If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
watering dry clay
Marianne PS - mentioned the cone discussion to my teacher, and used the words "you must do such-and-such" (translating to German is not my forte), and she just looked at me and said "anyone who uses the word _must_ in connection with pottery....." and the look said the rest! LOL! Think she has a point? Yes she does. Nice to be reminded of it. As I said, I used to fire gas by color alone. However the point that most of us were trying to make is that if you are having problems with your firing, having cones to check your heat work, certainly makes the problem solving much easier especially when the conversation is started out with - "I do think my oven's thermometer might show a bit higher than it actually is, so maybe just increasing to 1060 or 1070 would help." Cones are only a tool. They do not make the pudding - they make replication and problem solving easier (not to mention safety). While I agree with Bob that with a good controller you don't need cones, I still say that they make problem solving much easier and that was what this whole thread started out as. Donna I love the German look by the by. I don't know why my grandmother didn't have it. Donna |
Ads |
#22
|
|||
|
|||
watering dry clay
On Fri, 19 Oct 2007 11:49:21 -0700, "Andrew Werby"
wrote: "Wes" wrote in message ... Pardon my ignorance but I bought some fire clay and it is in dry powdered form. Do I just add water and start stirring? Any idea of weight of water to weight of clay? My application is to seal a metal box that will be used for case hardening in order to keep air out. Thanks in advance, Wes [Ir doesn't sound like this will work too well, Wes. Clay shrinks considerably as it dries, while the metal will expand as it gets hot. The clay won't adhere, and will break up and flake off, making a mess. Can't you make your metal box seal itself, with bolts? A refractory gasket of some sort would help; look for ceramic fiber in rope form, or a piece of refractory sheet material. Here's a link to some of that: http://www.armilcfs.com/pages/products.htm .] Andrew Werby www.unitedartworks.com Good points! But how about if he used a *clay* box? To the OP: In the pottery world a "saggar" is a box made of clay slabs to hold pieces that you don't want to be exposed directly to kiln flames, or to contain a special environment around the pieces, They are typically sealed with some sort of soft clay for the firing, just as you wish to do. You can make your own clay slabs by rolling them out with a rolling pin on a canvas-covered board. Lay down two strips of wood on ether side to hold the rolling pin up by the desired thickness of the clay. Probably 1/2 inch slabs would be good, depending on the size of the box. The slickest way to do this is to make a template out of tarpaper (roofing felt). Moisten the back of each template piece and roll it onto the surface of the slab... it will stick. Now cut out the clay by running a tool around the template edges... a "pin" tool (like a smooth-tipped needle on a handle) is ideal for this, but even an old smooth-edged dinner knife will work, To assemble the slabs, use an old toothbrush dipped in water to scuff up the joining faces so they are rough and sticky, then press the pieces together. Leave the tarpaper on to give stiffness during this assembly. (Which means you want to design your template so the tarpaper ends up on the outside.) The scrubbed clay slurry should ooze from the seams a little. Smooth it out, and maybe smear a nice fillet on the inside using additional soft clay. Let this set up a bit, then carefully peel off the tarpaper. Drape plastic loosely over it to prevent it drying too fast, and rearrange the plastic every day or so. When it seems to be pretty hard all over, remove the plastic and let it get absolutely bone dry. You will should fire this saggar once before you actually use it for case hardening. Set the lid in place when you do this, to help keep it from warping differently than the rest of the box. Fire to at least cone 04 (roughly 1050C), though cone 6 (1200C) might be better. While I've made plenty of clay boxes, I've never actually used one as a saggar (not much need for most electric potters). So one thing I'm not sure of is what sort of clay mix to seal them with. I *suspect* that if the box has already been fired, you can use the same clay to seal it with. I don't think you should let this dry first, just smear it on and start the firing. However, someone with saggar experience may have better advice... you might want to mix in some sand or some other refractory filler with the clay, for example. Best regards, Bob Masta DAQARTA v3.50 Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Signal Generator Science with your sound card! |
#23
|
|||
|
|||
watering dry clay
|
#24
|
|||
|
|||
watering dry clay
On Sat, 20 Oct 2007 13:22:04 +0100, Rob Morley
wrote: In article , Bob Masta says... Good points! But how about if he used a *clay* box? Would that be sufficiently impermeable to oxygen? I *think* so, as long as the box was adequately vitrified beforehand. But as I have no metallurgical experience since college (back when dinosaurs ruled the Earth), I can't say for sure. However, I have heard of this basic technique being used to maintain a reducing atmosphere around pottery in an electric kiln (by including combustibles in the saggar), so it seems at least feasible. Best regards, Bob Masta DAQARTA v3.50 Data AcQuisition And Real-Time Analysis www.daqarta.com Scope, Spectrum, Spectrogram, Signal Generator Science with your sound card! |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Show & Tell: clay and beads...and more clay | Barbara Forbes-Lyons | Polymer Clay | 19 | July 12th 07 03:56 PM |
Show & Tell: clay and beads...and more clay | Barbara Forbes-Lyons | Beads | 16 | July 7th 07 04:39 AM |
self watering plants | steve [email protected] | Pottery | 3 | January 9th 06 03:45 PM |
AD: Ivory Polymer Clay Heart Pendant - Polymer Clay workshop kit featuring | MARY / STUDIO ARTIFACTS | Polymer Clay | 0 | November 17th 03 08:56 PM |
Modeling clay as a substitute for "clay bars" for auto detailing? | Jon Noring | Polymer Clay | 4 | September 23rd 03 12:36 AM |