[Understanding Stucco]

Name: Tenzin, Nina and Karen
Date and Time:

2017.10.16, 12:20pm to 3pm

Location: 260 Chandler
Subject: Making stucco

We read Vasari's definition of stucco and plaster in his book On Technique. Vasari cautions against thinking of stucco as an inferior material. He clarifies that stucco that he is referring to is made using crushed marble. We started our class with Jo Kirby's presentation on stucco and pressed leather. We are still unable to fully differentiate between 'stuc' and 'plastre' as used by the author-practitioner in Fr.640. This is something that we will be figuring out as we read through his recipes more carefully.

In our lab session, we began by revising our protocol for 029r, which is entitled as stucco for molding. Initially, we discussed the importance of looking at the original manuscript (rather than simply the pdf which has OCR). This is to see the change in color or handwriting in margin notes and to get a better sense of whether these additions were revisions after experiments.

This is the protocol based on our class discussion and subsequent experiment.

Materials:

Materials	Amount
Tragacanth gum	6g
Water	24 ml
Rye flour	31 teaspoons
linseed oil*	a little

*Linseed oil is used because it dries (unlike olive oil).

Instruments:

1. Muller
2. Sieve
3. Oil brush
4. Syringe
5. Casting tool

Instructions and observations:

1. Measure the tragacanth gum and add water with syringe. The syringe helps to control the amount of water to use. The recipe says to "soak until, having drunk its water, it is swollen and rendered like jelly." We underestimated the amount of water required. Eventually we used 24 ml of water.

2. Put the tragacanth gum with water paste on a muller. We knead it for a long time. It started to smell like a play dough. We needed the tragacanth gum to be of consistency where it won't stick to itself.

3. Sieve some rye flour and then sprinkle it on the gum and knead it like a bread dough. The consistency to aim for is "it can stretch enough without breaking." This took the longest time. We knead it for more than 15 minutes.

4. Oil the cast with linseed oil, take some of the dough, press it hard and then remove it. We made 3 rounded shape and 6 flat surface ones.

Documentation of our process:

We first combined the tragacanth gum, which was in powder form, with water. It was difficult for us to know when it was done --"jelly" being a rather vague instruction. We erred on the side of caution since we can always add more water but if we add too much, then it becomes an issue.


Once it congealed into a lumpy stand-alone mass, we transferred that to the glass slab to scrape it with a palette knife and mull it, and thusly incorporate the water and gum.


It proved challenging to mull. It was very sticky and gloopy, and did not take well to being 'ground.' This may also have been due to how conservative we were being with the water; since as we added more and it reached a smoother, more jelly-like consistency (jelly like jell-o, not jam or marmalade), it became easier to work with.

Once it was at the texture pictured in the right-hand image (though I sustain that we could have added even more water), we began incorporating rye flour which we had sieved in advance. Sieving proved to be essential, as it removed all the chaff and larger chunks from the flour and left us with a smoother material. This is important given how stucco is used to mold and decorate --the texture could end up being lumpy otherwise.

Trying to blend it with a palette knife proved very difficult --after it gained enough consistency to be manageable, we began to treat it like bread.

It was outrageously goopy and sticky; VERY difficult to manipulate and at this point impossible to knead. We added more sieved rye flour and ultimately ended up with a still goopy but manageable lump of dough and gum, which we could knead.

While it had not reached bread-like consistency (as in, the consistency that bread needs to be when it's ready to be put into the oven) and wasn't as elastic as it should have been (in that, it still broke if we stretched too far as opposed to being more plastic), it wasn't sticky, and Tenzin could knead it without getting her hands coated in sticky flour.


We were running short on time, however, as the gum+water, and flour stages took much longer than we thought --probably because we were being extra meticulous. So despite the texture falling short of what the manuscript author instructed, we determined that because the dough was no longer so unbearably sticky, we could use it for our molds.

Our molds were silicone, and we coated them with linseed oil to make it easier to pull the mold out. We were unsure if we had to leave the dough in the mold for a long period of time or if we could simply stick it in the mold, press down, and pull it out. We tested the latter, quicker method, and it worked perfectly!

We simply had to press down -- the trickier part was ensuring that we could pull the mold up without causing it to become deformed due to unbalanced pressure. The longer strips of stucco were particularly challenging in this aspect. We left them to dry in the vent hood overnight (some flat, some curved) to see how they would hold.

