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PeterH

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Posts posted by PeterH

  1. @Jmvelezz Finally ...

    Transformation of Six Leaves Glaze to Contemporary Ceramic Bases on the Taoism Characteristics
    http://ithesis-ir.su.ac.th/dspace/handle/123456789/2977
    ... click on  60155902.pdf near the bottom of the page.

    ... which seems to be link to  http://ithesis-ir.su.ac.th/dspace/bitstream/123456789/2977/1/60155902.pdf
    ... which looks like the same link that doesn't work when you use it directly!

    I've not found any English-language page at the university that would let me report the problems to the universities IT department. I suspect that they have got their permissions in a twist.

    PS You may want to remove the watermark before printing. How to do it depends on your system. Start with a google for something like print pdf without watermark. Don't have the file any more, but think I uncompressed the pdf file then edited it directly (on Linux possibly using pdftk & vi).

  2. A little googling if it's of any help.

    This seems to be the video, and readers comments about the email address being non-functional.
    https://www.youtube.com/watch?v=VC0QXALQT_M

    A discussion
    https://cone6pots.ning.com/video/home-made-slab-roller

    Another users experiences
    http://mudismymedium.blogspot.com/2012/04/slab-roller.html
    ... which comments on the non-functioning email & web references, and gives
    https://www.biggovtsucks.com/docs/SlabRollerModified.pdf
    https://www.biggovtsucks.com/docs/SlabRollercuttingchart.pdf

    Good hunting!

    PS A thread on a different DIY roller, with some comments that seem relevant.

     

  3. On 8/12/2023 at 10:55 PM, Ben xyz said:

    Wondering now if liquid latex (or wax) could be rolled over a plastic stencil with a small disposable paint roller as a resist layer. Need to do some tests. 

    Would it be worth trying acrylic medium as the resist (sometimes used as an alternative to shellac resist in water-etching)?

  4. On 8/10/2023 at 3:49 AM, CeramicHugs said:

    They use a process called eletroplating! Another name for it is eletroforming.

    ... or perhaps not.

    Electroplating vs Electroforming: What’s The Difference?
    https://facfox.com/docs/kb/electroplating-vs-electroforming-whats-the-difference
    image.png.fadf5bab28baf1116947929dd0e9f177.png

    Electroforming
    https://en.wikipedia.org/wiki/Electroforming
    The process involves passing direct current through an electrolyte containing salts of the metal being electroformed. The anode is the solid metal being electroformed, and the cathode is the mandrel, onto which the electroform gets plated (deposited). The process continues until the required electroform thickness is achieved. The mandrel is then either separated intact, melted away, or chemically dissolved. ... my emphasis

    PS Note that when the form is to be separated from the mandrel it is advantageous if the electro-deposited layer is only weakly attached to the mandrel. For electroplating strong adhesion is desirable.

  5. 1 hour ago, Jmvelezz said:

    Can some one please send me the articule of the TRANSFORMATION OF SIX LEAVES GLAZE TO CONTEMPORARY CERAMIC BASES ON THE TAOISM_CHARACTERISTICS?

    the page send error

    jmvelezz@unal.edu.co

     

    thank you

    I would keep trying http://ithesis-ir.su.ac.th/dspace/bitstream/123456789/2977/1/60155902.pdf from time to time.

    It seems a fairly serious "internal  error" as it won't let me go to the home page or notify the administrator. With luck this might mean that they will fix it soon-ish (a few days?).

     

     

  6. On 7/29/2023 at 11:39 PM, Bill Kielb said:

    Just looking at this further, car mirror heaters might give us an idea of the energy required. If my quick math is right - temperature dependent - it looks like on the order of 1-2 watts per square centimeter.

    Just another data point: electrical heating film for underfloor or sauna heating @ 440w/sq meter.  https://tinyurl.com/2abs2xdf

    Didn't quite believe the difference in the wattage figures, so checked my maths.

    image.png.c87e5fa050942525f8d5b815d2aca40d.png

    The rather large difference maybe related to the speed of response required?

  7. 3 hours ago, bwerkheiser said:

    I was planning to fire at cone 6…. don’t have a personal kiln yet, but when I do, it will be electric, so I’ll be firing at cone 6.

    Be aware that kilns advertised as cone 6 may have a short element life if regularly fired to cone 6.

    In https://community.ceramicartsdaily.org/topic/30261-paragon-dtc-800-kiln/?do=findComment&comment=228238
    A cone 6 kiln firing to cone 6 will only get maybe 50 firings before the elements need to be replaced. Once they wear even a little bit, the kiln can no longer reach its max temp. In a cone 10 kiln firing to cone 6, the elements can wear a lot more before they need to be replaced. If your cone 6 kiln is getting more firings that that, then it is probably under-rated.

     

  8. On 7/29/2023 at 4:29 PM, Ahmad.khd said:

    Hello,

    I have an 80-meter nichrome wire and I want it to heat up to 40 degrees Celsius maximum (30 to 40 is ok). I want to connect it to a battery that is enough to make it hot for at least 10 hours.

