Serendipity!

Week 6 to 10

In this blog I will explain the process of casting glass for the large ascension bowl.

You will have read my blogs explaining the maquette and mould making processes however on thing I hadn't explained was, why Pate de Verre?

Pate de Verre is a paste made from mixing glass powder (or frit) with water and gum Arabic.  This paste is very controllable in terms of where you can apply it and how you can sit your colour mixes etc, therefor it is very good for casting specific colour combinations or patterns.  Sound ideal for this project.

The paste can be made more or less fluid and this can impact on the result of the casting.  For example a dry mix will have little fluid to sit between the granules of glass and evaporate while a more wet mix will be the opposite.  These variations can result in granular or smooth finishes, little or lots of shrinkage etc; all of which impact on the final outcome. With lots of experience and experimentation you can master an outcome however the a little experience and experimentation can have unexpected results.  I am no master...

Also, in this project I have chosen to use Bullseye Steel Blue powder.  The steel blue powder is a reactive, meaning it can change colour in the firing depending on temperature and the colours it combines with.  Bullseye almost withdraw the glass when they learned that artist were have erratic results (they pride themselves I having exact products) however the artisans relished these results and the product remains.  The colour change can result in a metallic steel grey finish, as shown in the image below from a fused piece I made last year.

I liked materiality of both the method and colour in that the results would not be predetermined or absolute, in which case this piece was going to create its own fate, its destiny.

I mixed two quantities of paste, one medium amber and the other steel blue, both to a mix ration 7g glass to 1ml water and 1ml gum Arabic; ideally trying to achieve a smooth thick cream consistency capable of sticking to the side of the mixing tub.

I started by applying the amber paste into the thread grooves and allowed them to stand about 5mm proud of the mould.  These raised edges crated the space to apply the blue paste, it also gives a consistent 5mm thickness and assuming about 20-25% shrinkage this should result in a finished thickness of 3-4 mm.

I've been developing ideas for how to finish the rim of the bowl and wanted to lift the idea of ascension.  I've looked at adding lead tips to each of the amber threads so I have applied an elevated flight to each of them, actually took them higher than depicted below.

The Pate de Verre method is brittle given it is just a paste so any demands on it on an upright surface can cause issue when gravity takes hold.  I have used the infill method previously on small pieces; this involves adding an inert powder to support the pasts, in this case ordinary talcum powder.  The talc does not fire and is easily removed after the kiln firing.

Well, I've followed this process methodically and ensured my firing was tested  and established in terms of desired texture and consistency so what can go wrong? The answer, everything!  When I swept back the talcum powder I expected to see some deep and rich ambers and blues shining back at me, not pastel blue and yellow matts.  For some reason the firing had been a failure.  The image below shows the tips and you can clearly see how pale the colours are at the top.  Follow these down and you can see some brighter colours, these are unfired powders.

These side by side comparisons show the cast before and after I sprayed it with clean cold water.  The image on the right has some dark tips that get less dark and more vivid as you look down into the bowl.  All of the bright colours are unforced powders, most of which have been disturbed, if not removed, while tried to remove the talcum powder.

"Well, what are you waiting for?" I hear you ask.  "Just get it back in and fire it again.  Nice suggestion however first of all I have to reapply lots of powder and secondly, did you take note of the cracks along the upper edges?  No? Then take a look at the picture below.  Those upper edge cracks travel all the way down each of the four sides and then across the base where they create a city centre traffic map of cracks.  These cracks introduce opportunities for heat variation in the firing, in fact such cracks would make incredible heat wells that would ultimately affect the firing.  So what do you do?

So let's take stoke.  Re-fire it after some TLC or start again.  I only have 7 days before the Christmas holidays break so not enough time to start from the beginning. We have a cracked mould, but it is still holding together.  We have fired and unfired glass but easy access to re-apply more. The talc may have been too much of an insulator so leave it out.  The cracks could be a big issue for making the glass recede so consider taking the process temperature down 10 degrees. Maybe some TLC is all it needs, who knows?  Fate is really playing around with me here. Let's go for it.

Okay.  Let's take a moment to consider life on Earth.  Its a marvel of the universe.  Of the billions upon billions of particles that exist and the stars and planets they have formed and the location and circumstance of these planets that created the perfect 'Goldilocks Zone' in which our Earth is situated for life to be viable.  Add to that the complex building blocks and some catalyst and there you have it, life on earth.  Pre-ordained or just fate?  Talking of Goldilocks, the porridge was either too hot or too cold and I think my second firing suffered this too...

Yes, this is the same piece and no this is not what I was wanting but yes, I was expecting something to go wrong; but not this.  Its like 6 fickle fingers of fate reaching up for me.  If I were writing a 50's B movie script I'd be yelling, "Run for the hills, its alive!"  But I am not, I'm an artist and I'm making art.  So now what?

It is now the Friday before Christmas, I cannot make a new mould because my forms etc are locked away in college for two weeks, I can't get more glass because the suppliers are now closed for at least one week and postage will add a further week.  On my return to college in two weeks time I will have 7 days to install my submission.  What do you do?  Simple, sit down, take deep breaths and clear your head.  Read the brief.  Read your Personal Learning Plan. Look at your research.  It's fate.  I specifically chose materials and a process that would harness the brief.  I took decisions that pushed them further down that road.  It's not what I was wanting but it does fulfil a brief but I can't present the piece, mould and all.

I recognised aspects in the piece that referred me to my research imagery from archaeological digs and restructured pottery pieces.  I could divest the individual glass pieces from the mould or I could try and secure them together.  I researched the application of clear resin and decided that this was the way to go.

With a two part mixture of 10% catalyst I set about mixing and applying resin liquid.  Because of the bowl shape I could simply pour the liquid in, and due to its 24 hour setting time I could swirl it around until set. A labour intensive routine of tilting the mould, pouring a little resin, set, rotate mould, mix, pour, set and repeat for 7 days.

 The image above gives a view of some of the cracks and voids that resulted from the second firing.  I used some blue tack to fill in the worst of the cracks as I knew the resin is capable of seeping through the smallest of holes and I wanted to minimise both the waste and its results inside the plaster. 

I will now ask you to read the title name of this blog.  Yes, it is serendipity: (noun), the occurrence and development of events by chance in a happy or beneficial way. (Oxford English Dictionary)

I could not believe my eyes, nor the effort my saw required, when I started cutting away the mould.  I started by cleaving off the corners and chamfering away into the underside.  As the plaster started to crumble away at some crack lines it became apparent that something incredible had been taking shape.  It was like looking it a glacier cave.

 

After chopping down that might oak I did a bit of delicate picking away started to reveal just how much resin had manage to seep away and how dramatic its formation with the plaster had been.  I instantly started to conjure up images of calcified archaeology or coral encrusted sea finds.  What had the Norse sea god Aegir served up for me?  In the image below you can see indications of the spiralling plaited threads pushing themselves out from the plaster. 

After a night bathing in a cold bath (the piece, not me) and day of painstakingly (and it was painful) picking and scraping away at the plaster, the full majesty of the piece emerged. After this initial clean off I gave it a further bath and scrub down to remove any further plaster residue and then spent a few hours cleaning the exposed glass with hydrofluoric acid. 

In truth, it was not what I had designed for and not what I expected to execute however it has fulfilled its own destiny to the full.  The results are both repulsing yet compelling.  It is an intriguing piece that not only fulfils the brief of destiny but has grabbed hold of it with both hands (fickle fingers and all) and created itself into something unique.