. In truth old china is somewhat easier, but hard to get stuff you feel comfortable destroying because it is either expensive or you are breaking plates.

Clean the toilet before you start, and let it dry on end overnight. Trust me.

Phil
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Any high fire clay that is being disposed of will work. Toilet is prime due to the quantity from one go, but you have to smash it down quite far, below 1/4 inch screen for good results, sand-like is better. In truth old china is somewhat easier, but hard to get stuff you feel comfortable destroying because it is either expensive or you are breaking plates.

Clean the toilet before you start, and let it dry on end overnight. Trust me.

Phil

Thanks Phil; I can imagine the pitfalls of not cleaning the victim... :wacko:
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Trying the lively adobe mix, with using a higher clay/ash slip as a surface coat... though now im kicking round the idea of busting up a couple old toilet tanks and letting the pieces tumble around in my cement mixer for awhile and adding that to the slip.

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Trying the lively adobe mix, with using a higher clay/ash slip as a surface coat... though now im kicking round the idea of busting up a couple old toilet tanks and letting the pieces tumble around in my cement mixer for awhile and adding that to the slip.


Ulric; would you explain this lively adobe mix and clay/ash slip in more detail please ?
(my skull can be thick sometimes)............... B)
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Ulric; would you explain this lively adobe mix and clay/ash slip in more detail please ?
(my skull can be thick sometimes)............... B)



These are the only two links I have, found/stumbled on other sites and Tim's video provides some info in regards to it to.
http://www.knifenetwork.com/workshop/tut_large_adobe_lively.shtml

Now, gather a few gallons of fine sand and a couple gallons of wood ashes along with an arm load of dead grass, dried moss or straw. Take one one of the buckets of cactus tea and add in one gallon of clay slurry, one gallon of sand and one gallon of wood ash. Mix thoroughly with a stick or something. Don't use your bare hands. The ashes in the mix along with the abrasive action of the sand will literally eat the skin off your fingertips. Use gloves when needed. Don't add any dead grass yet.


in trying this, after the mass adobe has been placed and dried that idea is try a ..thinner application of clay/ash/sand ratio mix over that.


None of these are in short supply around here much just needing a shovel and bucket to collect.
Trying to get the 'rocks' or, what I was raised to identify as 'iron ore' out of the clay
can be a bit annoying, but I've got plenty of time on my hands. :-)

Im using clay dug from a retention pond in the 'pasture', fine sand left from some concrete
projects, ash from a recent pile of logs/brush we burnt off and dried/shredded bamboo leaves
for the insulation layer.
slip/slurry coat clay a clay/ash...

If/when I get my cement mixer back, I want to bust up a toilet tank toss it with some large pipe fittings and spin it for awhile and see porcelain fines I can get out of it. If I can get a decent amount I may through that into the slip/slurry mix for a surface coat.
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Thanks Ulric this looks interesting and I have most of the elements at hand for this
B)


If i can find it again, there was a site (or 3) that told you how to check the soil/clay content for suitability.


Testing Soil
If you are not sure about the soil you want to use, there is a way to test it out. Fill a glass jar about 2/3 full of soil. Add water until the jar is full, and shake it for about 2 minutes. Set the jar down and let it sit overnight.

When you check the jar, the soil should be broken up into two distinct bands of dirt. The sand should be settled on the bottom with the clay on the top. There should be more sand than clay. A ratio of about 70 percent sand to 30 percent clay is ideal for making adobe brick.


I didn't like the...idea of waiting 3-5+ days for it to dry out on it's own, so... I set
the thing over a fire to dry it out. There are some nice cracks to fill in, and some of the thin spots
flaked (1/16-1/8 thick areas) but the rest is HARD/Solid. Once it's cooled down enough to handle, I'll make a thicker batch (first was a tad, wet) finish the fill in... dry it then try the slurry coat.
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gympsum (ie sheet rock) is somewhat fire resistant, but breaks down at high temps. there's a reason that you don't see sheetrock left after a home fire.


http://www.usg.com/sheetrock-gypsum-panels.html#tab-faqs


Q: What is the maximum temperature that SHEETROCK® Brand Gypsum Panels can withstand?

A: SHEETROCK® Brand Gypsum Panels can withstand temperatures up to 125°.
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  • 5 years later...
On 7/28/2010 at 4:46 PM, welder19 said:

Definately leave out the portland.
Use a high temp clay, I prefer Kaolin, which runs $10-$15 for 50lb, use silica sand or grog, approx 20lbs grog/sand to 50lb of clay, to reduce shrinkage and add strength and if you want it to be insilated add in some foam beads, bean bag chair filling works good, add as much foam as your mix will allow and still hold together, add water very little at a time and mix well. Then do 1/4"-1/2" hot face, [clay mix with no foam in it].
Let it dry slow and then fire it slowly, if you fire it too fast it will crumble.
It will handle 3000F with no problem.
I use this mix for my forges and casting furnaces.

welder19

sorry about the message in an old thread.But this is exactly what I think I need. <<<:wacko:>>> Has anyone made this formula in the 5yrs, and how did it work. Where else can I get bead foam? For the hot face do you let the first part dry then press on the half inch hot face and let it air dry? How thick should the first wall be? After it is cured and sure it is, can a person paint the inner face with itc-100.

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