Jump to content

Search the Community

Showing results for tags 'bubbles'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • Ceramic Arts Daily Forums
    • Forum FAQ & Terms of Use
    • Studio Operations and Making Work
    • Clay and Glaze Chemistry
    • Equipment Use and Repair
    • Business, Marketing, and Accounting
    • Educational Approaches and Resources
    • Aesthetic Approaches and Philosophy
    • Int'l Ceramic Artists Network (ICAN) Operations and Benefits
    • Ceramic Events of Interest

Find results in...

Find results that contain...


Date Created

  • Start

    End


Last Updated

  • Start

    End


Filter by number of...

Joined

  • Start

    End


Group


AIM


MSN


Website URL


ICQ


Yahoo


Jabber


Skype


Location


Interests

Found 10 results

  1. I hand-mix a transparent glaze, which I've used for the last year continuously with great success. The last two times I've glaze-fired, TONS of little bumps appeared, a few of them up to a cm wide (those ones looks a little more like an air bubble in the clay. The clay is white and the glaze is clear, but the bubbles that are appearing are white (so it looks like the glaze has fused to the clay body and pulled it out into bumps/bubbles. Please see the attached photo- this is what all my pieces came out like. I thought my glaze might have been contaminated so I mixed a whole new batch but the same thing happened. The only other thing I can think of that might be different is that it's more humid in the studio because it's the middle of summer. Please help! I'm getting so delayed on my orders because I keep having to re-make everything and I'm freaking out! Should I try re-firing the pieces and doing something differently, like holding it a bit? I fire my bisque to cone 06, and the glaze to cone 6. The kiln sometimes runs a little on the hot side, but I haven't found that to cause this particular problem before. I use PSH cone 6 white stoneware #519. My glaze recipe is: 25% epk, 25% silica, 10% wollastonite, 25% frit 3134, 15% feldspar minspar. Thanks in advance!
  2. I have recently fired a cone 6 faux celadon glaze and ended up with crackle on some pieces and tiny bubbles which have produced a cloudy appearance on others. Can anyone say why I may have gotten two different results in the same firing. Here is the recipe if that will help... Birk's Turquoise Custer feldspar 58 Cal. carb. 17 Silica 14 OM4 (ball clay) 6 Zinc oxide 5 Copper carb. 1 Thank you! :)
  3. Hi guys. I've started my aquaitance with ceramics and glazes half a year ago. I still have a very basic understanding of chemistry and I have several problems I'd like to ask about. First is clear transparent glaze. I made around 10 of them taking different recipes, but all of them contain bubbles. I've tried bisque firing in various temps, from 600 to 950C and second firing slow cooling, dropping and slow cooling, but bubbles are there and their quantity is similar in all conditions. I know commercial glazes don't have such problems. Please help me to figure out what is going on. My thought is that my raw materials are the problem. I have very few materials for glazes, those are: feldspar, whiting, borax, dolomite, talc, silica and kaolin. Substituting whiting with wollastonite didn't help. The runnier the glaze the less bubbles it has, but running is provided with whiting and borax and I have white clouds coming along with bubbles. Less flux - no clouds, but still bubbles. I imagine it is kaolin that gives a lot of small bubbles. Any chances to fix that? I have stains and wish to use them in underglaze painting, so I need to make a decent covering glaze. For underglazes I bought a few frits, I don't know their formula, seller keeps it in secret, only mentioning temp range. I have 1 lead flux frit melting on 710C and other leadless on 1100C. I need to fire on 1220C, so I guess some kaolin may help to lift temp of frits melting so the stains won't burn out, but more bubbles again? If you have info how to win the fight with bubbles please share. Sorry if made any mistakes.
  4. Maj0rMalfunct10n

