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plaster thread on reclaiming plaster

updated tue 22 jan 08

 

Jonathan Kaplan on sun 20 jan 08


So if we have as posted, $50 bucks to ship a $10 bag of plaster.........

Let's say that you value your time at $15 an hour, hypothetically
here......

1.You take your old plaster molds, whatever you have in the studio,
either break them apart or otherwise crush them, or just load them
into your kiln.....there is
maybe 1 hour of time $15.00

2.You fire your kiln to maybe around 220 degrees F to calcine the
plaster, but how do you know the correct temperature to start or stop
the beta/alpha or alpha/beta reaction? Are you sure that you know
this will work?
So you then have maybe $5.00 in electricity, more if you are on a
demand billing system and heavens, exceed that allocated 25KW of peak
demand in whatever time frame and you then get bumped into the higher
rate level
So $5.00 electricity and lets say maybe $2.50 in time to load and
unload those chunks of plaster

3. Then you need to crush and grind that resulting calcine mess and
do it right. You don't have crushing and grinding equipment, right?
SO you do it by hand and it takes another hour, add $15.00, maybe
more to get everything sized right, and then you screen it to make
sure.........

4. Now you are ready to mix and pour whatever you have re-constituted
by hand in your studio. You form it up, do what needs to be done, and
find out that it doesn't work.
So there is another hour of time, $15 here, not to mention your
wasted efforts so far. So to recap the costs here

$15 to crush your old plaster
7.50 firing and some ancillary labor
15.00 crush and grind
15.00 to remix, form and pour

Total is according to my math $52.50. Why would you not buy the bag
of plaster and have it shipped. Oh I do know, you don't value your
time? You have nothing better to do than not make pots?

Potter, puhleezee!!!!

And it certainly won't work. Here is another example of the
"cheap"potter example, or model of why business and potters just
don't work, or better put, why potters with this mindset just don't
get it and waste their precious time pursuing pointless activities
that lead even more pointless results.

I'm sorry to break this bubble but it never ceases to amaze me that
this "cheap in the disguise of being frugal mentality" is still so
pervasive in our field. While I am all for finding ways to really
save money in the studio, this certainly is not one of them, IMHO!

Respectfully,

Jonathan



Jonathan Kaplan
Ceramic Artist/Ceramic Designer
Master Mold and Model-Maker
Plinth Gallery/Ceramic Design
3520 Brighton Blvd
Denver, CO 80216

www.plinthgallery.com

303 909-5488 cell
303 295-0717 office

John Rodgers on sun 20 jan 08


Jonathon,

You are dead on target here.

I have messed with plaster for more years than I want to count.

Reclaim plaster? Spare me and my body .......... as the Lil' Boy sez,
"There ain't no way!!"

Plaster requires an industrial process to get it right, and there is no
way to get it right by hand in a potter's shop. Just won't happen. And
on top of that, the industrial process not only gets it right, it
produces in such mass quantities that the price is reasonable. How would
anyone like to buy a handmade car? There are a few in the world who can
afford and do purchase such, but for the rest of us, we could never
afford it. The small production runs would make the price too high.
But, we can afford a modern, mass production vehicle, and that is what
industrialization and mass production does - makes the product available
at a reasonable price. There is no way one can compete with industry on
industrial materials such as plaster. Why do most of us buy bagged clay
- either pugged or dried? Because there is so much work involved in
producing our own, that the time spent is not worth it. Better to do
something else in the time saved by just buying bagged clay. Big
machinery allows for more work in a shorter period of time, and so big
volumes of clay can be made up. Far more that an individual can dig, and
process on his own. It's not worth it.

I do think however, that "rolling one's own" so to speak is a good
thing, to the extent that it gives one an appreciation for what goes
into the process, and an appreciation of those old time potters who have
gone before, doing it all by hand. They are the ones who laid the
foundation for todays potters.

Regards,

John Rodgers
Chelsea, AL

Jonathan Kaplan wrote:
> So if we have as posted, $50 bucks to ship a $10 bag of plaster.........
>
> Let's say that you value your time at $15 an hour, hypothetically
> here......
>
> 1.You take your old plaster molds, whatever you have in the studio,
> either break them apart or otherwise crush them, or just load them
> into your kiln.....there is
> maybe 1 hour of time $15.00
>
> 2.You fire your kiln to maybe around 220 degrees F to calcine the
> plaster, but how do you know the correct temperature to start or stop
> the beta/alpha or alpha/beta reaction? Are you sure that you know
> this will work?
> So you then have maybe $5.00 in electricity, more if you are on a
> demand billing system and heavens, exceed that allocated 25KW of peak
> demand in whatever time frame and you then get bumped into the higher
> rate level
> So $5.00 electricity and lets say maybe $2.50 in time to load and
> unload those chunks of plaster
>
> 3. Then you need to crush and grind that resulting calcine mess and
> do it right. You don't have crushing and grinding equipment, right?
> SO you do it by hand and it takes another hour, add $15.00, maybe
> more to get everything sized right, and then you screen it to make
> sure.........
>
> 4. Now you are ready to mix and pour whatever you have re-constituted
> by hand in your studio. You form it up, do what needs to be done, and
> find out that it doesn't work.
> So there is another hour of time, $15 here, not to mention your
> wasted efforts so far. So to recap the costs here
>
> $15 to crush your old plaster
> 7.50 firing and some ancillary labor
> 15.00 crush and grind
> 15.00 to remix, form and pour
>
> Total is according to my math $52.50. Why would you not buy the bag
> of plaster and have it shipped. Oh I do know, you don't value your
> time? You have nothing better to do than not make pots?
>
> Potter, puhleezee!!!!
>
> And it certainly won't work. Here is another example of the
> "cheap"potter example, or model of why business and potters just
> don't work, or better put, why potters with this mindset just don't
> get it and waste their precious time pursuing pointless activities
> that lead even more pointless results.
>
> I'm sorry to break this bubble but it never ceases to amaze me that
> this "cheap in the disguise of being frugal mentality" is still so
> pervasive in our field. While I am all for finding ways to really
> save money in the studio, this certainly is not one of them, IMHO!
>
> Respectfully,
>
> Jonathan
>
>
>
> Jonathan Kaplan
> Ceramic Artist/Ceramic Designer
> Master Mold and Model-Maker
> Plinth Gallery/Ceramic Design
> 3520 Brighton Blvd
> Denver, CO 80216
>
> www.plinthgallery.com
>
> 303 909-5488 cell
> 303 295-0717 office
>
> ______________________________________________________________________________
>
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>
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>
>

