# homemade crucibles



## southernau

Anyone here have experience building their own crucibles? What is the best material to use? Can refractory cement be used as a crucible?


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## dtectr

In a word, " yes". 
There is an excellent video made by one of our members on youtube. I an unsure of the title or poster but a search on the forum with those terms should be productive. 
Learn to use the "search" function - this has been discussed at some length before.


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## DONNZ

Here you go.

http://www.youtube.com/watch?v=E3my6-nxFjM


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## dtectr

S-O-C-K-S
(¡Eso si' que es!)
Sorry , a spanglish joke 
"yes, that is it!"


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## lazersteve

I loved this video when it was first posted and I still love it now. Very informative and inspiring! After viewing it some years ago I tried my hand at making some dishes and found it was not as easy as it looks.

The major problem I had was breakage of the green dish when the mold halves were separated. The next biggest problem was that the surface of the dish was too rough to use for melting.

I used premade refractory from Empire KAST-O-LITE 30 LI PLUS. I tried several others, but this one made the best quality (but still not as good as factory made) dishes. I never mixed any fireclay in the refractory so perhaps that's where I went wrong.

When it was all was said and done, I decided it was cheaper to buy the dishes and crucibles than to go through all the headache of making my own.

After seeing the video again, I may just take another shot at it this weekend for kicks.

Steve


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## Geo

from what i understand about clay (ive done some molding but not with fireclay) you can make the cast smoother by making the clay wetter. this means it has to stay in the mold longer to dry but the finish should be nice and smooth. if time is not a factor try over wetting the clay and letting it set longer before removing it from the mold.


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## kuma

Hello all , how are tricks today?
I hope all is well! :mrgreen: 
Just a thought here , but could a rub down with some fine glasspaper not smooth the surface of a homemade crucible enough to melt gold powder efficiently ?
I only ask as while watching Noxx' video yesterday ( melting gold powder on ceramic blanket http://www.goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=12937#p129599 , cheers Noxx! ) I noticed how easily the gold powder fell together and agglomerated on the blanket once molten , and I remember feeling a sense of supprise at seeing how well it did this considering the apparent rough texture of the surface of the ceramic blanket.
I've never seen or held ceramic blanket , but from what I could tell it didn't look smooth at all , what am I missing ? :roll: 
All the best everybody , and kind regards ,
Chris

(Edited for clarity)


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## DONNZ

So far I'm batting 5 for 5. None useable. To ruff. 

Next step, grind the brick into a fine power. 

I want some: ceramic blanket for my furnace. 

They also make paper and board.

http://www.ebay.com/sch/i.html?_nkw=ceramic+blanket

http://www.ebay.com/sch/i.html?_nkw=ceramic+board&_frs=1&_trksid=p3286.c0.m359

Shipping sucks.


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## qst42know

Geo said:


> from what i understand about clay (ive done some molding but not with fireclay) you can make the cast smoother by making the clay wetter. this means it has to stay in the mold longer to dry but the finish should be nice and smooth. if time is not a factor try over wetting the clay and letting it set longer before removing it from the mold.



From making my own cupels not crucibles, to much water and they are certain to crack when fired. The texture has to be just right, damp but still crumbly. There is definitely a learning curve to it.


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## DONNZ

First attempt after grinding fire brick to a fine powder. Getting that smooth look.

Only mixed 4 tsp clay to 6 tsp fire brick for my test. Walls are to thin, I will correct this on next attempt.


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## southernau

What mesh did you grind the fire brick to? Those are impressive looking crucibles you made there!


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## DONNZ

#P1000389: Taking it apart, checking my work.

#P1000390: As you can see, walls to thin.

#P1000401: Left pile: ground, sifted through old tea strainer and two layers of nylon hose.

That is what I used in my first attempt. Needs to be finer. 

Right pile: ground down to a fine powder. No need to sift.

This is what was used in the second attempt. 

Pic's of tools coming. (early iron age tools) 
Everything in the kitchen, back bed room (storage room) and the garage is fair game.

Will post pic's in steps. 

And to southernau: Thank you for the message. Don't know if you received my reply. Don't think I did that right.


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## DONNZ

How I'm getting to powder. What turned out to be the best tool for the job after I removed the rust off the bottom. Just happened to have two of these. Came complete with a handle.

A PVC scatter shield or something to keep the brick from flying across the room.

Enjoy.


