Up to what temp can I vent?

[Magnolia Mud Research]

Have a look at this John Mason sculpture, 

images are at: 

 

and:
http://www.artnet.com/magazineus/features/drohojowska-philp/ceramics-in-los-angeles-3-21-12_detail.asp?picnum=7 and 

pictured in the second edition of Daniel Rhodes book "Clay and Glazes for the Potter" has the following caption by Rhodes: "John Mason.  Cross.  This massive sculpture,  made of solid clay,  is 5 1/2 ft.  high.   A mustard-colored glaze partially covers the surface" 

John Mason
American, born 1927
Cross Form, 1962/63
Stoneware with glaze
161.3 x 132 x 91.4 cm (63 1/2 x 52 x 63 in.)

Gift of the Ford Foundation, 1964.71
http://www.artic.edu/aic/collections/artwork/20428?search_no=1&index=0 

John obviously knew how to fire thick pieces without blowing them up. 

Also remember house bricks are thicker than one half inch! 

Large sculpture pieces are usually made with a clay body designed for sculpture and have a firing schedule designed specifically for sculpture.  The half inch limit is seems to have developed for table ware and household storage containers.   

LT

 

[pizzuti_]

5 minutes ago, Babs said:

Not strange at all but heed the ambient humidity,  where your piece is placed in your kiln , slow drying of piece. If the surface dries quickly or unevenly it can seal the clay to the point that moisture cannot escape from the interio thus the skewering from base up into the interior.

This becomes more severe in the firing.

Drying off the base , rotate surfaces which are exposed to sure during drying. Wrap in plastic and dry SLOWLY etc etc.

Fire on could of clay or a layer of fine grog to allow heavy sculpture to move as it shrinks.

All the best 

Good tips, thanks.  I think my biggest problem here might be the humidity and damp location. 

[pizzuti_]

1 minute ago, Magnolia Mud Research said:

Have a look at this John Mason sculpture, 

images are at: 

 

and:
http://www.artnet.com/magazineus/features/drohojowska-philp/ceramics-in-los-angeles-3-21-12_detail.asp?picnum=7 and 

pictured in the second edition of Daniel Rhodes book "Clay and Glazes for the Potter" has the following caption by Rhodes: "John Mason.  Cross.  This massive sculpture,  made of solid clay,  is 5 1/2 ft.  high.   A mustard-colored glaze partially covers the surface" 

John Mason
American, born 1927
Cross Form, 1962/63
Stoneware with glaze
161.3 x 132 x 91.4 cm (63 1/2 x 52 x 63 in.)

Gift of the Ford Foundation, 1964.71
http://www.artic.edu/aic/collections/artwork/20428?search_no=1&index=0 

John obviously knew how to fire thick pieces without blowing them up. 

Also remember house bricks are thicker than one half inch! 

Large sculpture pieces are usually made with a clay body designed for sculpture and have a firing schedule designed specifically for sculpture.  The half inch limit is seems to have developed for table ware and household storage containers.   

LT

 

Wow, I love that. I imagine him firing it in a fire pit. I'll have to research it and see if I can find out how he did it.  I have a friend that sculpted a huge head, like 5' tall, he dug a massive fire pit to fire it.

Yeah, I forgot about bricks!  I think you're right, were talking apples and oranges here, well not that different....but pottery and sculpture are different.

[Babs]

Not apples and oranges at all... knowledge and consideration given to choice of clay body most suited to your project, , and knowledge of construction, drying and firing  such a clay body along with  size of sculpture.......

Just saying...

Many sculptures are hollowed out or built around an armature which burns out in the firing process. Weight of end piece also a consideration depending on script as it were.

[Tyler Miller]

It should be said, gas is a much more forgiving firing method than electric.  Wood too. Burning hydrocarbons produces water as a byproduct.  Very different than electric’s 0% humidity. 

I’m of the hollow it out camp, but mainly because I like light pieces aesthetically.  I’ve had a few thick pieces dunt, but I usually cool stuff quick.

Peter Voulkos’ stacks look pretty thick?

I dunno—it’s all about what you want and what you can make work (and what you can feel good about selling) as an individual artist.  

[yappystudent]

Interesting, well if it works it works I guess. I'd never want to swim upstream against that much tradition but I'm curious to see someone else do it and have it turn out. 

[Chilly]

The biggest issue with drying of solid pieces is the surface.  It dries faster than the inside, and shrinks and forms a nice tight skin.  The inside moisture now has a harder job to evaporate through that skin.  The thicker the piece the longer and longer it takes.  If it takes a week for a 10mm thick piece to dry, it does not follow that it will take two weeks for a 20mm piece.  More like three or four weeks.

