Ungluing, re-gluing and filling the jar.

Statuette of an egyptian potter at work (beginning of  the 2nd mill. B.C).

Statuette of an egyptian potter at work (beginning of the 2nd mill. B.C).

The next step for the Egyptian jar was un-gluing all the fragments …to glue them together again.

We had two different cases: fragments that remained adhered together and fragments that were already separated, bearing remains of an old adhesive on their edges. The old adhesive had to be removed since it had many negative issues. First, it prevented the fragments from being joined back together by creating an unnecessary thickness at their junction. Moreover, when reconstructing the ceramic, the old adhesive prevents the fragments from fitting together well.

This old adhesive had a light brown color and after a few tests, it was found to swell when warm water was applied on it.

Here is what it looked like:

Detail of the break edge of one of the fragments, after applying water steam.

Detail of the break edge of one of the fragments, after applying water steam.

To remove the adhesive from the break edges, we used a Preservation Pencil, a tool looking like a pen and emitting water steam. Once softened, the adhesive was very easily removed with a scalpel or a brush.

And here is the result :

The same fragment edge after the removal of the old adhesive.

The same fragment edge after the removal of the old adhesive.

For the fragments still adhered together, it was a little more difficult since the water had to penetrate inside the jar but not too much because of the water-soluble ink on the surface. Compresses, or poultices, of water were applied on the interior of the ceramic, to cover the breaks. Most of the fragmentsfell apart quite quickly contrary to areas where the jar was very thick.

Now the building could begin ! … well almost since it was necessary to plan precisely how to proceed and in which order to arrange the fragments. First, we had to find where each of them was going, to estimate the losses. For that purpose every fragment was given a number and they were located on a map so as to keep track of their location.

The map; the numbers were indicated on the fragments with blue scotch tape.

The map; the numbers were indicated on the fragments with blue scotch tape.

Then the gluing really began, using the conservator’s favorite adhesive: Paraloid B72, diluted in acetone.

First steps of the gluing.

First steps of the gluing.

The more the jar grew, the more it needed a support, first on the outside, since its bottom is rounded….

A good support was provided by this bucket filled with glass balloons, heavy enough to stabilize the jar.

A good support was provided by this bucket filled with glass balloons, heavy enough to stabilize the jar.

…then on the inside to prevent it from collapsing on itself because of some particularly heavy fragments.

The jar was growing and needed internal support; the white material inside is a plastic bag filled with polyethylene fiber.

The jar was growing and needed internal support; the white material inside is a plastic bag filled with polyethylene fiber.

Losses in the ceramic had to be filled at the same time as the gluing to provide structural support to the jar and prevent it from collapsing.  Moreover those areas to fill would have been difficult to reach once the gluing was complete.

There was one large loss that definitely needed to be filled since one of the surrounding fragments was holding by only a few millimeters to another one.

Filling this area was a bit tricky. The fill material needed a support to be applied on the jar. Japanese tissue paper was glued inside of it and strengthened by applying several layers of Paraloid B72. It also needed to be shaped according to the curve of the jar.

On the left: The area to be filled.                        On the right: Japanese tissue paper used as a support to hold the fill material.

On the left: The area to be filled.  On the right: Japanese tissue paper used as a  support to hold the fill material.

On the left: The inside of the jar with the "tricky fragment" held in place by the japanese tissue paper.   On the right: Applying the fill material.

On the left: The inside of the jar with the “tricky fragment” held in place by the japanese tissue paper. On the right: Applying the fill material.

The fill material used is a mixture of Paraloid B72 and glass micro-balloons, looking like a very light white powder; plaster is also traditionally used to fill losses, but glass micro-balloons are lighter and don’t bring any salts to the ceramic. That kind of fill is also reversible and completely neutral towards the ceramic.

Here’s the fill once finished and polished with a heat spatula, ready to be painted.

The fill almost finished: the building can go on.

The fill almost finished: the building can go on.

More fills and building to come in a next post !

 

 

Slowly, but surely

Sometimes when working on a large, complex project, it can be hard to see progress – once certain areas are addressed/stabilized I just start focusing on all of the other problems. In these cases, I find it really helpful to write about the work, to go through the photos I’ve taken so far, and to reflect on how far we’ve come. One of the more complex treatments we’re working on in the Artifact Lab is Tawahibre’s coffin.

The last time you saw Tawahibre on the blog, she was all tied up, Lilliputian-style.

Tawahibre capturedSince that last post, we actually have made quite a bit of progress, and have started realigning and filling areas where the gesso and smaller wood components have cracked and separated from the wood ground below.

One very precarious area has been a large section on the lower proper left side of the coffin – when the coffin came into the lab for treatment, this section was only just barely attached along the top, with the help of two wooden dowels as well. In addition to being just about ready to detach, this section was also very distorted and misaligned, with areas of the painted surface overlapping and abrading each other.

tawahibre PL detail BT with arrows

Before treatment detail of this large partially detached section. It was just barely attached along the top (indicated by red arrows) and by 2 wooden dowels (circled in green).

Here is a view of this section, before treatment, from above (the red arrows are just pointing out the area that I’m talking about, for clarity).

tawahibre PL detail overhead BT with arrowsAfter working to humidify and realign this area as much as possible, I prepared it for filling and stabilizing by lining the wood support below and the inside surface of the detached section as possible with Japanese tissue paper, adhered with methyl cellulose adhesive. The Japanese tissue paper will serve to make these fills more easily reversible in the future.

Tawahibre PL detail DT with arrows

Preparing this section for stabilization and filling. The red arrows are indicating the Japanese tissue paper used to line the inner surfaces of the coffin before filling.

To secure this section to the rest of the coffin, I applied a fill mixture between the large partially detached section and the wood support below. The fill mixture was made using 5% methyl cellulose adhesive in 1:1 water/ethanol bulked with a 1:1 ratio of alpha cellulose and 3M glass microballoons. The alpha cellulose and microballoons were chosen to create a lightweight, relatively dry, and easily moldable fill – they also make this mixture a bright white color. After applying the fill material, this section was again bound with the twill tape and ethafoam blocks to hold everything together while the fill dried.

Detail of this section after filling. Note-no straps are needed to hold it in place!!!

Detail of this section after filling.

And here is a detail showing this section from above – I think it makes a nice comparison with the before treatment shot from a similar angle, above.

Tawahibre PL detail above DT2So far this has been a successful course of treatment and we have filled several areas on the coffin. Our current goal is to get the lid stabilized enough so that we can separate it from the base, so that we can continue to work on both sections with better access to some of the very unstable, fragile areas.

Special thanks to my conservation colleagues for their help with brainstorming, problem-solving, and carrying out this treatment!