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## butcher

How are you drying these, I have made some out of refractory, and I am by no means not good at making them, but I have found out the slower I let them dry the less likely to crack covering with plastic helps to slow evaporation in cool spot, do not seal the plastic as moisture need to escape (also the less moisture in the beginning the better (less that will need to be removed later).

also I have tried wash coat of fine paste refractory later after some drying, helps to give a little smoother outer surface, and dampens the outside some so it does not dry too much faster than the inner clay(not exposed to air (i cannot say this was the best way but did not seem to hurt either.

Mine seemed to be fairly thick (so they also sucked up some heat from the torch).

I did some with fiber wool insulation cut up and pulled apart to add fiber to my refractory; it did seem to help some.

Mine were ugly compared to yours.

also I used my wood stove, after they dried well, I would sit them on top of the stove to dry more internally, then would set them inside the wood stove away from the coals (on a shelf at the door, where air Enters it is cooler inside the stove there, after a day there they are moved into the hot coals and fired.

Some worked pretty good giving me a few firings, some did not hold up.

I like the information in this thread, It makes me see where my methods could use improvement and this gives me some Idea's on how I may try.

Thanks keep up the good work; I have no doubt your going to make some nice crucibles.

I like to try and make my own for melting low grade metals, but I find the store bought dishes or cupels are also very cheap and use them for anything of value.


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## DONNZ

butcher,

"Mine were ugly compared to yours"

Now that's funny.

I guarantee my first 5 were uglier than yours.

I'll try that tip and let it dry slower.

My latest attempt, firmed up and drying.


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## DONNZ

A few ideas Im' kicking around. Solving some problems. You might see something you can use or not. 

Please bear with me, I articulate better than I type. Sometimes.

A few things are showing promise, some not. And some tools I'm using.

X-acto knife or single blade razor blade. Be child friendly, put out of reach.
A fluffy brush.
A compass. Mine will hold blades but your kid might loan. One that holds a pencil will work.

Small baseball bat.
Various plastic containers. I have a box full of misc. plastic containers. 
Even the old microwaved storage containers, go in the box. I never know what I'll need. The round ones good for mixing the clay, the square ones not so good.

That one with the hot pink lid, just found at Family Dollar. 6 for a $1.00. Right size, right shape.

That ball stuck in that metal sleeve shows promise for making bowls. It has a lip, the clay will have a stop. It's open on both ends and I can put clear wrap on the ball and push into place from the bottom. I believe that sleeve came out of an air compressor.

Hang on a min. my dog wants her ball back.

That DanAtive bottle is the mold for the last crucible I made. 
The label is shrink wrap. Handy?
I wrapped paper around the bottle and taped it. Trimmed the wrap with my X-o. 
Drilled a hole in the bottom with my X-o. Great drill for plastic, use gently.
Filled the bottom with Elmer's Wood Filler, thinned with a bit of water right on top, in the container. Creamy but not runny. Shrinks a bit more doing this, use a second layer.
When it dries it can be sanded. Re-drill the hole. I rubbed a little vaseline on the wood filler, so far it's holding up to the lube job.

Adding water is my preferred method when using Wood Filler on wood. The extra water mixes with the glue and penetrated deeper into the wood adding strength. And so much easier to apply.

The shrink wrap came off with the crucible. Not going to do that again. Almost didn't make it.

Next time I'm going to cut the wrap up the side on the seam about ¼" from the bottom going towards the top. When the clay sets up a little, give it a short spin to brake it free.
Remove the shrink wrap from the crucible trying not to damage it so I can use it again.
Insert the bottle back in crucible, slowly spin it around. It gives a fairly smooth inside.

Now to that nice smooth surface on the outside. I'm burrowing a technique from glass blowers.
I'm rolling it just as a glass blower would roll hot glass on a steel plate. 

But this presents problems, one being the clay migrates up the neck but I have a solution. It involves the compass and lends itself to another (two) time saving tips. This will be my next post and one I know you can use.


I have worked with clay before but I have never mixed it. I'm learning.


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## butcher

nice that does give many clues to how your shaping and getting good looking crucibles.
I do not understand the use of the board with holes in it.


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## DONNZ

A dish: 

First try, need to practice. And I rushed it.

A baggie, zip cut off and sides split, wood strip cut 3/8" deep and something for a rolling pin.

Something to burnish the inside. I just had a light bulb moment. I'm going to try it when the clay set a bit. 

The crucible still has kinks.


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## southernau

DONNZ, your doing an excellent job of informing the forum. Ive learned alot from your posts. Please keep posting the information.


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## DONNZ

Second dish. Over the ball and pulling the ball out the back end.

