Anne Doyle on thu 17 apr 08
Help!
i've tried a search of the archives and read plenty on plaster for
slipcasting molds but i am more interested in hearing from people who made
their own bats using the pure and simple or similar systems... which
plaster did you use? there are too many to choose from at my suppliers and
i'm headed there in the morning so hopefully this will get some kind of
response ... if not it'll be like most things trial and error and we hope
not too much error...
Basically i could choose from :
pottery plater #1,
casting plaster,
K-59 plaster,
Fast cast,
white Hydrocal,
FGR-95 Hydrocal,
Dencast
Ultracal,
Hydrostone
Tuf stone...
ideally i would like them to be a bit absorbent so i could avoid wiring
off the bats and have the items pop off, but not with a totally dry rim
either... one type of bat i have tried draws so much moisture out of the
pieces that by the time they come off the bats without cutting off, the
rims are too dry to attach any kind of handles to them...
As always help is greatly appreciated and i will report back on the
results...
Also, if anyone has instructions for mixing the plaster that are fool-
proof (idiot-proof would be best) i would also appreciate that...
Thanx a bunch in advance,
Anne
John Rodgers on fri 18 apr 08
Anne,
Use the same as what is used in slip casting molds. US Gypsum #1 Pottery
Plaster. Mix the plaster 1 pound of water to i-1/2 lbs of plaster.
Sprinkle the plaster into the water, not the other way around. I use the
same bat making system, and it takes a 10 pound water/plaster mix to
make one 14 inch bat. - That is 4 lbs of water to 6 lbs of plaster. I
have used my plaster bats and the system for 8 years and wouldn't want
to use any thing else. Plaster bats are great in my book.
Regards,
John Rodgers
Anne Doyle wrote:
> Help!
> i've tried a search of the archives and read plenty on plaster for
> slipcasting molds but i am more interested in hearing from people who made
> their own bats using the pure and simple or similar systems... which
> plaster did you use? there are too many to choose from at my suppliers and
> i'm headed there in the morning so hopefully this will get some kind of
> response ... if not it'll be like most things trial and error and we hope
> not too much error...
>
> Basically i could choose from :
>
> pottery plater #1,
> casting plaster,
> K-59 plaster,
> Fast cast,
> white Hydrocal,
> FGR-95 Hydrocal,
> Dencast
> Ultracal,
> Hydrostone
> Tuf stone...
>
> ideally i would like them to be a bit absorbent so i could avoid wiring
> off the bats and have the items pop off, but not with a totally dry rim
> either... one type of bat i have tried draws so much moisture out of the
> pieces that by the time they come off the bats without cutting off, the
> rims are too dry to attach any kind of handles to them...
>
> As always help is greatly appreciated and i will report back on the
> results...
>
> Also, if anyone has instructions for mixing the plaster that are fool-
> proof (idiot-proof would be best) i would also appreciate that...
>
> Thanx a bunch in advance,
> Anne
>
> ______________________________________________________________________________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, change your
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>
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>
>
>
Pfeiffer Fire Arts on fri 18 apr 08
----->>>> Which plaster did you use? >>
We use Pottery Plaster. It is the best we have found. Hydrocal is very
strong, but it is slow to dry and heavy. Initially we used the formula on
the package or the web (exact water and plaster). Sift the plaster into the
water -- we use a wire food strainer. It will take a few bats before you
get used to the amount you need for your particular bat mold. You mix for
about 3 minutes then pour. Work quickly as it will begin to setup rapidly
and you will need a little time to adjust your mold top, et cetera. If you
lookup who makes your plaster you will see the exact numbers but we found
that after you do it a few times the water is all you really need to be
accurate with. Too little mixture and the bat will not sit flat, too much
and you get a mess to clean up.
We don't measure anything but the water any more. We sift the plaster into
the water until it will not get wet but just sits on top, then mix for three
minutes. We found it best to put an old plaster bat on top of the mold to
hold it down since the pressure needs to be very even throughout. We coat
the clean mold (and anything you put on top of it) with silica spray so it
slips right out and is easy cleanup -- also helps to protect the plastic
during the curing process. I am sure other things could be used but I know
silica works well. If you do not do this the plaster will stick to the mold
after a few bats.
There is quite a learning curve to making a good bat so do not give up on
the first few, you will get better. Watch that the top is all the way down
but not below of guide edge or your bat will not be level. Remove from mold
after about 20 min's and trim the plaster that comes out of the top holes.
The longer you wait the harder to trim. Two of the holes line up with the
bat pins and will need to be drilled out in most molds.
Hope this helps. We learned the hard way ---- GOOD LUCK!!!
Dan & Laurel in Elkmont Al
www.pfeifferFireArts.com
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9:30 AM
Anne Doyle on sat 19 apr 08
Many many thanx to all the kind folks who wrote to me on this matter on
and off-list...,
the help was greatly appreciated as always...
I did learn quite few things doing this today, but mostly i learned about
patience... when you have 2 molds and only one key, you can only make one
mold at a time. So, this morning i mixed plaster (5 lbs Pottery#1 plaster
to 3 lbs water, at room temperature) four times. And made 3 plaster bats
and one plate mold, with a rim... The bats (10") all came out fine but
because of the mold soap, there seemed to be uneven surface so i trimmed
the plaster on the wheel, got them nice and smooth. Made a nice groove in
the plate mold for a rim to fit in just nicely, but plaster is a new
material to me and i had no idea... so i made a nice groove and nice
smooth bats and ruined my favourite Kemper trimming tool... oh, well...
maybe i shoulda bought a Groovy tool at NCECA in that shape too...
although the other Groovy tool i did buy is still in good shape, it didn't
work so well on the plaster anyhow, too much chatter no matter the angle i
held it at...
no matter, its all a learning curve thing again... this time plaster.
