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  1. Like
    Textree reacted to Sputty in How did they do this ?   
  2. Like
    Textree reacted to Gabby in How did they do this ?   
    Ceramics supply stores have what are called texture mats. One can roll out a slab of clay with a rolling pin,  and then roll the slab on the texture mat or the texture mat on it.
    Peel them apart and, voila, you get a slab patterned like this.
    You can cut the slab to the shape you need and hand-build the pot.
    I have a pot coming out of the kiln today using this sort of texture mat, except mine is the sort where the areas that are gold here are the depressed areas rather than the raised ones.
    When I glaze it, I intend to use a glaze that breaks over texture, which is to say it will naturally show a different shade in the depressed areas than the raised areas.
  3. Like
    Textree reacted to Min in How did they do this ?   
    Another way you can do it with clay is to slip cast a piece using different colours of slip then carve through the layers. Examples of work done like this here.
  4. Like
    Textree reacted to Min in Choosing a clay for slip casting big pot   
    I really doubt the clay I used would be available to you, F78G from Plainsman Clay in Alberta.  Haven't used any clays from Armadillo and don't know if they are an option for you but their Buffalo Wallow looks like it could be tight enough with a posted porosity of 1.73  There should be someone on the forums who knows about their clays and/or other ones in your area. I would look for low porosity figures, some sand or grog for strength, the colour of the fired clay. I would just buy a bag to start with and run your own porosity and absorption tests on it before making the pot. Compress the clay slabs with a rib to push any grog or sand into the clay. If the unglazed clay is too rough you can sieve some slip made from the same clay and right after rolling and compressing the slabs brush a couple coats of slip on the slab. 
  5. Like
    Textree reacted to Min in Choosing a clay for slip casting big pot   
    Is this going to be a rectangular bonsai pot? If so it wouldn't be difficult to make from slabs. I've made a few really big planters this way. Thick slabs, like 3/4" thick made from a super coarse clay, let them stiffen up  then miter the joins and slip / score. No molds or forms or special equipment needed.
  6. Like
    Textree reacted to Chilly in Choosing a clay for slip casting big pot   
    Hi Textree
    I would definitely make a first try with a hump mould.  You need to make a "master" anyway, before you can make a slip mould, so you might as well.
    Clay will release from untreated wood but I usually line with thin plastic as it makes it easier.  Place your hump mould on a block so the rim is not touching the table, then you can get to the rim of your pot and cut it off level.
    I have made many large bonsai pots, I've used all methods except throwing.  Slip-casting, slump, hump, coiled free-form, coiled inside a biscuit tin, slab-sided, bricked.  Unless I was going into production I would not be wanting to make a slip-casting mould.  Too much time and effort, too heavy when empty, far too heavy when full.
    The cast-iron Owl below is 12 inches tall, and the mould is too heavy for me to lift when full.  I can just about slide it around on the table, when ready to tip.  If you do go for a mould, a plug for emptying is a must.

  7. Like
    Textree reacted to Sputty in Choosing a clay for slip casting big pot   
  8. Like
    Textree reacted to douglas in Choosing a clay for slip casting big pot   
    Since you are making the original model out of wood, you might be better off using a hump mold and slabs vs. trying to master slip casting. I know you are not proficient in clay, but using a slab and hump mold is pretty easy even for beginners. There are plenty of youtube tutorials you can watch, but here is a quick read to get the idea. 
    This way you are only paying for clay, glaze, and firing fees. You would probably need to use several large slabs since rolling a huge slab like that might be difficult. 

  9. Like
    Textree reacted to Sputty in Choosing a clay for slip casting big pot   
  10. Like
    Textree reacted to neilestrick in Choosing a clay for slip casting big pot   
    Plaster should be cheaper from the pottery supply place. Should be around $20 for 50 pounds.
    Make sure your form is totally smooth and clean, and well sealed. Plaster will stick to wood pretty easily if there's any sort of grain texture. The more time you spend on the form, the less time you'll have to spend on cleaning up the clay piece. That's why for a one-off piece it might be faster and easier to hand build it rather than casting.
  11. Like
    Textree reacted to neilestrick in Choosing a clay for slip casting big pot   
    There are casting slips available that you can buy ready to go. I believe Standard Ceramic is one source. Otherwise, you can take any commercial body and make it into a casting slip. If you can't buy the clay body as a dry mix, then you'll need to buy moist clay and let it dry, then break it into the smallest pieces you can before making slip with it.
    If you're just planning on making one or two of these pots, I would slab or coil build it. A mold that large is a big undertaking, and IMO not worth the effort for one or two pieces, especially if you're new to mold making and slip casting.
    Here are my calculations for the volume of plaster you'll need, for #1 pottery plaster:
    Your piece is 18x15x5 = 1350 cubic inches
    If you make the mold 2 inches thick all around, that's 22x19x9 = 3762 cubic inches.
    Subtract the volume of the piece from the volume of the outer mold, and that leaves 2412 cubic inches of plaster to make the mold.
    You need 16.312 grams of plaster per cubic inch so 16.316 x 2412 = 39,354 grams of plaster. Divid that by 454 grams/lb and you get about 87 pounds of plaster. That's a big, heavy mold. You'll need almost 6 gallons of slip to fill it, so that's another 70 pounds or so added to the weight of the mold when it's full.
  12. Like
    Textree reacted to neilestrick in Choosing a clay for slip casting big pot   
    If you can make it work, it'll be an impressive pot that you could perhaps make more of and sell. I just think that if you're not an experienced mold maker and slip caster, a mold that big would be very difficult to make, and even more difficult to handle when it comes to the actual casting process. I would start with something much smaller, to familiarize yourself with the process, and see if going that big is something you're truly comfortable with. Things get complicated as they get big. I've made a number of molds, and taught my students how to do it, but I personally wouldn't feel comfortable tackling something that big without more experience.
  13. Like
    Textree reacted to Mark C. in Choosing a clay for slip casting big pot   
    You will find a mold that big will have its own issues due to weight.Neil summed it up well in above post. Molds that large are problematic due to size and weight . Start small and work up. Same way with knowledge and experience.
    One tip I can add if you do make a mold that big is sandwich it between to large round pieces of plywood that roll -that way you can drain it easier.
  14. Like
    Textree reacted to Sputty in Choosing a clay for slip casting big pot   
  15. Like
    Textree reacted to bciskepottery in New Want To Make A Pot   
    First, even though my climate is subtropical I want it freeze proof. I think that means 100 percent vitreous. Am I correct in thinking that means I have to do stoneware or porcelain fired to cone 10 or higher?