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Name: Tenzin, Nina, Karen
Date and Time:

2017.[October].[17], [06]:[00][pm]

Location: Lab
Subject: Paste glue and stucco results

One day later, we returned to the lab to see how our projects fared. Happily, all of our stucco had survived and held its shape! Our group set about to make paste glue, to glue the stucco onto surfaces. The other group made gesso and rabbit skin glue.

Paste glue was rather easy. It requires hot -not boiling- water, and flour.

We weighed 480 g of water in a beaker, and sieved 208 g of plain white flour. Once the water was hot, we combined the two.



We were too eager in the incorporation of flour. The manscript instructs that it should be done slowly, little by little, but we rushed it. As a result, our paste glue had little lumps of flour which were later impossible to remove. Apart from being aesthetically displeasing, they had little effect on the efficacy final product, though this might also have to do with how our stucco was so small. It might have repercussions if we tried to use it to glue a bigger piece of stucco.




The texture of the glue was... glue-like. Gloopy, sticky, and not too dense, but not watery either. It dripped down from the spoon, but not too easily. It smelled quite pleasant (flour and water, after all). We didn't add salt as a preservative because we didn't need to keep any for later. When it was cooking, we stirred it with a wooden spoon. We tried to whisk the bits of flour out but it didn't work. To apply the glue, we decided to use chopsticks. Brushes were presented as a choice, however, this glue was very gloopy, and we weren't sure how bristle brushes would react. Also, our pieces were quite small, so it seemed inefficient. We tried two methods: application by chopstick, and application by hand.


Both worked fine, so we determined it was up to personal preference. Using our hands was easier, but the chopstick allowed for more tactical application, which was useful for the more complicated pieces. We weren't sure about how much glue to use to ensure it would stick the stucco to the surface. So we yet again erred on the side of caution and loaded it on a lot.



This often resulted in an unseemly excess of glue surrounding the stucco, but it could be trimmed away, or ignored/painted over.

For flat surfaces, we used a rabbit skin glue primed canvas, and a rabbit skin glue primed panel. The canvas was more elastic and had more 'give' when we pressed down, whereas the board was just flat and stiff. We wondered if this would have an impact on whether the stucco would hold.



Gluing onto the canvas (which required a bit more effort).


Gluing onto the board.
Uniformly, when we were gluing things on we pressed down for a few seconds and then let go. Gluing our curved stucco onto a cup made us nervous, so we used a TON of glue.






We were particularly mindful to load on the glue on the edges, since we feared it'd be more likely to 'peel off' there. In an attempt to make the curved stucco hold better, we made a little 'hat' out of another paper cup which would keep it together. We were still worried about the efficacy of the paste glue.




The paste glue dried quickly, so a bit after setting it down we decided to try coating the stucco. We tried a few different techniques:
- rabbit skin glue coating
- gesso coating
- rabbit skin glue and gesso coating
- two coats of gesso
- nothing

We wanted to see which of these took pigment better, and if there was a significant difference between them.

We had to work next to a hotplate where the gesso and the rabbit skin glue were being maintained at a constant temperature. The smell from the glue was very leather-y.


Painting gesso on gesso




Painting gesso on rabbit skin glue. We noticed that using rabbit skin glue and gesso allowed for a greater amount of detail from the mold to show. Also, gesso was more forgiving, since it allowed us to cover up imperfections in our stucco (cracks, etc) without being obvious. However, we had to be careful not to apply too much, or else the detail would be lost. Also, it could easily drip down onto the canvas/surface, which would leave an unsightly white mark.


Our final pieces (with a couple of additions from previous flour stucco batches and some chalk-based stucco). The paste glue held really well. We left them there to dry and we shall see how they turn out once we get a chance to paint them.

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Name: (Also the name of your working partner)
Date and Time:

2016.[Month].[Day], [hh]:[mm][am/pm]

Location:
Subject:

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ASPECTS TO KEEP IN MIND WHEN MAKING FIELD NOTES

• note time
• note (changing) conditions in the room
• note temperature of ingredients to be processed (e.g. cold from fridge, room temperature etc.)
• document materials, equipment, and processes in writing and with photographs
• notes on ingredients and equipment (where did you get them? issues of authenticity)
• note precisely the scales and temperatures you used (please indicate how you interpreted imprecise recipe instruction)
• see also our informal template for recipe reconstructions

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