    The ambient's temperature is negative 15 degrees Celsius.

    What is the diameter for this wire? what is the resistance? 

    What are the spec of that battery in this case?

    First a few caveats.

    1) As you ask what is the diameter of the wire I assume that you haven't got it yet. If so, why use expensive nichrome when you are operating it at such a low temperature? Oxidation of the conductor isn't going to be an issue, so nichrome's big selling point doesn't apply.

    2)  At the temperature you mention the wire looses heat  mainly through conduction and convection rather than radiation. These are very dependent on the (changing?) surroundings of the wire. 

    3) The amount of heat required to melt snow off the wall (I'm assuming the fabric is inside the wall) may significantly exceed that required when the outside conditions are dry. Do you have any guestimate of the weight of water that might need to be unfrozen? (It takes about 0.1 Kwh to melt 1Kg of ice once it's at 0C.)

    4) While it still needs careful engineering, I suspect that a thermostat-based solution would handle the wide range of conditions better.

    Then a reference from the Electrical Engineering section of a Q&A site
    How do i find nichrome temperature
    https://electronics.stackexchange.com/questions/84516/how-do-i-find-nichrome-temperature
    ... I rather go with the second answer

    You can't. Sorry.

    The temperature of the wire depends not only on the electrical power on this wire, but also on the ambient conditions - i.e. how the heat is dissipated. This way, the temperature of the wire will not be constant in time, but will change depending on the air temperature and movement, materials that are in contact with the wire and so on.

    In order to make the temperature constant you will need to make the ambient conditions pretty stable, or to use temperature regulator that to regulate the electrical power on the wire in order to get the same temperature in different conditions.

    As long as the theory behind such phenomenons is too complex, the calculations are actually possible, but very complex. In most cases, experimental way is much more reliable and useful.

    Simply use regulated power supply and change the wire current until the temperature becomes what you need. But always remember that in other conditions it will be different.

    PS I see that StackExchange have tags that direct heating questions to interested readers. Maybe posting there would give you a better answer.
    https://diy.stackexchange.com/questions/tagged/heating
    https://diy.stackexchange.com/tags/heating/info

    I've almost no personal experience with StackExchange, other than it's software section which is always informative.

  9. 1 hour ago, Kelly in AK said:

    There is something known as calcined borax available

    Interesting to know. Probably not an easily DIY-able process (unlike calcined alumina, kaolin, etc.) as seems to be melted & reground not simply pre-heated.

    Anhydrous Borax
    Alternate Names: Calcined Borax, Dehydrated Borax, Pyrobor
    https://digitalfire.com/material/anhydrous+borax
    Anhydrous borax is made by fusing hydrated borax into a glass and regrinding it.

  10. NASA seem to have had similar problems creating wind-tunnel models, there might be some interesting thoughts in:
    Improved ceramic slip casting technique https://ntrs.nasa.gov/citations/19940015904
    ... and the associated patent

    Not least the idea of using a shell mould (i.e. constant wall thickness).

    PS They seem to apply (paint?) the shell on a wax positive.

    If you prefer to cast it then a previous reference might be relevant
    3D Printing a Mold for a Slipcasting Mold
    https://www.instructables.com/3D-Printing-a-Mold-for-a-Mold/

  11. I'm not convinced that the shrinkage of the clay against the undercuts will not harm the casting, but ...

    Recycling of plaster of Paris
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7276351/
    Conclusions
    Plaster of Paris can be produced by thermal treatment of recycled gypsum powder at a temperature of 180°C for 2 h. The results of this project show that POP could be recycled repeatedly with the same procedure without altering the required setting time and working characteristics of recycled POP powder for prosthetics and orthotics, and even improving the compressive strength of casts. Thus, recycling POP could preserve the environment and reduce pollution. It seems that recycling POP could reduce the cost of importing new POP. However, further study is needed to compare the costs of importing versus recycling POP.

    ... remembering they were recycling dry plaster.
    ... and grinding it to a powder.

    In your case the firing cycle would have to be slow enough at the right temperatures to successfully candle the clay. Also you would need to dry out the plaster.

    PS Faint memory that maybe freshly made pieces can be candled faster/hotter than partly-dry ones.
    From https://community.ceramicartsdaily.org/topic/29727-candling-temperature-drying-greenware-in-kiln/?do=findComment&comment=227839
    What I certainly don't understand is a point I heard Ian Gregory make. That he could fire (without candling) pots a few hours after he made them, but otherwise has to wait about a week to do so.  A tentative guess is that a half-dry pot could have a dry (and thermally insulating) outer layer that lets the outer layer to become "too hot" before evaporative cooling kicks in, while a fully damp pot supports an evaporatively cooled interface  moving gradually from the outer surface inwards.
     

     

  12. I'm unsure that you can produce a plaster slip-casting mould with a lost-wax process. Wouldn't melting the wax contaminate the plaster surface?

    A highly speculative, but possibly relevant thread, relying on the thermal degradation of the plaster.

    @tkw954 Did you have any success?

    PS More details on the size and shape of your master would be helpful.

     

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