• Model 8B continued

    I hollowed out the back of the model today which will help let the clay start to firm up a bit, I also did a little minor work on it as well.
    The sculptor has to work around and with the materials and the “mood” of the materials, clay definitely has a “Mood” that depends on the humidity in the room, how moist the clay is, how thick the clay piece is and what is being made with it.
    When the clay is fresh it’s very pliable and soft, it can also be sticky which makes using tools difficult as the clay wants to stick to the tool.
    I usually use just fingertips initially for those reasons, then as the clay starts to lose some of the moisture and become firmer and less sticky, then shaping with tools comes in. It’s a process that the clay won’t allow to be rushed, the degree of this also depends on the exact clay being used.
    I find this red clay seems to be “stickier” and needs more time to dry to firm up than other clays, but the beauty of this red clay is that it has absolutely no tendency to warp or crack, that’s not to say it can’t or won’t but it’s been my experience with it that it’s been extremely stable, so that aspect tends to override the slight negative of stickiness or having to wait longer for it to firm up.

     

    Here’s a newer photo:

     

  • New 8B model progress.

    I cut out a template tool to use to shape the convex holes on the left strip so they are all the same curvature and size, of course they all need cleaning up and refining, but that has to wait for the clay to get firmer as the moisture dries out of it. Right now the clay is still very soft and will be until I hollow out the back.

  • Art Deco D8 model started

    Here’s my clay model just started with the larger scaled design applied to the surface using a ruler, square and compass. The original nickel plated bronze artifact to the left being used to resize the model is from the Women’s House of Detention at 10 Greenwich Ave, NYC which was designed by Sloan and Robertson in 1931.
    The connected courthouse was the scene of the notorious Harry K Thaw murder trial of renowned architect Stanford White in 1906. I rescued several of the individual bronze pieces from the jail when it was being demolished in 1973, I was 13 at the time and even then recognized their importance.


    My clay model when it is completed and dry will need a rubber mold made of it and 3 plaster casts generated from the mold, a 4th cast will be needed to cut that narrow strip off of on the left side to use on the right side as this design will be laid out so it will have 3 repeats and a strip of that border on both sides like photo Nº3 below of my model 8B cast in plaster and given an antique nickel finish.
    The purpose behind making a new and larger sized model now despite having the 8B version for many years which has sold fairly well, is so that I can make this design available in a larger hand-pressed terracotta
    form.
    Were I to make a mold of the 8B the 10% shrinkage with the clay would make the end result unacceptably small and with less impact, it would wind up being almost a tile, so I decided a while back to remake the design to about 23-1/8″ x 15-1/4″ so that it will be the larger size I want, and to compensate for the shrinkage of both this model AND the pressed clay version so it’s final size will wind up being around 18-3/4″ x 12-3/4″, the reason I want that specific size as opposed to say, 19×12 or somesuch is to allow it to be as close as possible to a standard size so that should a client desire to install one in a brick wall it should fit almost perfectly without having to trim bricks or make special arrangements just to get it embedded. Photo Nº2  below shows a rendering of how that works.

  • 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.