Mellin

Home made refractory

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And people say blacksmithing is just heating stuff and hitting it :)

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Anyone looking into cerium oxide further should look at lapidary suppliers I have found 13 dollar pound prices to 10 in bulk 25-44 pounds. I am dissatisfied with having only 8 oz to work with so I will be ordering more.

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Made a 100g zircopax tile and a 100g cerium oxide tile today. I kind of botched the  cerium tile as I think I added too much water,  only drying will tell. With the extra mixtures I had leftover from making the bricks i coated parts of a foamy fire brick and fired the forge up.

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Kinda cool watching the patterns move on the cerium oxide patches. The cerium oxide turns yellow after it has been fired but reverts back to its Orange color after a couple of minutes.

The black flecks I can either assume is contamination from fire clay or the actual brick melting.

Mellin

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So my test tiles shriveled and cracked badly I used way too much water.

Can someone go into their process for mixing Veegum. Do you make an excess solution of water veegum that would say be 6% by weight them mix with the zirconium silicate. I tried doing this with 15 ml of water and it was a terrible failure.

However out of this failure I decided to fire the bits that I had left over in my forge.

The zircopax tile blew up but the fragments fired very very hard.

The cerium oxide again reached a yellow color outside the furnace for a short time but reverted back to Orange. the consistency chanced to A hard chalk compared to the fully glass zircopax. A note that the cerium tile started with almost triple the water but did not explode when heated. Areas around the cerium oxide stayed visibly red hot many minutes past shutting off the burner and removing from the forge.

Monkeyforge or Mike of either of you have advice on mixing this stuff I would greatly appreciate it.

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I presume you already know about placing the wet tile on paper towels to help leach water from them while they are becoming greenware.

You may not have heard about using vibration to liquify refractories with a lot less water...:)

 

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I had them setting on plastic last night with a fan nearby tonight my tile is setting on cardboard. I have not looked into vibration for liquification. I will look but it sounds likely out off my league. Plus I still need to get the Veegum into the water fully, I'm sure I didn't get anywhere near full particle mixing.

Just the process on how to mix the Veegum into water and get the right amount of Veegum and water into the zirconium silicate basically.

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Am I just complicating things by trying to dissolve the Veegum into water first ? from what I am picking up from other posts people are just mixing everything at once. Veegum manufacturer says to mix into water then mix water into clay. Also if you have a technique for vibration mixing I would love to hear it.

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36 minutes ago, Mellin said:

I have not looked into vibration for liquification. I will look but it sounds likely out off my league.

 

The guy who came up with this trick (so far as I know) uses a rod connected to a reciprocating power hand tool. Lots of guys have built their own vibration pad by adding an off-center wieght onto a motor shaft, which is screwed onto a steel pan; low-tech is my favorite magic :)

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I've used a palm sander with no sandpaper on it  on concrete countertops to get air out. Would that work good for this also?

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I mixed everything dry, put all the powders in a jar with a lid an rolled an tumbeled that. The mixing instruction for bentone are different from the one for veegum. I remember reading on digital fire they recommend " a powerful. Mixer". If your mix is very Mike's paper towel suggestion may work, drywal or a plaster bat will too. Beware of of drying to fast though. 

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I actually have a trove of old sanders i don't plan on ever using again for their intended purpose. I will consider making something of the sort as I build filter boxes for my shop this weekend. Also I did not bag the mixtures and let them set so next time I will treat it like a normal clay body.

It's colloidal so it will never settle out? Why don't I just mix all my Veegum into the least amount of water noting the original weight of the Veegum before the water. Then I'll have a solution containing excess. So when I need to use it i can take enough to get the Veegum weight I desire and use that. It seems the most simple now that I think about it.

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I don't know what literature you're reading about using Veegum but everything I read says it's used as a "fluidizer" to make pottery clays more plastic with a higher thin wall strength. The strengthening is attributed to it's extremely adhesive nature. Fluidizing allows the particles to slip past each other more easily so the vessel walls don't tear when being thrown thin it also makes wet clay more slippery to improve thin wall tear resistance. 

However, the HIGHEST concentrations I saw listed were in the 0.3% - 0.4% and reports of attempts to use greater than 0.5% yielded pottery clays that were so plastic it was difficult to get them to hold their shape.

Veegum and Bentonite are two different if similar clays. It's easy to be fooled though, there are companies offering both types with one or the other in their name. For example (I just made up) The Veegum Clay company which offers 40 types of Bentonite clays. Or the Bentonite Clay company which offers several grades of Veegum.

The fora and blogs written by mud slingers are better sources for objective opinion and working techniques about various clays than the manufacturer's marketing department. Oh and the addition of less than 0.3% Veegum to Kaolin (porcelain) clay increases the drying time many times. 

This forum is NOT the place to be reading about: ratios, mixing, using and characteristics of Veegum as a clay additive.

Frosty The Lucky.

 

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 I read on Veegum in the clay forums however most act like it is already common knowledge and unfortunately I missed my colloidal suspensions of smectite clay class in school.