    Cone 06 - Mayco Dry Mix Glaze

    Hi, I fired my kiln yesterday and I received some mixed results. I follow a fairly strict process when firing my kiln (usually takes 8 or so hours) and have had good success in the past. I don't mix my own glazes yet, and use dry mix from Mayco. In this fire i received a fair amount of bubbles in the glaze. I have attached a few photos. I was wondering if this is a symptom of overfiring? I am sure this is ceramics 101 but any input would be great. thanks ~Mal
  5. Hello, I'm new to these forums and would appreciate some help! This isn't a new problem but I still don't know what causes it. On this particular problem piece, I used: Flint Hills "Porcelain" ^5-6 slip made with mason 6308 (Delphinium) mixed with the Flint Hills clay body Amaco HF-9 Clear Glaze. I do an 8-10 hour bisque to ^04; glaze firing is ^5 or ^6. I'm attaching a photo that shows a sample of bubbles that formed all along the edge of this platter. It happens most often on blue underglaze or slip, but I've had the problem with other colors. Sometimes a mug's rim will come out all bubbly and rarely the bubbles are on the main section of the piece. I dip glaze my work and carefully smooth out any pinholes or bubbles - and as far as I can tell, THESE bubbles along the rim are not visible before firing. Everything else in the kiln with this platter came out great! Here's what I've done so far: I've tried other colorants - several blue underglazes from Amaco & Mayco. I tried clay body slip with mason stain. I've tried other clay bodies. I slowed my bisque time to 8-10 hours. Called Amaco, but they weren't able to help. Does this look like out-gassing that didn't complete during bisque? Do larger pieces require longer bisque firings? Do you have a clear glaze recipe or suggestion that might "fix" it? I'm really hoping you all can figure this out - offer some advise or a solution (yes!) Usually it happens on platters that I've spent hours carving (I sgraffito the work) and I'm so frustrated and tired of re-making work - Please, can you offer advise or a solution? Thanks so much! Carol R
  6. synj00

    Bubbles!

    Hey everybody, been doing some testing and went through my first gas firing. (click my sig link if you are interested in the firing) I thought it was a disaster but others tell me not so much. Expectations will absolutely RUIN your happiness. Anyways, I have 2 glazes that I really kinda dig. The first glaze is a leach white which is nice and I'm still doing some tuning on that. Below is an example of the leach 4-3-2-1 glaze that went through the gas firing with too much reduction and made it to cone 9. I put a sprinkling of FE203 Red Iron Oxide and a sprinkling of Rutile as well just to see what each would do. The second glaze is what I'm curious about. It's Malloy Clear. Its not really clear, its opacity is created by billions of bubbles trapped in the glaze which is actually quite cool. It gives it a warmer color and I'm quite smitten. Being that there are bubbles in this, and they do not affect the surface of the piece would these be in any way compromised in strength / durabiltiy / foodsafenes etc?
  7. Is it possible that particularly virulent bacteria continued to respire in the drying slipware? if yes, would that show bubbles burst at the surface visible to me before firing, or not, I wonder? I made my own porcelain paper clay slip with porcelain powder, dispex, tissue and water. It's worked before but I left this one and it stank. following instructions from tutor I added a bit of bleach but the bleach didn't completely kill whatever it was, not totally. It was grey in colour. I poured vessels, they looked fine (but the smell and grey colour lingered until they were totally dry). Biscuit showed no signs of any problems. But stoneware temp and they've come out looking really vile, absolutely completely covered in small irregular bumps. I've broken them open and it's clear air pockets near to the surface predominantly. I can't see that this was clumped paper fibre as most of the gas holes are smooth in shape. It was a well mixed and as bubble-free as a liquid as I would usually have it. Therefore any burnt off paper could have escaped through usual channels. HOwever, if the paper gas could escape then why not this gas (if that's what it was)? Is this just a matter of something going too hot? many thanks.
  8. From the album: Curt

    bubbles on the bottom of a commercial dinner plate whiteware. bubbles are smaller and somewhat more dispersed, but still visible as small spheres. 200x magnified.
  9. From the album: Curt

    spherical bubbles in a transparent glaze fired cone 10 oxidation. dark blemish on otherwise white porcelain gives some additional contrast to show bubbles. 200x magnification.
  10. From the album: Curt

    spherical bubbles entrained in a transparent glaze fired on porcelain in reduction cone 10. The eight white lights visible in the centers of the bubbles are from the 8 LEDs which the USB microscope uses to light up the subject matter under inspection. 200x magnification
×

Important Information

By using this site, you agree to our Terms of Use.