Material To Make Ceramic Or Porcelain Components

[kubeek]

Hi, I need to create a mechanical part that will withstand high temperatures and be non-toxic, so I think that porcelain or some other kind of ceramic will be good for this. Basically what I need is something with the hardness of standard electronics ceramics - see this for example http://media2.rsdelivers.cataloguesolutions.com/LargeProductImages/R421845-01.jpg

 

One shop advised me to use some plastic porcelain clay that they already have, but I also have access to different base materials, so the question is, what mixture of materials would you suggest to achive a quite hard and tough outcome?

[Marcia Selsor]

If you are talking spark plug porcelain , that is fired industrially at a very hot temperature of Cone 30.I don't even know how hot that is.

[kubeek]

I don´t think I need that much strength, just something that isn´t brittle.

[Biglou13]

Epk and some other stuff.

[Mart]

What is it you need to build? What temperatures are we talking about?

Will porcelain with grog to the trick? You can not bang on it with hammer but it's still strong and can withstand heat and stress.

[kubeek]

Temperatures will be around 300°C. I really have no idea what I need, but from what you say it seems it should suffice. The only thing is that the air heated by this will be breathed, so I don´t want any nasty chemicals to leak out of the material. Could you give me some percentages of what the mix should contain?

[Marcia Selsor]

300 C isn't very hot..are you talking firing temperatures or the functioning temperatures?

 

Marcia

[Wyndham]

Is there going to be an abrasive,part against part or only in the air flow? moisture, or other factors like rapid change of temp ?

All of this and more can go into deciding if one clay or glaze might be better than another, it's in the details

Wyndham

[kubeek]

300°c as in operating temperature, the idea for firing is a tiny kiln just big enough to fit the thing, so maybe 6x6x6" internal volume heated by a propane torch. Do I have to keep some heat profile, or do I just need to achieve the proper firing temperature and thats it?

 

Temperature will not change extremely fast, but lets say I´d like to ramp it up between 25°C and 300°C in about a minute using heating wire wound around the thing, so there may be some hotspots. I might embed the wire into the thing so there would be better thermal contact.

Also no abrasive parts just air, and there should not be any moisture in normal oparation, apart from the moisture contained in normal air.

[GEP]

These sound like questions that really should be asked of a Ceramic Engineer, rather than potters and sculptors. In the US I believe all (or most) of the Ceramic Engineers studied at Alfred University in New York (someone correct me if I got that wrong), which would be the next place that I think you should inquire. 

 

The best answer that we potters usually have when someone wants to try something new is "try it and see" and "keep testing until you get it right."

 

I would say to try the porcelain you already have, and also the porcelain+grog suggestion that Mart provided. Fire it all the way to maturity, whatever is the highest temp your porcelain is rated for. And then see if it works!

[kubeek]

I know this isn´t  the best suited forum for such questions, but I couldn´t find any public forum that is better suited (you can imagine how many people in the world start out of sudden making technical ceramics ).

Anyway, thanks for the info, but could someone please post some recipe for the porcelain and porcelain+grog mixtures? Im having hard time finding some working numbers.

[GEP]

oops I misread your first post. I thought you already had some porcelain, but now I see the shop was trying to sell you their porcelain. In that case, go buy their porcelain, no need to make your own. If you need to buy grog too, buy the finest grog they have. As for how much grog to mix in, there must be a standard range that clay manufacturers use, hopefully someone else here knows that?

[Wyndham]

Get a bag of cone 6 porcelain and some grog, wedge some grog into the clay, make the part, allow for 12% shrinkage and give it a go. Remember solid bodies take forever to dry and slow fire to maturity.

 

That's about all I can come up with. You may need to make many before getting it right or not, Wyndham

[Biglou13]

I just wedge a few handfuls in. (Ok I've wedged in up to 10% grog to finished clay weight. It could have taken more)

 

Check out post on custom stamps. Some have digital cad cut ceramic that may serve your purpose. Send the design /specs pay and wait for it in the mail. It's not that expensive. Save your time and brain cells and let the pros handle it.

 

Unless you tell us more details. Your not going to get much intelligent or more help. (Hence my first cryptic answer)

 

Do you need hardness or do you need the piece not to flex under load?

 

If you make some invention and make a ton of money what's in it for us? Do I come to your shop and ask for you to make a whirlygig for free?

 

There is fine white grog available, most other grogs will off color your piece. Are you sure you need porcelain,and why?

 

Who are you and what are you building? What do you have to contribute? Wanna make me some custom ribs?

[kubeek]

First of all, it is no invention and I don´t plan to make any money with it. If it were, I would hire professionals to do it for me instead of playing with it.

Color doesn´t matter, porcelain was recommended to me because a) its what they call all the technical ceramics in here, and b ) it is supposed to be harder then other pottery.