Ingeborg Foco on sun 20 jan 08


Jonathan,

Your point is well taken but I think the writer was thinking of calcining
unused plaster which had absorbed some moisture from sitting around, not
breaking up old plaster molds and recycling them. (maybe I missed part of
this discussion)

I run into this problem all of the time, little rice size hard particles in
plaster that isn't all that old. Living in Colorado, you are fortunate in
that you probably never have a moisture problem with bags of unused
plaster. In SW Florida, the humidity can be oppressive and it seems to
gravitate into the plaster bucket no matter how well you have sealed it.
Example: today it was 53o F and the humidity was 94% in the morning.

After this discussion, I am going to try to calcine my lumpy plaster if I
can figutre out the details. I only use the plaster for hump/slump molds.
Nothing really so high tech about that. If you don't use the lumpy plaster,
you have to feed it to the garbage guy in small weekly amounts nicely
packaged and that takes time too :)

I live in the middle of nowhere and shipping is a major expense. Whenever I
order a ton of clay I try to order all of the other large items to get a
bang for my shipping buck. Unfortunately, I always seem to forget something
and UPS charges are outrageous compared to the semi that brings the pallet
of clay which is getting more and more costly as well.

Anyhow, it is just another viewpoint from someone who doesn't live close to
a metropolitan area where supplies are readily available. You are one lucky
guy!

Ingeborg

www.thepottersworkshop.com



On Jan 20, 2008 12:47 PM, Jonathan Kaplan
wrote:

> So if we have as posted, $50 bucks to ship a $10 bag of plaster.........
>
> 1.You take your old plaster molds, whatever you have in the studio,
> either break them apart or otherwise crush them, or just load them
> into your kiln.....there is
> maybe 1 hour of time $15.00
>
> 2.You fire your kiln to maybe around 220 degrees F to calcine the
> plaster, but how do you know the correct temperature to start or stop
> the beta/alpha or alpha/beta reaction? Are you sure that you know
> this will work?
> So you then have maybe $5.00 in electricity, more if you are on a
> demand billing system and heavens, exceed that allocated 25KW of peak
> demand in whatever time frame and you then get bumped into the higher
> rate level
> So $5.00 electricity and lets say maybe $2.50 in time to load and
> unload those chunks of plaster
>
> 3. Then you need to crush and grind that resulting calcine mess and
> do it right. You don't have crushing and grinding equipment, right?
> SO you do it by hand and it takes another hour, add $15.00, maybe
> more to get everything sized right, and then you screen it to make
> sure.........
>
> 4. Now you are ready to mix and pour whatever you have re-constituted
> by hand in your studio. You form it up, do what needs to be done, and
> find out that it doesn't work.
> So there is another hour of time, $15 here, not to mention your
> wasted efforts so far. So to recap the costs here
>
> $15 to crush your old plaster
> 7.50 firing and some ancillary labor
> 15.00 crush and grind
> 15.00 to remix, form and pour
>
> Total is according to my math $52.50. Why would you not buy the bag
> of plaster and have it shipped. Oh I do know, you don't value your
> time? You have nothing better to do than not make pots?
>
>
>
>
>

Bruce Girrell on mon 21 jan 08


Ingeborg Foco wrote:

> I think the writer was thinking of calcining
> unused plaster which had absorbed some moisture from sitting around, not
> breaking up old plaster molds and recycling them.

That is indeed correct. A bag of plaster can sit for some time around here
and absorb moisture that affects its setting properties. With the quantities
that I use (small) it makes good sense to me to calcine the plaster to
restore its properties.

I would never think of trying to save money by breaking up and calcining old
molds. Good grief! I can't imagine what contaminants the molds may have
picked up during their working life.

I also qualified my position at the end saying "For durable molds like you
need Jonathan, there is no question that calcining is very poor economy." If
I made my living making molds, there is no way that I would tolerate using
aged plaster. I'm often one of the first to gripe about potters who try to
save a penny by salvaging a glaze mix gone wrong. Just throw the stuff out!
It's very poor economy. You're risking your primary product.

But when all I want to do is make a hump mold and all I have is an old bag
of plaster with some lumps in it, you'd better believe that I'm going to
calcine.

Bruce Girrell