If you really hate hollowing or want solid pieces you could make a mould from the original instead of firing it and cast it in a different medium altogether.  Metal or plaster or slip cast it and then you could leave it thick but uniform and hollow which would aid it's drying.

[Sputty]

.
 

[neilestrick]

You can fire pieces of just about any thickness, but you have to fire slowly. My reference to 1/2 inch thick is for a typical firing schedule. If you want to work 2" thick, you need to be prepared to  extend your firing time to several days, including a controlled cooling.

Many wood firings, especially  those that Peter Voulkos' pieces were fired in, are very slow firings. A few days to get up to temperature, and several days to cool

[Benzine]

When I assign my sculpture project, I allow the students, to build it, using any method they'd like.  It is the final project, and at that point, we've been through, pinching, coil building, slab building/ slumping.  I do allow them to hand model the clay, and hollow it out, as well.   However, when they ask my opinion, I'll tell them to go with slabs or coils, depending on the form they are looking to achieve.  For curvy, more organic objects, I highly recommend coils.  For things that are more geometric, I recommend slabs.  Regardless of the building method, they know the rule that I've hammered home since the first week of class.  I won't fire anything that is an inch thick or over.  The thickest slats I have for making slabs are 1/2" and the extruder makes coils that are about the same.

Using either slabs or coils have the benefit of knowing exactly how thick, every spot of the sculpture is.  It is very difficult to hollow a sculpture out, to a consistent thickness.

The issue isn't just with steam related explosions either.  There can also be issues, when the chemical water is "burned" off, not to mention all the changes to structure that happen at different points of the heating and cooling process.  There is a lot of stress going on there, with thick pieces.

Finally, you have the problem of thick and thin(ner) spots drying, expanding/ contracting at different rates.  If you have a thicker spot of your sculpture, next to a spot that is thinner, they will pull away from each other, due to how quickly the expand and contract.  This will lead to some bad cracking, and other structural flaws.   That actually reminds me of several years ago, the year my District hosted our Conference Art Show.  One of the judges I got, was a ceramicist.  We got to the Ceramic Sculpture category.  There were a couple from one of the other schools, that I thought were really nice.  They were large, detailed, and had great subject matter.  They didn't place very well, if at all.  The reason is, the judge looked at how they were made.  They were built solid, and hollowed out.  They survived the firings, but with some cracking.  However, they were insanely heavy for something their size.  The judge did not like that at all.  

 

Your sculptures look great, and I know myself and others here, just want them to turn out the best that they can, hence the advice.  

[Marcia Selsor]

On 7/12/2018 at 12:09 PM, pizzuti_ said:

Well they looked dry and I always fire slow. Any idea when I can stop venting?  I'm just being extra careful now.

if they are cool to your cheek they are too wet. 

 

[Marcia Selsor]

On 7/13/2018 at 4:37 PM, Magnolia Mud Research said:

Have a look at this John Mason sculpture, 

images are at: 

 

and:
http://www.artnet.com/magazineus/features/drohojowska-philp/ceramics-in-los-angeles-3-21-12_detail.asp?picnum=7 and 

pictured in the second edition of Daniel Rhodes book "Clay and Glazes for the Potter" has the following caption by Rhodes: "John Mason.  Cross.  This massive sculpture,  made of solid clay,  is 5 1/2 ft.  high.   A mustard-colored glaze partially covers the surface" 

John Mason
American, born 1927
Cross Form, 1962/63
Stoneware with glaze
161.3 x 132 x 91.4 cm (63 1/2 x 52 x 63 in.)

Gift of the Ford Foundation, 1964.71
http://www.artic.edu/aic/collections/artwork/20428?search_no=1&index=0 

John obviously knew how to fire thick pieces without blowing them up. 

Also remember house bricks are thicker than one half inch! 

Large sculpture pieces are usually made with a clay body designed for sculpture and have a firing schedule designed specifically for sculpture.  The half inch limit is seems to have developed for table ware and household storage containers.   

LT

 

he was one of the 6 ceramicists exhibited at the Whitney as a ground breaking event for ceramic art in 1980.  Gilhooley, Mason, Voulkos, Price, Arneson and Shaw.

I saw a show of the 6 of them at the San Jose NCECA around that time.Mason's work was powerful. They all were. I digress  https://archive.org/stream/ceramicsc00fole/ceramicsc00fole_djvu.txt

 

[Benzine]

28 minutes ago, Marcia Selsor said:

if they are cool to your cheek they are too wet. 

 

I've always found that difficult to gauge personally. 