    As long as you fire the clay you choose to vitrification, it does not matter if it is cone 10 or cone 6 or earthenware. Find a claybody -- stoneware or porcelain -- that has an absorption rate of 1% or less at the temperature you fire or the community studio fires. If the studio fires to cone 6, then use a cone 6 clay; do not use a multi-range clay (cone 6 to 10) and fire at cone 6 -- that pot will not be vitrified.

    Next the pot like I said will be pretty big I am thinking very simple round with straight walls but diameter after firing will be 17 to 19 inches. If I use porcelain or high fire stoneware is it safe to assume it will even fit in the their kiln? Will they let me over fire to say cone 11? Can most kilns get that hot? Their website says you can pay for studio time hourly if you have demonstrated skill. Does that mean they'll want me to take their classes?

    Ask them what their kiln size is. Some are 7 cu.ft. with a 21" shelf; some are 10 cu.ft. with larger shelves. The key will be to have it fired on a whole shelf, not two half-shelves. During firing, your pot will both expand and shrink -- it moves on the shelf while doing so. So, a whole shelf will reduce the potential for any warping; half-shelves may expand and contract slightly differently, heat and cool at different rates, and increase the potential for warping.

    Most studios want to see what a potter knows before letting them loose. Mostly they want to see work habits, e.g., do you clean up your messes, do you use any dangerous tools, etc. The easy way to see that is by requiring a potter to take a class. They want to see how you glaze and are careful to avoid glaze runs in their kilns. Or you make wares that dry completely and don't blow up in the kiln -- damaging other potters works.

    And finally any other tips or comments? I've looked at some videos online, maybe I am being naive but I think it looks pretty easy to make a round pot on a wheel.
    Go for it.  It will be a challenge but worth your effort to have your tree growing in your vessel.  Even if it does not work out, you will have a better understanding of what makes a good bonsai vessel made by others so if you do buy from another potter, you will like your vessel even more.  One of the more helpful things I've done is taken an ikebana class so I could better understand how they used the vases -- and it was worth the weekend investment in time. 
  16. Like
    Textree reacted to mdobay in New Want To Make A Pot   
    Very interesting post..  As some have already commented and although making something on the wheel looks pretty easy the fact is for most it takes many hours/years of practice, but I think all the long hours and years of practice is to perfect or hone their skills and to be the best that they can be for  love of their craft. So I guess what I am getting at is that yes you should take that class and at the minimum you will understand the process.. My guess is that a good teacher could probably help you make that pot. It may not turn out to be a very well thrown pot! but it will be something  you made and that's what's important for you.. I would say GO FOR IT and enjoy the process of learning, we all started somewhere!
  17. Like
    Textree reacted to Denice in New Want To Make A Pot   
    I think beginners should start out with slab, coil, and pinch pots and you could make your self a nice oval pot bonsai planter with the slab or coil method.   Take the class and see if you like working with clay and work with your teacher in choosing a clay for your planter.  Denice
  18. Like
    Textree reacted to Stephen in New Want To Make A Pot   
    I vote for coil building it like Denice suggested, that you could actually do that after a little instruction. It probably will not be thing of beauty but it will be big and hold that tree and like you said you can say you grew the plant and made the pot. Coil building is also something to master as well if you decide you like slab pottery but not wheel throwing u can go that way.
    yeah you are being more than a little naive, but that's OK, lots of people approach wheel throwing having no idea its as hard as it is to get good at and the folks that are really good make it look so damn easy :-)
    I applaud your "I can do anything attitude". The wheel is something that stops a lot of folks interested because it usually takes a lot of hours of failing miserably before you can produce anything at all and popping out a 2 foot pot in your first year or two of throwing is probably wishful thinking.
    BUT maybe you will master it very quickly, go for it and be patient if it seems like its taking forever to get the hang of it because that is more the norm than those that master it quickly.
    Anyway, good luck with your project and have fun!
  19. Like
    Textree reacted to Chris Campbell in New Want To Make A Pot   
    Start by looking up Mark Issenberg at Lookout Mountain Pottery for a ton of ideas about making Bonsai plant pots ... Follow him on Facebook as he posts a lot of images of them too. Fun site that will inspire you to go for it.
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