Art Deco 8B panel

Now I have the size for the clay model calculated out to allow for the moist to dry shrinkage of the clay model (5%) plus the eventual 10% shrinkage involved with the hand-pressed clay version with it’s drying and kiln firing. Added to these two factors is an additional amount to make the resulting fired clay pressing close to the fired size of the Nortown D5 panel- 18-3/4″ x 12-3/4″

With that calculated out and plotted out on paper I have both my full scale reference print-out and the box-form required to start the model after a little more prep-work.

I’ll be making one section of the repeated design, making the mold of the one-section model, 3 plaster casts will need to be made from that and assembled into the rectangular panel shape, refined and touched up where the seems between them will be, and then another rubber mold is made from that which can cast interior cast-stone and, it will be used to make a rubber positive cast from to make a plaster piece-mold to use to make the hand-pressed clay sculptures.

It sounds complicated but in reality it’s simple, just a lot of intermediate steps. If I were to simply re-use the original sized design it would be much simpler, but then the resulting panel with the shrinkage would be considerably smaller, it would also be an odd size that if someone wanted to insert in a brick wall would demand special trimming and cutting of the bricks to make it fit.

ARt Deco D5 terracotta

Now I have the 3rd fired panel out of the kiln, I had lowered the final temperature 10º to 2050º and the end “hold” time from 10 minutes to 5 minutes. Also, I placed several kiln posts on the floor of the kiln so the panel could set on top of them on end and be raised about 1″ off the kiln floor and still allow the kiln lid to close.

It looks like this solved both issues I had, one was the red color I wanted had started turning towards the more brown spectrum for this clay at the 2060-2079º temperatures, so lowering the temperature to 2050 solved that, the nice rich red brick color I desired is there.

The other issue was in placing the first two panels in the kiln I had set them in place on end directly on the kiln floor, so what happened was the portion of the panel in direct contact with the kiln floor, and extending about 1-1/2″ across the face of the panel the clay did not reach the hotter  2060 and 2079º temperatures the rest of the panel did, so that narrow area turned the red color I wanted while the rest of the panel started to turn towards the brown tint.

This photo shows panel Nr 2 and Nr 3 side by side, the lighting was not ideal and I also had to correct  in photoshop, but the left panel can be seen has an obvious lighter color band on it’s right side, that’s the end that was touching the kiln floor:

The right panel, Nr3 can be seen not only has a brighter red tone than the left half of the left panel, but there is no lighter color band on this one.

Now that I have the red color I want out of this red clay, and I know exactly what temperature it takes to do it, I can repeat the procedures and criteria and keep these pretty consistant.

The thing is, with kilns is that over time the thermocouple that controls the electronic firing sensor on the board tends to lose accuracy with wear and use, “wear” being defined here by X number of firing cycles. I added a digital pyrometer which was used for the first time for this firing, it pretty closely matched the temperature reading of the controller’s display before I went to bed when it was around 1750º. Unfortunately the kiln shut off about 20 minutes before I got out of bed, so I didn’t get to see exactly what temperature the pyrometer reached and how it compared to the controller’s temperature, next time!

I’m very pleased how the hand pressing has gone, none of the three panels cracked, warped or blew out in the kiln under the firing schedule I devised so I know the 36 hours and 57 minutes it took to fire this latest panel is not firing it too quickly. I could probably tweek the schedule a little to shorten the time but the risk there is hitting a critical tipping point and having a pressed piece blow out, also, just because  a slightly shortened schedule might work fine, there could be the first firing with a different design and some slight difference in size or mass, or wall thickness could come into play and it’s just enough it blows out during firing.

So I’m going to keep this shedule where it is, shaving an hour or two off the 37 hour time isn’t worth it and saves very little anyway.

Art Deco 8B panel

I think I’ve all but decided I’m going to “remake” my Art Deco 8B panel with a new slightly larger model and issue it in hand-pressed fired terracotta  too.