This is driving my dog crazy, it squeaks. 

I need to take a brake. I'm out to fire brick powder. 

A bit better than the first one. Not spending to much time on the outside. No need.


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## butcher

What about buying a ready made dish and use the plastic sheet betweeen this dish and your fire clay, using the store bought dish for the mold, Your dish would be the next size up, but the same shape.

Darn as soon as the weather drys up I am going to have to start playing in the mud, you make it look fun. :lol:


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## DONNZ

butcher said:


> nice that does give many clues to how your shaping and getting good looking crucibles.
> I do not understand the use of the board with holes in it.



I make um. 

If you can tell me the what for. 

I'll send you one, 4 or 9 hole, your pick.


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## DONNZ

butcher said:


> What about buying a ready made dish and use the plastic sheet betweeen this dish and your fire clay, using the store bought dish for the mold, Your dish would be the next size up, but the same shape.
> 
> Darn as soon as the weather drys up I am going to have to start playing in the mud, you make it look fun. :lol:



Everything in the kitchen is fair game. What I have using the ball is a deep dish.


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## southernau

Using kitchenware has caused me much grief with the woman of the house. She is unforgiving when it comes to her cooking equipment. I have learned, the hard way, to buy my own supplies or do without. Please keep us posted on your findings DONNZ.


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## DONNZ

Working on that next post. A bit long and may brake it down, two or three parts.
Have 17 pic's so far and captions. I have more but don't think it would be good to post so many at one time.
I would like to combine captions with pic's. It needs to be free. Photobucket?
I'm not up to date with all the tool available to me and how to use them. 

And is there a ascending / descending option that I'm overlooking when I load my pic's.


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## DONNZ

Looking for clay: There's a possibility that something similar exist in your area.

CAC

http://www.creativeartscenter.org/aboutus.html

The Creative Arts Center of Dallas 

I though she was going to cry when she found out someone out there wanted the clay. Students leave it on the shelf never to return. Two weeks later it goes to the dumpster. 

I offered to buy it. She insisted that I take it. She couldn't tell me which was Low / High fire clay by looking at it. It looks like Longhorn White hand written on the bag.

Longhorn White - A smooth white talc bodied clay that fires from cone 06 to cone 1. Suitable for handbuilding and wheel throwing.

http://trinityceramic.com/moist%20clay%20page.htm

cone bending temperature:

http://trinityceramic.com/template%201%20Cones.htm

Never used, clean, and apparently unwanted.


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## DONNZ

"butcher wrote: nice that does give many clues to how your shaping and getting good looking crucibles.
I do not understand the use of the board with holes in it."

I may have stumbled upon a better way of shaping. Rolling not good after closing the gap. Still working on pic's.

And on that wooded thing. I've made these for years and can remember only one person that knew what it was.


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## NoIdea

Egg shapped crucibles, wicked. :mrgreen:


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## DONNZ

A calcium lined crucible, a novel idea NoIdea. 

To boil or not to boil, that is the question.

I will ponder.


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## butcher

DONNZ
Darn it was not a six-coffee-cup holder for the pickup truck; I like coffee going to work, Shucks if I would have guessed (egg holder), I would not be spilling my coffee on the floor-board going down the hill in the curves.

Eggs, I should have noticed the egg in one of your pictures, along with the other crucible molds, was wondering how well the egg would work to mold clay.

Nice work on the crucibles very impressive, thank you for sharing.


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## DONNZ

Thanks, butcher

Just a basic guide. Photo's got out of control. If I ever do something like that again I will do a story board in my TextEdit. Pic. number and caption as I go. 
Couldn't function without it. Keep it in my Dock. 
Don't know what they call that using Windows but I know they have one.

Looked that up, it's called TextPad in Windows.


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## NobleMetalWorks

I was thinking about using some of the finely crushed up (ball milled) ceramic from CPU's as part of the composition of the grog in a clay crucible, I was curious if anyone has tried this? I currently use ceramic CPU's as a heat shield, it seems to work extremely well. I am not sure what the ceramic composition of the tiles that cover the outside of the space shuttle are, but I got the idea of using it in the grog from that, and watching how the ceramic seems to be able to absorb, and deal with heat when you torch CPU's to knock caps off. I can hear it crack when I do so, and I am assuming that is whatever glass or other material separating from the ceramic when heated, but I thought that if it was mixed with crushed up fire brick and made up 40% of the material mixed with 60% of the refractory material, it might work very well.

Anyone have any advice, pointers, criticism or knowledge that might help?


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