UCLA/Getty Conservation Program

A graduate conservation training program focusing on the conservation of archaeological and ethnographic materials


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Tight, Aligned Joins Does Not a Sprung Vessel Make

In our first quarter class, CAEM 260: Structure, Properties, and Deterioration of Ceramic, Glass and Glazes, we were assigned a ceramic object on loan from  Southwest Museum of the American Indian Collection, Autry National Center to examine, document, and treat the following quarter. I was given a low-fired, light-colored Chiriqui vessel whose largest condition issue was its fragmentary state; the vessel was in 5 large fragments with additional small pieces in an accompanying bag (Fig. 1). As I would soon learn, assembling a broken vessel is not simply putting a puzzle back together and finding which pieces go where. The stress released as a vessel is broken can result in fragments that don’t quite meet up to complete the object as it was before—and I learned exactly how frustrating it can be to achieve tight and aligned joins with stubborn objects like this!

Fig. 1. A soon-to-be joined Chiriqui vessel, comprised of 5 large fragments and several small pieces.

Fig. 1. A soon-to-be joined Chiriqui vessel, comprised of 5 large fragments and several small pieces. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

 

Joining my vessel (with 40% Acryloid B-72 in acetone using a brush) went quite well in the beginning, such as with Fragments C and E  (Fig. 2).

Fig. 2. Fragments C and E prior to joining (a) and after joining (b); the resulting join was tight and aligned (c).

Fig. 2. Fragments C and E prior to joining (a) and after joining (b); the resulting join was tight and aligned (c). Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

 

I determined the best sequence would be to join Fragments C-E-A and Fragments B-D (Fig. 3).

Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

 

These two sections would then come together to complete the vessel…however this didn’t prove to be as easy as I had thought. I found that while one side of the join was well aligned and tight, the other side by comparison was like a mile-wide fissure as far as I was concerned (Fig. 4); a jolting discovery for a newbie in training! The two sections just didn’t fit, despite careful and tight joining of the fragments that comprised them.

Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

 

Any ideas I had about merely adding adhesive and piecing the vessel back together were naively simple and optimistic in hindsight, but fortunately lab manager and conservator, Vanessa Muros, was able to guide me through a more complicated (and at times scary!), multi-stage aligning method involving heat and pressure. The misaligned fragments were adjusted using a hair drier (set to a low temperature) to soften the B-72, and then pressure was applied using 3M Coban self-adherent wrap and soft-grip clamps, with barriers of thin Ethafoam and Volara (Figs. 5-6); slow tightening of the Coban wrap was performed regularly using a wooden popsicle stick. This process may seem simple, but pressure was required in multiple directions and aligning one area often caused another to move and misalign; all joins had to be considered. It became a battle over control between what I wanted the fragments to do and how they naturally wanted to be, all while gauging the safety of the object and determining when enough was enough.

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Figures 5-6.  Alignment of the joins. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

Figures 5-6. Alignment of the joins. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

 

In the end, relatively good joins were achieved overall (Figs.7-8). The changes that occurred from the stress released upon breaking still prevented perfectly tight and aligned joins everywhere, but the best compromise was achieved and the results were more than satisfactory. I was able to learn about the unforeseeable problems that can occur during the treatment of ceramics, and I gained a greater feel for the material and how it behaves…and I’ll be ready for the next one!

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Figures 7-8.  Vessel after treatment. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

Figures 7-8. Vessel after treatment. Southwest Museum of the American Indian Collection, Autry National Center, Los Angeles; 491.G.1524

by Heather White (’16)


Students attend Ceramics Research Group pit firing at Dockeweiler State Beach

Post and pictures by Dawn Lohnas

We went to the Dockweiler State Beach last Saturday to fire our ceramic pinch pots that we made for Prof. David Scott’s “Archaeological Materials: Technology and Characterization” course. We fired them in a pit fire to get a better understanding for this ancient technology.

Here are our vessels before firing…you can see the pit warming up there in the background.

Vessels waiting to be fired

Vessels waiting to be fired



After the initial fire heated up, a layer of ceramic sherds was laid down to insulate the pots from the heat. Then our pots, along with all the other greenware (unfired pieces) were placed in the pit. Another layer of large sherds was placed on top of the greenware, and layer of bisqueware (previously fired ceramics) was placed on top of that. Then we added more wood, and fired it up again!

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Vessels were placed in pit on a layer of ceramic sherds that act to insulate the pots from the heat

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Then more wood was added



After firing for a good few hours, and reaching close to 900 degrees celsius, the pottery was ready to be retrieved.

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Firing the pots


Most everything survived! Success!! Now we all know a little bit more about a technique that has been around for many millennia…Thanks to Don Corbett and Marilyn Beaudry-Corbett, Director of the Ceramics Research Group, at UCLA’s Cotsen Institute of Archaeology for organizing all of this!

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Removing the pots after firing

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Happy students with their fired pots. (L to R) Dawn Lohnas, Cindy Lee Scott, Nicole Ledoux, Tessa de Alarcon, Robin O'Hern, Elizabeth Drolet, Lily Doan (conservation students) Don and Marilyn Corbett (organizers)