Basically what I am building is my approach to design a vaporizer. Here is a crude model of what I plan to make, dimensions 40x40mm

komora1.PDF

komora1.PDF

[Wyndham]

A small piece like that should be rather easy. I don't think grog would even be needed, but either way.

Get some cone 6 porcelain, roll out a small slab about 2 in on a side and about 1/2 in thick Let this dry then bisk fire to 06= about 1832 deg f measure the size and thickness, record this for later use. Get a drill press and the bits you want to use and in a shallow dish of water , drill your outside diameter disk then the interior holes. Fire this unglazed. Measure the results and recalc for the shrinkage. Make prototype 2 and see if it comes out to the size.

Using this information plan for either stacking several pieces together or getting a small Harbor Freight Arbor press an make a mold for pressing the clay into a cylinder with holes or drilling them.

It will depend on how many you need and when.

I'm guessing the rings around the outside are for "O" rings

Wyndham

[kubeek]

The outside is a spiral groove to fit the heating wire, but that is just a "nice to have" feature, not a must. I am not yet sure on how I will make the shape out of clay, but I guess I will have to improvise something.

The dimensions of the thing are not critical at all, so just accounting for *some* shrinkage will probably do.

The idea of stacking pieces together seems nice, would it be possible to stack the plates of clay in such way that they would become one big piece after firing, without destroying them by force? I imagine something like a more pasty clay between the layers that would sort of glue the plates togeter.

[kubeek]

Also, how fast should the temperature ramp up? And am I right that the clay needs to be left to dry before I put it in the kiln?

[Wyndham]

It needs to be bone dry then use the slow bisk firing schedule on the kiln controller. You might try a hight temp kiln cement to cement the layers together.

You would need to play around with different layer thicknesses for drilling. The outside could be cookie cutter cut by making a cutter from banding strap steel soldered  together to make a circle of correct diameter.

Wyndham

[kubeek]

Propane-butane torch means I don´t have no controller except for myself along with a temperature gauge which I will put >somewhere< inside the kiln. Is it a big problem if the temperature ramp is too fast, or if I overshoot the desired firing temperature? I dont mean overshoot by many hundreds of degrees C, but how critical is the final temperature?

[Biglou13]

420 project????

 

Isint 365 degrees or close to it the magic number.

 

Secondly due to the nature of the ceramics we are talking about a heating wire just around the outside of form will not be efficient. The ceramic will not conduct heat . Most of the formulas of clay mentioned are not very good conductors of heat. And more than likely have a more insulation effect. Like porcelain in spark plugs.

 

You prolly can get away without glazing item. You don't really need porcelain, most any clean clay fired to maturity will work. I'd definitely stay away from clay bodies with carcinogens, and or other toxic stuff.

 

The only way this item will work for,what I think you're going to use is to heat entire ceramic piece to slightly above target temp. The ceramic piece will become source to vaporize "the volatiles"

 

I can appreciate your,thinking outside of the box, but there are easier solutions.

 

Using pre existing "devices". Be it ceramic glass, or other....use a heat gun with dimmer switch, use a digital infra red thermometer and dimmer to calibrate heat gun to target temperature. With this you can use pre existing "device" to vaporize your "volatiles" and possibly use the ceramic part as a "grate"

 

Maybe put down the bag of Doritos, step,back and re asses project.

 

Ok,back to ceramics, If you look at fire bricks some retain heat, some will insulate. See hard brick vs I.F.B. . Knowledge here will help decide what material/clay to choose if you stick with original concept.

[kubeek]

I already have one device I made, but it didn´t work very well. So now, a few years later, I thought I would try another approach.

Anyway, the main point of this exercise is not really the finished product, but rather wanting to try something new, something not entierly easy. My dayjob is designing electronics, but often I just want to play with some new stuff, and this guy http://www.youtube.com/channel/UCivA7_KLKWo43tFcCkFvydw has been a great inspiration in trying weird and complex projects.

[kubeek]

I was doing some more research, and I found out that if I want to have better thermal conductivity I should use alumina cramic. Does any one have any working recipe? I found out that I should have something around 95% Al2O3 and then some SiO2 and MgO, but I am not too sure about what amounts or if I will need anything else to make the clay.

[Wyndham]

There is no plasticity in the things you mentioned. They would have to be pressed into a form and the bonding temp will likely be very high. 

just guessing though

Wyndham

[Bob Coyle]

For what it is worth, I made a set of ceramic terminal blocks from cone 6 50/50 mix ( its what I had available)  from Laguna clay. They were for the 50 amp circuits coming from my electrical box to my kiln. The work fine and would have no problem with any reasonable heat you would expose wiring to.