HUMIDITY, IT’S ALL-RELATIVE: HUMIDIFICATION TREATMENT OF A BIRCH BARK CANOE MODEL PART 2

CONSERVATION TIPS & TRICKS

BY: NIKITA JOHNSTON

Recap: This past July as Collections Conservation Intern at Grey Roots Museum & Archives I began treatment on a birch bark and quillwork model canoe for the I Made it Myself: Folk Art of Grey County exhibit to open November 21, 2015. I Made it Myself asks the question, what constitutes “folk art”. 

Donated by a prominent family from Owen Sound in the 1970s, the canoe model is a great example of First Nations influence on Canadian folk art, seen in the beautiful floral quillwork designs.

Canoe prior to treatment.
Johnston 2015

In Part 1 I discussed the construction of the humidification chamber and the initial stages of treatment including:

Step 1: Condition Report

Step 2: Spot Test

Step 3: Cleaning (both dry and wet)

I should note that cleaning the canoe took several days, partly because of the amount of ingrained dirt, and partly because of the delicate nature of the quillwork, which required very careful attention while cleaning. However, the results were spectacular, and highlight the importance of protecting objects from the damaging and aesthetically unpleasing effects of dust. Once the entire surface of the canoe was cleaned it was time to begin humidification.

Interior of the canoe Before Treatment.
Johnston 2015

Interior of the canoe After Treatment.
Johnston 2015

Step 4: Humidification

For the humidification of the canoe, I used sterile distilled water. I began first with the two bottom pieces, which had become separated from the rest of the hull, as these had no quillwork components and would give me a good idea of how long it would take to regain some flexibility in the bark to allow for reshaping.

The pieces were placed inside the chamber, on foam supports to avoid contact with any pooling water, and the pieces were placed away from the wall of the chamber to avoid condensation on the plastic. The ultrasonic humidifier was also placed on a support and in a plastic container within the chamber to contain any potential leaks and keep the electrical cord out of any pooling water.

Humidification Chamber with bottom hull sections of the canoe and internal foam supports.
Johnston 2015

Humidification took place over several days. Every few hours I would check the pieces to ensure that the bark was not becoming saturated and to see how the flexibility of the pieces was improving. After the first 24 hours I began adding additional foam support inside the pieces to help with the reshaping and provide support as the bark became more supple.

There was a noted improvement in the flexibility of the pieces, particularly towards the centre of the hull where the bark was the thinnest. However, the ends (bow and stern) showed little improvement.

The canoe was removed from the chamber when it was observed that a tiny amount of white mould had formed around one of the small incision holes. The canoe was allowed to achieve equilibrium with the relative humidity of the conservation lab, giving the mould a chance to dry out over 48 hours. The mould was then removed using a brush and vacuum.

The mould growth was likely caused by residual soiling in the hole, resulting from previous storage at the old museum site in an area where occasionally foodstuffs were produced. Observation continued for the next few weeks to ensure no additional mould growth occurred. It is recommended that the canoe undergo no further humidification to avoid the possibility of additional mould growth.

Since some headway had been made in reshaping the bottom pieces, the rest of the canoe was placed in the humidification chamber. Observation of these pieces occurred more frequently because of the quillwork. This was an important consideration as the hull was removed after only 48 hours in the chamber because it was observed that some of the quillwork pieces and cedar strappings had come loose in the higher humidity.

Lifting of the quillwork caused by high humidity in the humidification chamber.
Johnston 2015

Unfortunately, humidification did not achieve the desired results, which was to reshape the canoe hull to allow the separated pieces  to be re-attached. This is likely a result of the canoe sitting in storage for several decades without proper interior support, which resulted in the bark collapsing and curling inwards. Proper interior supports and a dust cover are two preventive conservation practices that could have lessened the resultant damage.

Step 5: Repairs

There were previous areas of loss or damage to the canoe that required some repair, as well as areas that had come loose in the humidification process. Neutral pH white PVA glue was used to re-attach lose components, as it is a stable and long lasting adhesive and is reversible.

Before Treatment of quillwork.
Johnston 2015

After treatment of quillwork using neutral pH white PVA glue.
Johnston 2015

Additional repairs required the sourcing of cotton cord, which was then colour matched to the remaining cordage on the canoe. This was then threaded through original holes at the bow and stern of the canoe to support the gunnels (or gunwales).

Colour matching cotton cord.
Johnston 2015

Step 6: Mounting

Once repairs were completed, I created two mounts for the canoe that would support the bottom pieces of the hull within the body of the canoe. Both mounts were made from gator board (a foam core board). One mount was made for storage and has a tray base in order to catch any pieces that come loose in the future. The second mount is more minimal for display purposes and was painted black with acrylic paint and allowed to off gas over 48 hours. When in storage a dust cover of neutral pH tissue will be used. The supports also allow the canoe to be handled and moved without touching the canoe itself.

Mounted canoe in storage mount with tray bottom.
Johnston 2015

Although it was disappointing that the humidification of the canoe did not allow for the re-attachment of the bottom pieces of the hull, the canoe received some much needed TLC and is now ready to be displayed to the public. With the removal of the surface soiling and the creation of a proper mount and internal supports the canoe can now be showcased, and will serve as an example of good collections care and management.