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cf66

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Everything posted by cf66

  1. Hi all, I'm new in this forum and would appreciate some wisdom on figuring out shrinkage rates. I'm working with Laguna B-mix Cone 5, which as per Laguna has: Avg. Shrinkage 2±%: 12% Avg. Water Absorption 1± %: 2.3% COE x 10-6: 5.74 (note: no idea what COE is. Do you?) Now, what exactly is this 12% shrinkage? Is it the shrinking after both bisque and glaze firings? (I bisque at cone 06, glaze at cone 5). What is the shrinkage from wet to bone dry then? Does this mean, for example, that if I want the drain hole in the sink I'm trying to build to be a finished size, that is, after glaze firing, to be 3.175 cm (which is 1 1/4", I'll use cm since it's simpler for calculations, being decimal and all...), at WET (plastic) stage the hole will need to measure 3.60 cm, where 3.175 cm is 88% (100% - 12% shrinkage rate) of 3.6 cm? Am I figuring this correctly? Where does the 2.3% water absorption rate come into play? Is that the shrinkage that happens from plastic/wet stage and bone dry? If the posted avg shrinkage rate is 12%, how much of that shrinkage happens after the bisque firing and how much after the glaze firing? What happens if, for example, I need to do a second glaze firing, will it shrink even more? And what happens if that second glaze firing is not at the same temperature as the first glaze firing, let's say it's for decals at cone 012? I need to be really accurate for the pipes and hardware to fit correctly on this sink. I'm confused. I'll thank you in advance for any light you can shed on this for me...
  2. cf66

    Critter Spray Gun And Air Compressor

    Thank you, Mark!
  3. cf66

    Critter Spray Gun And Air Compressor

    Hi Mark, Since my dipping technique really sucks, I want to start spraying my glazes (never tried it) and I'm really disoriented as to what compressor to get. I've read every thread about it here and yours interested me because I can't have a noisy compressor and it sounds like yours is the ticket - nice and quiet. The only thing I wonder about is the CFM/psi specs. That Senco 993808 you recommend, is it powerful enough to spray pieces the size of a bathroom sink nice and evenly, say? (the end result should look like dipping). I gather I need to use a HVLP spray gun for that (as opposed to an airbrush? If that's the case, I'm buying it NOW!! Please let me know when you get a chance (the sooner the SO much better!! ) Thanks so much!
  4. Hi all, I'm just in love with this look and wonder how it's achieved: with underglaze over a white glaze? dipping a powdered (undiluted) mason stain over the wet white glaze? with drops of water on underglaze applied over wet white glaze? a cobalt oxide wash? Anyone?? Thanks!
  5. cf66

    Slip And Crochet

    This is what I've been wanting to try for EVER!! Thanks so much for posting your experience and results. I've had a gallon of Laguna Porcelain Slip sitting in my studio for a few years now (three? maybe even four?) and I'd like to know if I can still use it, and if so, whether I need to do anything to it (like add deflocculant, or whatever). What I also want to do is coat some sheets of fiberglass mat ( http://www.homedepot.com/p/3M-Bondo-8-sq-ft-Fiberglass-Mat-20129/202077814?keyword=fiberglass+mat) that I will be forming with, instead of the cotton yarn. I'm all ears to any words of wisdom. Thanks in advance!
  6. cf66

    Fusing Glass With Clay

    Hi all, Does anyone know if it would be at all possible to fill into cracks with glass? Think Kintsugi,, sort of... I would like to try filling into tension cracks in some "failed" cone 6 pieces with glass. Anybody?
  7. cf66

    repairing grenware?

    I was afraid that would be the answer... Well, I did it. Let's see how it fires when it does! Thank you guys so much for all the suggestions!
  8. cf66

    repairing grenware?

    Thank you! And by the way, I'm actually having the exact same problem as Chris above: crack at a joint (and probably even for the same reason!). I'm posting a picture to better illustrate it. The thickness of the wall and bottom is 1/2". I'm not too clear on how to go about applying the mixture to it, since it's not a case of joining two separate pieces. How much to moisten and how, with an eyedropper right over the crack, for instance? And then push the mixture into the crack? I don't want to make it worse... it would be great to salvage this piece.
  9. Hi all, I want to try a formula for a ^5 gold glaze (it says 1230-1260 C, I suppose that's still ^5 ?) called "Gold Pigment" out of an old Ceramic Review issue, and I'm not sure what are the US equivalents to the UK materials the formula calls for. The entire formula is: Manganese dioxide 43 Copper oxide 5 Cobalt oxide 5 Red clay 57 Ball clay 4 Quartz 5 So what red clay? Redart? Which of all the different ball clays we have in the US?? If I use Silica 325 is it the same as the quartz this formula has? Is flint also the same as quartz? Also, another formula, a ^4-7 bronze, calls for china clay. Is it the same as kaolin? And to continue giving away that I know NOTHING of glaze formulation: how come this formula when added up is over 100? Thank you in advance for any wisdom you can send this way.
  10. Hi Steve, Would you be so kind to share a successful firing schedule for your saturation gold glaze? I will be using it on stoneware (Laguna B-Mix 5). And I will first dip it into a glossy white, is that what you would suggest before brushing the saturation gold on? Thanks so much.
  11. Thanks, guys! This formula is called "gold pigment" (it's supposed to be used as a glaze but technically speaking it's considered a pigment) and I want the most metallic gold look possible. If you have any recipes that would do this, I'm all ears!! I would love to get a successful firing schedule for it... anybody has any idea? It's for cone 5.
  12. cf66

    repairing grenware?