It's not that they don't feel cool, it's just that they almost always do to me.  

 

[Pres]

I fired a lot of student work, much would be considered sculptural and was thicker. Often they would be the last to be fired, before firing would set on the kiln double thickness kiln lid until the next firing, fired on the lowest level of the kiln, fired very slowly-two days to ^06, and often loaded into the kiln on shelves with grog, or short small extruded coils under them. These usually survived, 

I also recall using pealite in a ceramics workshop for fast firing. This insulation material was added to the wet clay and thrown or carved and then fired after sun drying for a few hours. ^06 went overnight. Some of the pieces were thicker (sculpture) and had to be fired longer, but still pretty quick. In working with something like this I would imagine the surface quality would be of concern, but it is possible to use that to advantage.

 

best,

Pres 

[Benzine]

Pres,

 

In some instances, I will also put work, on the kiln lid, but only if I am sure, that it is mostly dry to begin with.   The project shelf, for work that is ready to be fired, either time, is directly across from the kiln.  That way, any greenware, gets a little extra heat and dry air before they are fired.

I will also regularly set projects on our air vents.  During the Fall and  Spring, that does a bit to help, but our building has AC, so the air is quite cool.  During the Winter, with the heat going, a project can be dried in no time flat.  In fact, some students have forgotten things, they were trying to partially dry, on the vent and come back to find them very, very bone dry.

Between all this, and my very slow bisque program, explosions *Usually* are not an issue.  

[Pres]

Ben,

I had downdraft table in my room. These were bought to collect dust using a filer system. They were really loud even with my poor hearing in the last years. However, when teaching Summer classes (one week workshop) I would put pieces on the downdraft tables after class at 12, and have them loaded in the kiln firing by 3. What a tool for fast workshops. No heat, just constant air moving around and under the pot caused them to dry evenly and completely.

 

best,

Pres

[Benzine]

Pres,

I remember you mentioning that table before.  It actually made me want to make my own, with a wood frame, some peg board and box fan.  I haven't done it yet, but definitely might!  

You know how it goes, tons of ideas, for ways to improve the classroom, but only so much time.

[Pres]

The really large fan was mounted parallel to the floor. I would imagine you should start with an attic fan.

 

best,

Pres

[Rae Reich]

On 7/13/2018 at 3:43 PM, pizzuti_ said:

Wow, I love that. I imagine him firing it in a fire pit. I'll have to research it and see if I can find out how he did it.  I have a friend that sculpted a huge head, like 5' tall, he dug a massive fire pit to fire it.

Yeah, I forgot about bricks!  I think you're right, were talking apples and oranges here, well not that different....but pottery and sculpture are different.

Mason fired in a very large car kiln. It has a platform (front door attached) that rolls out to load, and rolls back into the kiln shell to fire. It was all the rage for some colleges and community colleges to have them in the '70's. Not very practical for loads of student work since they need so many pots to be full. We never saw any finished student pieces until Christmas!

i think @Mark C. has a somewhat smaller version for his high production. 

@pizzuti_, your work is much smaller than I had originally envisioned, (unless you meant feet, not inches!!) so your drying time seems to be working for you, except for the beads. You can put pieces that you have to fire soon but are maybe not completely dry into an oven - not microwave- on low, or pilot for gas, overnight to be more sure.

[liambesaw]

On 7/19/2018 at 6:11 AM, Pres said:

Ben,

I had downdraft table in my room. These were bought to collect dust using a filer system. They were really loud even with my poor hearing in the last years. However, when teaching Summer classes (one week workshop) I would put pieces on the downdraft tables after class at 12, and have them loaded in the kiln firing by 3. What a tool for fast workshops. No heat, just constant air moving around and under the pot caused them to dry evenly and completely.

 

best,

Pres

Laminar flow hood?

I've built one and they're a pain to get right.  A blower fan, a 'plenum' area where air pressure can become static, and then it flows down in a perfect column.  But for drying ceramics I bet a box fan mounted to the top of some wire shelving and pointed down at the ware would work great haha

[Pres]

So the table we had was wooden, about 6' square, a metal frame base with 4 filters filling the side walls. The fan was pointed downward under a top that was basically masonite like peg board with larger holes around the outside 1' around the edges with peg board size hole in the center. You would swear when it started up that it was going to take off as it sounded like jet spinning up.  The fan had a large round frame that reminded me of an attic fan. I have not found the specific table, but there are several if you google downdraft table. There is also a plan to build a small one:

https://fixthisbuildthat.com/diy-downdraft-sanding-table-box/

I would think someone with a little tool skills could build it.

 

best,

Pres