Heat Work and Degree of Slump

 Searching for a Relationship in Heat Work in the Slumping Range. 

Now I know why so little research is published that indicates a lack of any positive results.  It is disheartening.  There is no pointer to other methods or relationships.  It is difficult to pick yourself up and try something different.

Yes, this means that my testing for a relationship between time and temperature and degree of deformation was unsuccessful.  With the means at my disposal the relationship between viscosity, heat work (time and temperature) and the degree of deformation is either too complex for my equipment, methods, or concepts.  I found no formulaic relationship between time and heat to get the same amount of deformation, due (I believe) to the factor of viscosity.  And I have no way to measure viscosity.

Some things did become apparent (many of them already known)

Holding time constant and increasing the temperature results in greater deformation.  Nothing new in that.  Holding the temperature constant and increasing the time results in more deformation.  No general relationship could be determined.  But at 650C changing the time from 15 minutes to 45 minutes resulted in an almost linear increase in the proportion of deformation, but a decreasing proportion from 35 to 55 minutes, although generally regular from 15 to 35 minutes.

There is a mild relationship in the amount of deformation between increasing time between 640C and 670C, but this breaks down at 630C and below, where increasing time does not “counteract” the lower temperature.  My speculation is that the viscosity is too high below 630C to maintain that (very mild) relationship. 

Top blue line is the temperature times 10; orange line is the temperature; the others are the thicknesses.

There is a relationship at a given temperature with the proportion of deformation within each thickness.

 

This graph shows increasing time at 650C.  The 12mm thick test piece has a relatively regular change throughout the time range of 15 minutes to 45 minutes.   The 6mm and 9mm pieces show similar proportional changes up to 35-minute soaks, but then drop as the time continues to increase.  This is weird and requires further investigation to see if it is an experimental bias or something else.

At the best, this writing up of my failures, has led me to renewing my tests of deformation by controlling for time and for temperature separately.  The first of the new tests is in the kiln now.

Urban Distopia

Percolating away in my brain for some years has been a difficulty in finding a way of representing the destruction and violence at national levels.  At each stage something prevented me from continuing with any of the ideas.

Now after a visit to a conference, where there was some discussion about both techniques and expression, a new vein of thought and its possible expression began.  This is the first iteration of that thread of thought.  

Urban distopia is about the things that go wrong even when we - either as individuals or as a society - try to do the right things.  This first expression of the idea is based on the destruction being felt throughout the middle east.

Destruction (Urban Distopia 1)

The mirror is an attempt to reflect our responsibility for these things.  We are not just observers.  When we look at the destruction, we are reflected in it.  

Placed on a plinth at approximately eye level, the viewer is reflected amongst the destruction.

Glass Bra

Another interesting project has come my way.   A burlesque artist approached me with a request for a glass bra.  She is going for an Arts Deco theme and took inspiration from the 1917 film Cleopatra staring Theda Bara

As you can see this was a very dramatic costume as well as having "theatrical" gestures.  The artist also found one part of the bra for sale on ebay.

This is a beaten copper or brass piece with a "jewel" set into the snake's head.  (I wonder how the two parts got separated?)

However the artist felt that a glass version would be more dramatic.  So we began experimenting to get the shapes right for her.  A cast was taken to ensure the pieces would be comfortable.  This was used to make a mould for the glass to drape over.

Fused shapes on mould

First trial

The first trial showed some design faults, requiring the snake's head to be holding the tail, so that it did not slip.  The head needed to be a bit larger, and the linkage system between the two cups improved.  The chain needed to be silver coloured and "flatter".

There were other pieces to be prepared for the costume too.  You will need to wait for the performance for the whole costume to be revealed.  I will add it here when I have the images.

And here is the whole costume:

Large Scale Enameling

Another student from the Glasgow School of Art came to see if I could help with the enamelling of large copper pipe for her MFA show.  Mimi shows the wide appeal of the GSA as she is French Canadian - although I thought her a French national for several weeks.

This required a lot of experimentation. The electric kilns oxidised very badly if placed in a cold kiln and taken up to temperature.  The glass kiln worked much better with this kind of heating.  However, it is known that copper enamelling is done by placing the copper in the annealing oven when it is hot for a few minutes.

Among the first experiments were getting the enamel powder around the whole of the pipe.  Normally, enamelling is done on a flat surface, and the powder needs to only sit on top of the copper.  With a three dimensional surface, a flux needed to be applied, which would be viscous enough to stay on the pipe without dripping and also hold the powdered enamels.

So be began experimenting with temperatures required.  It became apparent that there was so much heat lost in opening a large kiln that we needed to heat the kiln 50 to 100 degrees above the 800 target temperature. This depended on the size of the kiln, but not in the way expected.  The smaller kiln lost more heat and required more time to recover than the large kiln.  So the large kiln needed only about 50C over the target temperature, and it recovered to 800C within 5 minutes which was enough to heat the pipe and fuse the enamel to it.

This heating process was very dramatic as you can see from the photos of the process:

Getting ready to open the kiln

Placing the pipe in the kiln

Even though I was standing 4 metres away, I could feel the heat almost instantly.  But denim jackets put on backwards, gloves, heat reflecting sleeves and face guards were sufficient for the brief exposure to the intense heat.  

Then once the kiln climbed back to temperature, they had to reach in and take the cured pipe out without letting it touch the floor of the kiln, or burning the surface on which the pipes were cooled.

One of the larger diameter (50mm) pipes after initial enamelling of the base colour.

The enamelled pipes were of course only part of Mimi's  MFA exhibition.   All the MFA students exhibit in an old glue factory!  The most interesting part of the building for me was the tanks which were still in the building.   Other wise it was a series of rooms and large (probably) drying areas.

One of the pieces at the entrance to a room

Another free standing piece 

One of the longer, but smaller diameter pieces fixed to the wall

The whole MFA show was varied - from a number of video pieces and installations, installation pieces some of which had a craft appearance, photography, but surprisingly (to me, but not others who follow the conceptual art movement) very little painting.

It is good to report that Mimi received her degree and is now off to mount an exhibition in Germany, before getting ready for others in the UK.