    Marcia, you're saying to just add toilet paper to the spooze recipe from TJR?
  13. Hi Steve, I used Saturation Gold on a couple pieces made with Laguna's Cone 5 B-Mix With Sand and although still beautiful, it came out all blistered. I used the "slow glaze" program on my L&L Easy Fire kiln with a 3 hr "preheat", as it calls it, for a total of 12 something hours to fire at cone 5. Both pieces shown in the pictures are made with the same clay body. I now see from your post that I shouldn't have done that 3-hr soak After reading everywhere how it needs it to be applied as a thick bunch of coats, I brushed a crapload of coats on them... Is there anything you can suggest to get a smoother result without the blisters? Thank you!
  14. Hi all, I handbuilt something that won't fit in my kiln lying flat (as in image) and wonder if it would work to fire it standing it on its side instead (my kiln is 21" round so it would fit that way). It's 20"W x 20"D x 4"H (wet) and made from slabs which I rolled in every direction (with a rolling pin) and joined with magic water slip. It's almost two entire bags, which means probably about 40 lbs wet. The slabs are about 5/8" thick (wet). I used Laguna B-mix with grog, cone 5. What would happen if I fire it standing on its side without supports? Will it actually need supports? If so, do they need to be fully vitreous or can they be just bisque? Or can they be just greenware like the object itself? Or should they be metal, and if so what kind of metal? What shape should they be and how should I place them? (If you look at the images, the round part is hollow, FYI). This is my first time ever building something this large so I would very much appreciate any info anyone could send my way and thank you in advance!
  15. Thanks, Mark. It's actually cone 5 and it's with grog, which I thought would make it less susceptible to warping (on the Laguna site it's described as "more forgiving"), but regardless, both WSO and Big White are for cone 10 only which I don't do.
  16. oyyyyy... you're so right, I need to lay it on something that lets it contract while drying!! Problem is, it's still pretty damn wet and it's so heavy, I honestly can't think how to move it onto newspapers Any ideas? And thank you so much!
  17. Thank you, Benzine! Can you recommend any good book or source of information on this subject? Meaning, how to support large objects during firing, building firing supports, etc...
  18. Sorry all, I just couldn't find how to delete the post, hence the empty space... my apologies. (If anyone can point me to how to delete a post, I'd love to find out!).
  19. cf66

    need help on glaze problem

    I have the same problem, and I too think it's because the glaze may be too thick, although it has the consistency of buttermilk (thicker than milk, thinner than heavy cream). I'm afraid of adding too much water and ruining it (I have no dry glaze left). Pres, can you please clarify the "no color coming through-the cuticles" part of your explanation? I think understanding this distinction might help me. I feel the adjustment in water content I need to make needs to be so carefully to avoid ruining the glaze! Thank you...
  20. oh thank you, that article is fantastic!
  21. I used a rolling pin to make the slabs (turning the slab 90 degrees each time, so they got rolled in all 4 directions). Each set of tiles came from one single piece of clay cut from one single bag for each clay body, on the same day (within less than an hour for all 4 different bodies and pieces thereof). I even compressed each tile with a rib after rolling them (now not 100% sure I compressed ALL of them but for sure some). And yes, I am measuring between the fine lines, some I even made 20 cm long in an attempt for better shrinkage representation/accuracy. And agreed on the curve-ball aspect of ceramics!! God help me at the time of making my actual product. Given this, I now basically can't understand how any mass production of identical items is possible, even though it clearly IS possible as proven by the billions of identical mass-produced ceramic items that exist in the world!!
  22. Hi all, OK, so just when it seemed all clear and resolved, turns out my test tiles of the same clay body at bone-dry stage have shrunk at different rates (yes, same clay body)!! I have made 2 to 3 tiles of for each of the 4 clay bodies I wanted to test, each is a slightly different thickness and size. For example, my three Laguna BMix cone 5 tiles have shrunk 6.25%, 6.8% and 6.7% respectively. My two Laguna Steve's White cone 04 tiles have shrunk 5.4% and 4.83%!! They're now being bisque-fired, we'll see how it all ends... Any thoughts, anyone?
  23. Thank you all, your replies are very useful info!
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