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PeterH

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  2. Deep Black Glaze

    in Clay and Glaze Chemistry

    Posted · Edited by PeterH
    Added Hasselle Copper Matte reference

    8 hours ago, Bill Kielb said:

    Good choice on mixing, just to be aware with glazes you are not likely to achieve the surface characteristic of the black 4.0. It is still a glass, matte glazes are a bit rougher on the surface and definitely refractive, so the surface will likely never be near the super dry matte of the 4.0. You actually may get a desired effect of extreme black underneath a very clear glaze.

    Firstly, I don't doubt Bill's advice that a clear glaze over a black glaze may make it appear blacker.

    However IMHO it emphasizes the real differences in the physics of Black 4.0 and glazes (pedantically the surface of the Black 4.0 pigment and the surface of glasses/glazes). Because covering Black 4.0 with a varnish seems to loose the magic †.

    Black 4.0 claims to reflect about 0.05% of the incident light (this varies with the incidence angle of the light ‡). For window glass (and presumably glazes, which are glasses) the figure is a lot bigger (even with an anti-reactant coating).
    How-does-anti-reflective-glass-work.png
     

    † https://help.culturehustle.com/en-US/articles/black-40-faqs-121873
    No, sadly this paint is not waterproof and may get damaged outdoors. There is no clear varnish as matte as this paint to protect it and attempting to use any top coat over BLACK 4.0 will likely ruin the finish.

    ‡ https://www.dpreview.com/forums/thread/4739693
    Black 4.0 - deeper into the Dark Side?

    PS If pressed I'd be inclined to try these options.

    1) A clear base glaze containing lots of black stain. Maybe looking at the difference in appearance a matte base-glaze gives.

    2) A deeply matte copper oxide surface (based on a copper matte raku but without the color-forming reduction). Wildly non-functional, but the optics might be interesting. I haven't tried it but Hasselle Copper Matte is  a frit/glass less copper matte recipe in
    https://ceramicartsnetwork.org/docs/default-source/uploadedfiles/wp-content/uploads/2015/08/15rakuglazes.pdf

  4. RedArt Terra Sig Question re. Ball Milling and use on Stoneware

    in Clay and Glaze Chemistry

    Posted

    On 7/18/2024 at 1:00 PM, TonyC said:

    Lastly, can I use these red terra sig recipes on stoneware or are they exclusive to earthenware?  Sorry of this is a dumb question, but I've searched resources and it is not clear to me.

    https://digitalfire.com/article/super-refined terra sigillata
    Firing Ranges and Natural Clay Colors Achieved with Terra Sig
    A true burnished surface cannot be fired above cone 012. Beyond that, as described earlier, the compressed surface crinkles on a microscopic level, and you loose your shine. On the other hand, highly polished (not burnished) terra sig surfaces can be fired as high as cone 02 with the polish intact. At higher temperatures, terra sigs will give an appealing satin finish, but the high shine will disappear.

    I have applied very thin coats of terra sig to bisqueware with adequate results, but it never produces the level of shine or durability of surface achieved with a sig applied to bone dry clay. Terra sig applied too thickly on bisqueware will almost always crack and peel.

    At cone 012, Redart sig gives a bright brick-red-orange color. At cone 08 it gives a classic brick red, and cone 02 it gives a red brown. At midrange and highfire temperatures, a Redart (or other earthenware clay) terra sig will fuse and become a glaze.

  6. help finding kiln manual

    in Equipment Use and Repair

    Posted

    7 hours ago, Babs said:

    @PeterH is a great researcher   hopefully he can find it.

    To emphasis the point: I have zero expertise or experience in this area, unlike the experts in this group. So all I'm doing is trying to find items on the net that might be useful. Buyer beware!

    Remembering Niel's comment:
    The elements cannot touch like that. You'll need to separate them and pin the upper one into place so that it can't sag. The element is probably pretty brittle, so you'll want to heat it with a torch and use pliers to manipulate it. At some point you'll want to replace that brick, because pins can only do so much. 

    An initial YouTube search finds quite a lot of plausible-looking videos when searching for
    How to Repair a Bulging Element: The Paragon Kiln.

    Some apparently relevant items (ignoring element resistance checks and element replacement for now) ...

     

    PS

    7 hours ago, Babs said:

    Pin that element before turning on again. There was a demo maybe by @Min on just how to do this.

    Min, any memories? Was it a video or text? Do you use other names posting on other sites (e.g. YouTube)?

     

     

  7. help finding kiln manual

    in Equipment Use and Repair

    Posted

    Getting to be a question for the experts. However two points.

    1) Don't try to power-up the kiln again until you have removed the apparent short-circuit where the element crosses itself. It could damage something. (How to bend aged elements is outside my experience, they may be brittle.)

    2) Can you:

    -- Confirm that you still have power to the socket (i.e. your test didn't trip the breaker).

    -- That you started the test by activating the kiln sitter (with a cone in place), otherwise power wouldn't get to the kiln proper. (If you don't have any cones the experts probably know how to improvise without a cone for the test.)

    -- Say if the pilot light came on during your test.

    3) For now only look at the wiring when the kiln is unplugged.

    Do you have a meter that measures AC volts & ohms, and what is the lowest scale you can measure ohms on?