Still pottery... I fully intend to keep making bats and plate molds til
the bag of plaster is gone cause it doesn't keep so well in damp basement
studios...
If anyone has an extra key for this Pure and Simple system they want to
offload or bats molds, or even other shape hump or slump molds, i'm
interested!
The bats fit perfectly on the key that goes on the wheel although i had to
enlarge the bat pin holes slightly on the key to get them over the bat
pins on the Shimpo... Easy enough to do with a Dremmel bit in the drill...
super easy to get on and off the wheel, a real treat... look forward to
them being dry enough to take for a test run but i have high hopes they'll
be just right... i generally do about most new clay toys...
Thanx again,
Anne Doyle
Saint-Sauveur, QC...
where the snow went down another 6-10 inches today; gotta love it, at this
rate the weeds will have taken over the gardens by the time the snows
gone!
Tom Witman on sun 20 apr 08
I also use #1 pottery plaster for my bats. I found a shallow pie dish
that is perfect for my wheel head. I mounted two pins in a piece of wood
that are the correct distance apart for my bat pins on the wheel. After
pouring the plaster, I locate this wood/pin setup on the pie tin where I
placed marks. Coat everything with mold release or Pam and just keep
making them every hour! I also use Plain and Simple bats the same way.
Plaster bats work VER
Y well to 'suck' the water out of the bottom and release automatically.
John Rodgers on mon 21 apr 08
Anne,
I don't understand why you are using mold soap! Mold soap will seize the
plaster surface an you will get uneven spots or spots that wont aborb
the water from the clay.
Here is how I make a bat for pots or plates using my Pure and Simple Bat
System
Clean the surface of the pan interior thoroughly, buff with a paper
towel. Do the same with the keyway - the face that makes the groves in
the plaster bat.
Pour the plaster, and set the keyway. When the plaster gets hot, remove
the keyway.
Allow the plaster to get hard. but while still hot, turn the pan with
the plaster bat upside down.
Press in the center of the bottom of the pan. The bat should pop right out.
If the bats tend to stick, get a can of Polyease 2300, a silicone mold
release spray, available from Polytek (do a Google search). Lightly
spray the inside of the mold pan, then make the next bat. Spray Polyease
lightly - don't flood the surface. It doesn't interfere with the
absorbing action of the plaster if you don't get carried away with it.
Regards having a spare keyway - be careful. I have discovered that
between production runs in the manufacture of these keyways, there are
dimensional differences. You may find that the bat made with one keyway
will not fit the other keyway which may have been made in another
production run. . I have two right now and that is the case - same
keyway, same company, , but only one fits my bats. It's a big PITA!
Good luck.
John Rodgers
Chelsea, AL
Anne Doyle wrote:
> Many many thanx to all the kind folks who wrote to me on this matter on
> and off-list...,
> the help was greatly appreciated as always...
>
> I did learn quite few things doing this today, but mostly i learned about
> patience... when you have 2 molds and only one key, you can only make one
> mold at a time. So, this morning i mixed plaster (5 lbs Pottery#1 plaster
> to 3 lbs water, at room temperature) four times. And made 3 plaster bats
> and one plate mold, with a rim... The bats (10") all came out fine but
> because of the mold soap, there seemed to be uneven surface so i trimmed
> the plaster on the wheel, got them nice and smooth. Made a nice groove in
> the plate mold for a rim to fit in just nicely, but plaster is a new
> material to me and i had no idea... so i made a nice groove and nice
> smooth bats and ruined my favourite Kemper trimming tool... oh, well...
> maybe i shoulda bought a Groovy tool at NCECA in that shape too...
> although the other Groovy tool i did buy is still in good shape, it didn't
> work so well on the plaster anyhow, too much chatter no matter the angle i
> held it at...
> no matter, its all a learning curve thing again... this time plaster.
> Still pottery... I fully intend to keep making bats and plate molds til
> the bag of plaster is gone cause it doesn't keep so well in damp basement
> studios...
>
> If anyone has an extra key for this Pure and Simple system they want to
> offload or bats molds, or even other shape hump or slump molds, i'm
> interested!
>
> The bats fit perfectly on the key that goes on the wheel although i had to
> enlarge the bat pin holes slightly on the key to get them over the bat
> pins on the Shimpo... Easy enough to do with a Dremmel bit in the drill...
> super easy to get on and off the wheel, a real treat... look forward to
> them being dry enough to take for a test run but i have high hopes they'll
> be just right... i generally do about most new clay toys...
>
> Thanx again,
> Anne Doyle
> Saint-Sauveur, QC...
> where the snow went down another 6-10 inches today; gotta love it, at this
> rate the weeds will have taken over the gardens by the time the snows
> gone!
>
> ______________________________________________________________________________
> Clayart members may send postings to: clayart@lsv.ceramics.org
>
> You may look at the archives for the list, post messages, change your
> subscription settings or unsubscribe/leave the list here: http://www.acers.org/cic/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots2@visi.com
>
>
>
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