The 8B design which I’ve had for years is this one:

8b

It’s 16-1/2″ wide and if I “convert” this to terracotta using the existing design the shrinkage of the clay will make it wind up in my opinion on the “dinky” side around at around 14″ wide, so I’m thinking that if I make a new model around the original size of my Nortown D5 panel it will wind up around 19-3/4″ wide or whatever I come up with so it would also fit the brick cources of a standard brick wall without having to do fancy extra cutting of bricks to make it fit,  if someone wanted to install it in a brick wall.

 

 

 

Butterfly child first cast

I now have the first cast out of the new mold, I gave it the tint base used for the Buff Yellow finish, though I also have this as a non official finish, it’s a pleasing warm color that reminds me of South Western adobe for some reason even though adobe clay and bricks are more of a pale red to pinkish color. Given an application of satin clear sealer it would look very nice.

Here’s another one with a little aging wash added:

It is 22-3/4″ x 19-1/4″ and 5″ deep, weighing about 40#

Winged dog cast

cast

Here’s a concrete cast fresh out of the mold for a client in Nashville that is going on his building.
I need to drill a hole in the bottom for a stainless steel rod, and after it cures a few days wrapped in plastic he will get an acid stain.

The cast weighs 150# so this one has to ship by truck!

The cast was acid stained and then a high quality oil based concrete sealer applied quite heavily as this will be installed in a very exposed location, so it’s a good idea to start it off with the maximum protection. The sealer does darken the color considerably but it will lighten up over time. The sealer and stain gave this a good antique look which will make it look as though it has been up on the building since it was built.

KONICA MINOLTA DIGITAL CAMERA

Metal casting

I decided to order a small amount of Brittania metal from Rotocast metals to do some metal casting, so  here’s five pounds of ingots to stockpile for now:I need to order another 5-10# worth yet. The brittania metal is 98% pure tin, the remaining 2% is comprised of antimony and copper, they were just about $100 for the five ingots, a tad bit less than $20 a pound.

So what am I going to make out of this?

Way back in the early 1990s I experimented with a few dog models, most were cast by a foundry for me in bronze, but one I had decided to try casting in Brittania metal for a set of bookends, this one pictured  below was one of them.

pewter

Making them was a real chore due to the processes I came up with at the time to do it, I had to first make a plaster/sand piece mold from the rubber molds I made to cast wax in for the bronzes, then I had to make a plaster/sand core for the inside to make the cast hollow assemble it all using brass pins to keep the core in position inside, and dry that out in the kitchen stove. Once I melted the metal in a deep fry pan on the gas stove I set the plaster/sand mold in a bucket full of sand and poured the metal into the mold. after it cooled I had to break the plaster/sand mold apart to remove the cast, the core remained inside the cast.

I had made two of them that way. I never made one for myself but I still have the original master rubber molds, so I want to have a bronze of each cast, and I also want to cast at least one in the Brittania metal again.

Somewhere I think I have notes on what I did, I seem to remember it took about 10# of metal, it was a lot cheaper back then too!

Butterfly child panel mold

Now I have the Butterfly child panel sealed with lacquer and release brushed on it’s ready for the Rubber. The model is moist clay in the leather hard stage.

The first detail coat of rubber has been applied to the model.

 

Art Deco D5 terracotta

 

 

 

I took the panel out of the kiln now, still hot enough to need gloves to handle, but it came out very good. I made one small error in the final temperature 2079º I should have set it to 2060º, that 19º difference seems minute in a kiln over 2000º but it makes the difference between the clay turning slightly brown and staying the red color I am aiming for.I had forgotten the higher temperature gave me the browner color a year ago when I fired  another piece to that temperature as a test, and then lowered it to 2060º and the red color remained.

The photo doesn’t show the color all that accurately, so I placed another piece fired at 2060º previously in front of it for comparison. The lion is a redder/orange while the panel is in real life slightly red/brown. This clay will turn a darker chocolate brown at a higher temperature but I that’s not the color I want. So on Thursday morning I’m going to fire the second panel since it’s dry now enough to fire, and fire it at 2060º

The panel as fired measures 19-3/4″ x 12-1/8″ and weighs 29#

Art Deco D5 firing

The panel is still in the kiln since Sunday at noon, it should shut off in about 4 hours. It looks like the panel has survived so far through the critical stages, it could still have a crack or something but we’ll see.