    Possible circuit diagram
    https://corp.paragonweb.com/wp-content/uploads/WS1193.pdf
    ... note that one element is shown running off a relay.
    - It would be nice to confirm the presence of the relay. (If it's not there it's the wrong diagram.)
    - Does the relay feed the good element or the damaged one?

  8. How to nicely lay out an evenly spaced pattern around a pot?

    in Studio Operations and Making Work

  10. help finding kiln manual

    in Equipment Use and Repair

    Posted

    18 hours ago, PeterH said:

    Found the circuit diagram for what might be your kiln at:
    https://corp.paragonweb.com/wp-content/uploads/WS1193.pdf
    ... at least the power requirement seem similar to the ones on your plate.

    If that is for your kiln it gives the model number a S1193 rather than 1193D. In which case the manual might be at
    https://corp.paragonweb.com/wp-content/uploads/IM104_S_SnF_TnF_Inst-Service-Manual.pdf
    ... although there is very little on the S models.

    This might be relevant.

    PS Test kilns, being smaller,  tend to cool faster than full-size kilns.  Which can influence the appearance of some glazes. My impression is that people with both a test and full-size kiln try to ensure that the test kiln cools at a similar rate to their full-size kiln. Which is a lot easier if the  test-kiln has a controller fitted!

  12. help finding kiln manual

    in Equipment Use and Repair

    Posted

    Hi, I cannot see from your picture what model of kiln-sitter you have fitted.
    Here is a manual for the LT-3 & LT-3K. If you have a different model can you let us know what it is.
    http://www.fireright.com/docs/kilnsitter/lt3andk.pdf

    Found the circuit diagram for what might be your kiln at:
    https://corp.paragonweb.com/wp-content/uploads/WS1193.pdf
    ... at least the power requirement seem similar to the ones on your plate.

    I've had no luck finding a manual on the five pages at
    https://corp.paragonweb.com/support/instruction-manuals/
    ... page selector buttons at the bottom of each of the five pages

     

     

  14. Issues w slip/ glaze popping off

    in Studio Operations and Making Work

    Posted

    45 minutes ago, Io Palmer said:

    the midrange clay is called Georgie’s G Mix and the slip recipe is Eva Kwong Slip Recipe.

    Is the clay
    G-Mix 6 https://www.georgies.com/gcc-clay-mid.shtml
    or
    G-Mix 10 https://www.georgies.com/gcc-clay-high.shtml

    Is this the slip?
    https://ceramicartsnetwork.org/ceramic-recipes/recipe/Kwong-Mangus-All-Purpose-Greenware-Slip-with-multiple-color-options-169109#
    ... can you confirm that you are still using the same bags you used previously

  17. Toxic mold in clay?

    in Clay and Glaze Chemistry

    Posted

    On 2/12/2022 at 4:05 PM, Hulk said:

    bein' curious, ah:

    The OxiClean™ formulation is a combination of ingredients, the key ingredient being sodium percarbonate, sodium carbonate, surfactants and polymer.

    Sodium percarbonate seems to be a form of sodium carbonate with "hydrogen-peroxide of crystallization" rather that "water of crystallization". 
    https://en.wikipedia.org/wiki/Sodium_percarbonate
    It is an adduct of sodium carbonate ("soda ash" or "washing soda") and hydrogen peroxide (that is, a perhydrate) whose formula is more properly written as 2 Na2CO3 · 3 H2O2.

     

  20. Is there an exhaustive list of all metal oxides that can be used in glazing?

    in Clay and Glaze Chemistry

  24. Mocha slip

    in Clay and Glaze Chemistry

    Posted

    Any relevance???

    Cardew's Red† aims to suspend Fe2O3 crystals in a glaze body in which Fe2O3 is insoluble.

    The recipe is:
    44% North Cape nepheline syenite
    34% Potash felspar
    20% AB clay
    2%  Kaolin

    ... which is attempting to achieve
    0.8 K2O
    0.2 Na2O
    1.17 Al2O3
    0.05 Fe2O3
    5.35 SiO2
    ... with a significant emphasis on no Ca and other alkali earths.

    The idea seems to be that the Fe2O3 crystals in the clay become suspended in the melting glaze. So it's hard to argue that the F2O3 acts as a flux in this case.

    So remove the Fe2O3 from the ingredients and the resultant glaze might not dissolve mocha patterns?

    † Pioneer Pottery, Michael Cardew p160

    PS It's a cone 8 glaze, perhaps a little boron?

  25. Kiln blowing transformer with new elements

    in Equipment Use and Repair

    Posted · Edited by PeterH

    5 hours ago, Ossoceramic said:

    I changed the elements and then on my first cone 6 glaze fire

    2 hours ago, Ossoceramic said:

    So I just need to replace my elements with 208 volt to bypass the need for the buck transformer altogether. 

    I'm having trouble scoping things.

    Without the buck transformer:
    The 208V KM-1027 kiln only fires to cone 6 (the 240V fires to cone 10).
    https://skutt.com/products-page/ceramic-kilns/km-1027/#specs
    ... if you regularly fire to cone 6 would the element life be a problem?

    With the buck transformer:
    1) The 240V KM-1027 draws 48A. If you are using a 208/240V buck transformer presumably the 208V side needed to draw 48*240/208=55.4A, does a 60A breaker meet the regs?
    2) Was the transformer rated at >11,520W?

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