However the most basic rule for getting clay like Veegum into water is to add energy, the more the better.

Shear force brought up in forges 101 is great for this so a shear vane mixer described by frosty is awesome unless you don't want to spend an hour plus mixing.

Another way to add energy is heat so heating the water prior to mixing should help as well.

Lastly time will help, an estimated six months of soaking the clay to get 100 percent hydration.

What i am trying to achieve is good hydration of my Veegum T, (I have the brand name as to not get confused), so when I mix it with my Zircopax Plus  (again brand name as to not get confused) I can get a homogenous mixture with my Veegum particles being as small as far apart as possible.

I have already decided I am going to mix all of my Veegum into the least amount of water i can noting the weight of the Veegum and water separately so I can have a suspension with a known ratio. Then when the time comes that I need 3 grams of Veegum I can take x amount of the solution and be reasonably sure that there is a correct amount of properly hydrated Veegum suspended within that sample.

I have been in the process of moving so I haven't been able to draw up any plans for my forge but assume it's going to be a 2 burner side draft oval forge. I am also going to see if any of my local colleges could mix and pug my "clay" for me. That seems to go along the idea of work smarter not harder.

Also for the long forgotten third rule of blacksmithing I think it would have to be "always assume everything is hot in a blacksmiths shop until proven otherwise"

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 I should also add that you are correct I want my zircopax and my cerium oxide to be able to be worked without tearing so that's why I am adding veegum. Zirconium silicate and cerium oxide are almost entirely non-plastic or in  ceramics terms the opposite of plastic is "short". I did not explicitly state that as My intention for using Veegum T in this circumstance, that is my fault for assuming since I was asking about the moldable high temp refractory. I know Veegum in the end will be detrimental to the high end temperature rating of this refractory but I plan on using this as a learning experience to base future experiments off of.

Mellin

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So I fired a tile with a composition of 48.5% zircopax 48.5% cerium oxide 3% veegum t. It fired well however I dropped it and it broke into 4 pieces. The hardness is not quite that of pure zircopax however it still exhibited good thermal shock resistance I poured water on a chunk while still hot. If I could reach a higher temperature in my forge I may be able to get the full sintering hardness from the cerium oxide but the temperature is just out of reach currently.

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On 3/31/2018 at 11:00 PM, Mellin said:

I know Veegum in the end will be detrimental to the high end temperature rating of this refractory but

Not very detrimental in such small percentages, and the zirconium silicate has such a high-temperature rating that Veegum's lowering to temperature use ratings are more than compensated by its likely being the only plasticizer and binder that will do the job?

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18 hours ago, Mikey98118 said:

Not very detrimental in such small percentages, and the zirconium silicate has such a high-temperature rating that Veegum's lowering to temperature use ratings are more than compensated by its likely being the only plasticizer and binder that will do the job?

Indeed. A necessary trade.

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1 hour ago, Mellin said:

Indeed. A necessary trade.

It's not actually a trade, it's a common method of sintering zirconium and other extremely high melt temp materials like tungsten, molybdenum, etc. The addition of various lower melting elements and compounds to the material being sintered can make all the difference unless you REALLY want a multi axis press capable of a couple thousand bars of pressure that is.

One of the guys in our club sent me a couple links about sintering zirconium which made me do some more reading because what they were talking about didn't match my grossly oversimplified and in most cases wrong idea of what sintering is. I won't link you to the dental zirconium sintering sites, the WIKI article is a better place to get started. Parts read like HooDoo magic to me. It's a good place for a learning curve junky to get lost. :)

 https://en.wikipedia.org/wiki/Sintering

Frosty The Lucky.

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Good article, Frosty.

This statement was what jumped out at me:

"... which is one of the main reasons why much ceramic technology is based on the use of fine-particle materials."

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Digital fire beats Wiki re. ceramics for sure. Now we're back up to 3.5% VegumT. but that's for sintered zircopax kiln shelving rather than conditioning throwing clays. My mind's cross referencing things it shouldn't. . . .AGAIN!

Fine particle size increases the sintered density for less heat and time sintering. While it didn't jump out at me the statement did catch my notice, I learned a different classification and particle classification in the materials lab. I don't think ASTM classifications missed so now I"m wondering about how they tie in. 

You know Mike, I'm wondering if we're going to have to put up our burners and go play in the mud for a while?

Frosty The Lucky.

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Mud's good, I like playing in mud. ESPECIALLY when I get to fire it scary bright yellow with a home made burner. :)

Life is sooooooo good!

Frosty The Lucky.

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4 hours ago, Frosty said:

Mud's good, I like playing in mud. ESPECIALLY when I get to fire it scary bright yellow with a home made burner. :)

Life is sooooooo good!

Frosty The Lucky.

I'll second that Frosty you're spot on.

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As an update when I crushed two of the tiles they broke into splinters which would lead me to believe I have sintered them at least partially.

The back wall was coated in the 48.5/48.5/3 mix and makes a considerable show.

I also found an old muffler but i don't see it being a forge any time in future.

Mellin

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