Lesson time limit and pottery time

[Francesco]

According to your experience in a two-hours session it would be possible to model and decorate with engobe some pieces? I am planning a lesson and this is my time limit. The real question is:  could I speed up the drying process to have in so little time the leather hardness required to decorate the works? Can I use a fan?

Thanks!

Edited January 25 by Francesco

[Pres]

When I was teaching HS, in the Summers I ran classes for younger children in Ceramics. I had morning sessions of 2-3 hrs. We would handbuild, and I would have the kids pots in the kiln that afternoon for the bisque firing! No big secret, as I had what was known as a downdraft table (2) in the room. As soon as the students finished their constructions we would put them on the table which would be running. In about 1/2 and hour the pieces would be cheese hard, then 15 minutes later leather hard. This depending on the size of the pieces.  These tables are often used in wood working shops and industry to keep dust and fibres out of the air. If you can find one or build one they are awesome for quick work. Otherwise set up an area with lots of fans and place the pots in it upside down.

 

best,

Pres

[Hulk]

Two hours, maybe?

Fans can speed things up a lot.
Turn the wares frequently and consistently.
Do some trial runs?

We had three hours - lecture and lab - in Wheel I (and Wheel II) at local Junior College ceramic lab, although we could stretch that a bit by showing early.

To speed things along, we could place our just thrown ware on outside tables*, in the wash of a large fan.
From there, turning the ware every ten minutes or so - important for keeping things round.
That seemed to work better than placing wares in the warm box.

In warm dry weather, from clay prep to trimmed ware in three hours, easy.

In damp cool weather, more of a challenge!
I'd tried draping plastic sheeting over wares to keep them until next class.
Ugh, how I loathe plastic sheeting. Then I brought my own bats to class, and covered the wet wares, on the bat, with upside down buckets, which I still do.
Some prefer to load a "damp box" with their wet wares.

During open lab hours, some used electric "heat guns" (looks like hair dryer), which was somewhat frowned upon - several ruined/scorched bats, lots of whiny noise.

I brought my map gas torch a few times; its heat is much more focused than the heat guns' outputs.
One must be careful, however!
 

*Outside, for the fans kick up dust.

Edited January 24 by Hulk
temp and humidity variations; spellin'

[Francesco]

Thanks! I have a dehumidifier and I was thinking of putting the pieces insiede a box and let it slowly suck the humidity out of them. 

20 hours ago, Pres said:

When I was teaching HS, in the Summers I ran classes for younger children in Ceramics. I had morning sessions of 2-3 hrs. We would handbuild, and I would have the kids pots in the kiln that afternoon for the bisque firing! No big secret, as I had what was known as a downdraft table (2) in the room. As soon as the students finished their constructions we would put them on the table which would be running. In about 1/2 and hour the pieces would be cheese hard, then 15 minutes later leather hard. This depending on the size of the pieces.  These tables are often used in wood working shops and industry to keep dust and fibres out of the air. If you can find one or build one they are awesome for quick work. Otherwise set up an area with lots of fans and place the pots in it upside down.

 

best,

Pres

I love your idea, Pres! But I dont have that kind of table, I think doing some experiment with a fan could help me.

 

Thanks Hulk, yes, I mean two hours. I will try what you suggested!

 

[Bill Kielb]

On 1/24/2024 at 10:27 AM, Francesco said:

The real question is:  could I speed up the drying process to have in so little time the leather hardness required to decorate the works? Can I use a fan?

Fans and clay studios - bad mix. Two very popular ways to get this done, place the pot on an unused wheel rotating very slowly and a fan blows on the pot while it’s revolving. Old habits die hard - folks would set their ware on top of an operating kiln (usually along the edge not where it could be screeming hot). Oh, and third I have chattered things nearly right after throwing (10 min.) by drying with a heat gun while still rotating slowly on the wheel until stiff enough to chatter. Dry evenly inside and out, don’t overheat.

None of these are great for the ware, but as a way to move the demonstration along ….. the bowl below was thrown, dried and chattered nearly all at once. Definitely dried out enough to demonstrate chattering.

Edited January 25 by Bill Kielb

[Denice]

It really depends on the humidity level where you live.   I live in Kansas very hot, windy and can be humid or dry.   I took a summer throwing class,  we would take a freshly thrown piece outside  and place it in the sun.   The wind was always blowing,  we would take breaks and turn the pot  until  it was stiff enough to cut off the bat.   Trim the pot and start the drying with bottom up,  by the time class was over they were almost totally dry.   A humid day took much longer.    Denice

[Francesco]

Great answers, really helpful. Thanks a lot.

[Roberta12]

I took a workshop where they had a "drying room"  All of our pieces (we were using porcelain) went into this room which was outside of the studios.  It was sort of cobbled together plywood walls with lots of shelves and fans and heaters.  The interns educated us about the importance of air flow surrounding the drying pots.  We did not have one piece that broke, cracked or anything.  I have used that here at my house.  Admittedly I live in a very dry climate, but I put all the drying pots in the spare bedroom, turn on the fan, if necessary add a heater to the mix and close the door.  If you could find a way to do that, close off the drying pots so the fans aren't blowing clay dust everywhere.   However, I only do that if I am crunched for time.  No sense in using extra resources.

Roberta

[Callie Beller Diesel]

The studio I work at does something similar, and we wind up using hair dryers to set up the surface of the piece enough to take a coat of underglaze that isn’t streaky.