Here’s what 1755º looks like through the peephole on the kiln, now imagine 320º hotter still:

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My Olympic kiln, model 1823HE cone 10 (2350º) is not as large as I wanted, this was $2300 and the next larger size was only a few inches wider and a couple of inches taller inside and it was $3100 which was quite  a jump! For about $3200 they have an oval 42″x 30″ inside that would accomodate larger pieces than this panel and laid flat, but I would also have to  change my breaker box and the wiring to the meter since that kiln needs a dual 70 amp breaker. All my breaker slots are filled, and the main breaker itself is only 100 amp anyway, a 200 amp would be much better.

Art Deco D5 kiln firing

I just put the first hand-pressed clay pressing of the Art Deco panel D5 into the kiln about 5 minutes ago, here it is before closing the lid:

PICT3059smI adjusted the kiln firing schedule  for “User 4″ a little from the previous test firing, I kept the same 5 segment program and holding for 9 hours @ 200º F, but since I want to fire these at a higher temperature- 129º F than I did on the tests I needed to adjust the ramps a bit. Here is what I came up with for this firing on this sculpture, we’ll see how it works:

 

  1. R1: 80º/H to 200º HOLD for 9 hours @ 200º
  2. R2: 60º/H to 1200º
  3. R3: 90º/H to 1700º
  4. R4: 80º/H to 1950º
  5. R5: 60º/H to 2079º

At the end of ramp 5 and reaching 2079º it has a 10 minute hold to let that heat do it’s work and soak in, much like baking a cake the heat has to get all the way into the center otherwise only the outside is “done” and the inside is not yet at the set final temperature.

2079º is what we would consider cone 0  (zero)  if they made one, they make cone 01 and cone 1 so the temperature I found seems to have the best color red in this clay that I like would be between those two cones.

They are properly called “pyrometric cones” and they are little more than a slightly offset pyramidial shaped piece of clay that bends when the heat range it’s made for is reached, it doesn’t measure temperature but it visually shows thta a certain temperature was reached by how far over it bends.

They are made in about 40 heat ranges, from 022  (1087º) coolest, usually used for decals and glazes,  all the way up to at least cone 14 (2523º) which is the hottest, used for porcellains and high fire clay. 2523º is about 600º hotter than it takes to melt  copper, it’s hot enough to melt aluminum, lead, tin, copper, and it’s more than hot enough to melt cast-iron!

Here’s an illustration of cones and how they are often used:cones

Usually used in groups of three, one shows the temperature definitely reached it’s temperature and exceeded it, the center one bends over as shown and that’s just about perfect for showing it reached the desired final temperature without going over it, if the temperature had gone higher than desired (due to  a malfunction or miscalibration  etc) the guard cone would have started to bend too.

These remarkably simple devices were invented in the late 1700s and are extremely accurate, albeit how far they bend over depends on proper level placement in the kiln, and how the operator interprets how far is “far.”

I needed to calculate how many hours it will take the kiln to go through the program and shut off, last time with the slightly different schedule it took  36 hours and 39 minutes, now it looks to be 38-1/2 hours give or take a few minutes. It also takes about  a full day to cool down enough to open the lid and remove either the shattered remains,  or a nicely fired sculpture.

 

 

Winged dog cast

90PICT3053The first cast from the new mold

It took 100# of cast stone and almost 5 gallons of water to fill the mold, after the cast was hollowed out and dried he weighs 90#  The first cast is for myself, I also need to cast one solid, and with the “shims” left intact, as a “master” for future mold making since the original clay model has been damaged.

I cast a concrete cast today for a client in Nashville for his building restoration/renovation, that one is to sit on top of a now closed off chimney. It took 100# of sand and about 40# of Portland cement to cast that one, unfortunately at 140# give or take, plus about 40# for the wood crate, he will exceed the weight limit for FedEx ground and will have to ship by truck.

