vince pitelka on sun 11 nov 01
> Dannon, can you stick the canvas bats to wood and masonite? Do you stick
> them down with wads, or a large pad, or??
> Thanks---- Gail
Gail -
This was a technique Dannon learned from me, and I have spoken of it on
Clayart before, so I'll repeat it here. Get heavy canvas, or preferably
oilcloth. The latter is pretty hard to find these days, but it works best.
If you can't get oilcloth (oiled canvas) then just get painters canvas at
least 10 oz. weight. Cut it into squares with a diagonal measurement at
least twice the base diameter of the forms you wish to throw. Obviously you
may wish to make an assortment of sizes. I use canvas only for small and
medium items, but as you can see from Dannon's post, you can use it for
large things as well.
Stop at a hardware store and buy the cheapest triangular mason's trowel you
can find. If possible, get several sizes.
Mix a quart or so of gritless slurry with kaolin if you are throwing
porcelain, with goldart if you are throwing stoneware, and redart if you are
throwing terracotta. Moisten the canvas squares with water and paint both
sides with a thin coat of the slurry. Let the squares dry completely. You
will only have to do this to the brand new canvas squares, because there
will always be residual slurry on the canvas after each use. The canvas
squares must always be completely dry before use, and there must be residual
slip on the surfaces in order for them to grab onto the wheel.
When ready to use the squares, spread a thin spiral of the same slip in the
center of the wheel or bat (doesn't matter if it is the metal wheelhead or a
wood or plastic bat) with your fingertips. You cannot use a slip which has
sand or grog in it, because the grit will act like little ball bearings and
the canvas square will slide right off the wheel. Press the canvas square
down over the slurry, and use one of those stiff black kidney-shaped rubber
ribs to seal the canvas down securely by smearing outwards in all
directions from the center of the canvas as the wheel rotates slowly.
Throw on the canvas surface just as you would the wheelhead or bat. When
the pot is done, stop the wheel and carefully pull your cutoff wire UNDER
the canvas. This is where heavy canvas really pays. If you try to use
thinner canvas, it will wrinkle and bind when you try to pull your cutoff
wire under the canvas.
Grab one corner of the canvas, and pull the pot onto the mason's trowel, and
transfer to a wareboard, and pull the pot off onto the wareboard.
Scrape the residue off the wheelhead, smear a little more slurry on, apply
another canvas square, etc. If you do not scrape the residue off the
wheelhead it will be more difficult to pull your cutoff wire under the
canvas.
When the wares are leather hard, peel off the canvas, smooth the burr around
the edge with your fingertip, do a rolled edge if you wish, and you are done
with the bottom.
Good luck -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
Gail Dapogny on sun 11 nov 01
Dannon, can you stick the canvas bats to wood and masonite? Do you stick
them down with wads, or a large pad, or??
Thanks---- Gail
>Indeed, Cindy, they DON'T warp. Or at least, if they
>do they flatten right back out again when you put the
>canvas down. I do this all the time, with no problems.
>For really large pieces, platters 20" or so, I leave them
>on the bat and draw the wire tool UNDER the canvas.
>Works fine. Soon as the rim is ready, I turn them over
>onto a bat, and peel off the canvas. Perfectly flat foot,
>makes trimming easy. I recommend canvas bats for
>nearly any large piece, bowls and all. If you've already
>got plaster, it works fine. If not - well, canvas doesn't
>take up much room, and is cheap and extremely long
>lasting. Easy to make - I tear to the right width, then
>across to make squares, cut the corners off (I don't like
>them to flap around). If they're smaller than the bat,
>I don't cut the corners. If the bats are really bit, 20" or
>more, I take the trouble to make round ones. There is
>no reason for that, it is just what I do.
>>regards
>Dannon Rhudy
Dannon Rhudy on mon 12 nov 01
Gail asked:
>Dannon, can you stick the canvas bats to wood and masonite? Do you stick
>them down with wads, or a large pad, or??.........
The canvas will stick to wood or masonite. Once you have made
a canvas bat, dredge it in dry clay, any will do. Moisten the bat
with a sponge, and just lay the canvas on. Smooth it out if there
are any wrinkles. The clay in the canvas is what makes it stick
to the bat. Thereafter, DON'T CLEAN THE BAT. That is, don't
wash or rinse it - it needs the clay in it to stay neatly on the wheel.
If there are large clumps of clay on it, scrape those off, but
otherwise, leave it alone. Don't use a lot of water putting the
canvas on the bat/wheelhead - too much will make it slip. Just
try it - you'll quickly see what is required. If you don't have
any dry clay around, then I expect you could dip the canvas
bat in very thin slip, wring it out, let it dry - it's ready.
regards
Dannon Rhudy
Dannon Rhudy on mon 12 nov 01
....... how do you pick up the large
>plates (not the 20 inchers, but the ones you don't
>use a bat for) without them sagging all over the
>place? You must have some canvas hanging over.......
I pull a wire beneath the canvas to loosen it from the
wheelhead, and just pick it up by opposite corners
of the canvas, sit it on the wareboard. I seldom have
the foot of the plate as wide as the bat. Sometimes
I slide my hand under....depends on the size of the
piece. I had to think about that, when you asked.
Habits are so....ummmm....habitual.
regards
Dannon Rhudy
Lorraine Pierce on fri 7 dec 01
Hi Vince. I cut and prepared a couple of canvas bats following your
directions and I LOVE using them....when I think of all the time and mess
and expense of molds for my plaster bats, plus the weight of the bats in my
arthritic hands...!! I'm off to buy canvas today. When you specified
painter's canvas did you mean artist's canvas for paintings, or drop cloth
canvas for house painters?
One more question...since you prefer the impossible-to-find-now oilcloth,
would a coating of polyurethane on one side help? I believe that is now how
people making floor cloths treat the canvas carpets they paint.
Thanks Vince. Lori in New Port Richey, Fl.
vince pitelka on fri 7 dec 01
> arthritic hands...!! I'm off to buy canvas today. When you specified
> painter's canvas did you mean artist's canvas for paintings, or drop cloth
> canvas for house painters?
Lori -
Either would work as long as the canvas is heavy enough. I have always used
artist's canvas - at least 10 oz. canvas duck, easily available from any
good art supply, but much cheaper if you can find it at a yardgoods store.
> One more question...since you prefer the impossible-to-find-now oilcloth,
> would a coating of polyurethane on one side help? I believe that is now
how
> people making floor cloths treat the canvas carpets they paint.
I have never tried that, but I bet it would work slick as can be. It would
be essential that you preserve the coating of slip left from the last usage,
and squeegee the canvas squares down very quickly, so that the excess slip
is expelled and the moisture in the thin remaining layer of wet slip is
sucked up by the residual dry slip on the canvas square, giving a very
strong bond to the wheelhead. If it works with the oilcloth squares I have
been using for 25 years, it should work with canvas coated with urethane.
If you give this a try, let us know how it turns out.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
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