After he sits in the mold for a couple of days, on Monday I can take him out and see how the cast turned out. I also need to drill a hole up into the base for a stainless steel rod which will be used to help secure the sculpture to the top of the chimney through a hole for the rod to slide into.

I almost finished the model for the “Butterfly child” today, only the face needs to be worked on now to finish it (other than some minor cleanup and the like) I plan to have the model finished if not tomorrow, then this week so I can make the mold before next weekend, probably Thursday I’ll be working on that since I plan to not let the model dry out before molding it, that will also retain the size a bit more but mostly it just needs to get done!

The toes on the original 1906 sculpture number and odd three per paw as my model does too, why three toes? I have a theory that the original artist decided to accentuate the strength of the claws and toes to give it strength and power, that’s supported in part too by the muscles in the forelegs, the massive power of the paws are the first thing that draws the eye on this, to fit four toes on each paw they would have had to have been modelled smaller, and closer together, the impact of that would have been significantly reduced.

I searched for what the design might be called in mythology, closest I could find to this is a winged dog in Armenian mythology called an Aralez. It’s almost certain with the waves of immigrants from Europe, Ukraine, Armenia etc in the 19th century that they would have worked in a terracotta factory such as the one that made these and influenced the designs.
It’s not a griffin or a winged lion, a winged lioness would be doubtfull.

Here’s a drawing of such an Aralez, of course this is an artist interpretation, but following the mythology it’s a large, strong  dog with wings depicted on the battlefield:

 

Aralez

Winged dog cast

I finished the mold for the seated winged dog, it took 3 gallons of Rebound 25 rubber and 125# or so of pottery plaster for the shell. I cast the first plaster cast from it tonight, it took almost two 5 gallon pails to fill, and exactly 100# of the Densite plaster.
After hollowing it out as much as I could while it was setting, the wet out of the mold weight is 100#
So if I figure 19 quarts of water used is about 40#, less what was in the waste from hollowing him out, I’ve noticed about half the weight of water used in plaster casts evaporates, the other half stays chemically bound, so the cast pictured should wind up around 85# which means even crated it can ship FedEx ground.

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Winged dog mold

With the rubber portion completed, now is the time to start on the plaster support shell, herewith is the photo of the first section of the shell hand-formed in place. While this hardens up I need to shovel snow off my driveway unfortunately, but about the time I finish that it will be time to form the next section.

 

Now with the first 2 sections done it’s time to add the rest needed for what will become a 12 piece shell. All the small pieces are required to deal with the multitude of deep undercuts and opposing surface angles. The smaller pieces also make it easier to dismantle and assemble:

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Now with the mold removed from the original clay model it is set up and ready to cast a test interior cast-stone cast from.

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Butterfly child and winged dog mold continued

I was able to spend some time working on this today while making the mold of the seated gargoyle.

The butterfly photo doesn’t show a lot of difference from the one taken yesterday in the previous post, but that’s because the image sie is reduced and the small details are not easy to see. I spent the time working on cleaning up the border, wings, antennae, ribbons and hair, mostly refining, sharpening, straightening and smoothing as needed.

Next session I will be working on the flowers and face, either-or,  or both, there’s a lot of petals that all have to be smoothed, refined and sharpened!

 

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The winged dog mold is in progress, I had to take him off the stand and stand him up on the floor in order to reach into the areas behind the head and wings with the mold rubber. There’s several more applications of it to go yet.

 

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Mulcaster building “butterfly child” model

A new client in Delaware purchased the first public cast of this panel which due to various other projects was not completed in Sept as I had planned!

I really do need to get this model done as the clay does dry out even when kept moist and under plastic wrapping, especially now that the furnace is active and my modelling studio room  warms up fast when it kicks on since the room is small and there’s a good sized register in the wall near the modelling table that blows the hot air out pretty good.

So here we have the current view of the panel, I’ll be working on this this weekend between the seated gargoyle mold and anything else that  might happen along this week!

It won’t take a whole lot to get this finished now really, mostly I need to define and refine the flowers and details, and detail the face.

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