CCI: Preserving My Heritage - Before & After Gallery

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Before & After Gallery

Tear Repair of Skins with Minimal Access to their Back:
The Treatment of a Kayak

Tear repair treatments for ethnographic skins may consist of backing and/or filling of the skins. Backing can also help in the realignment of tears with planar distortions, that is, torn skins which have either lip of the tear higher or lower than the original intended surface. A major obstacle to the treatment occurs, however, if there is minimal or no access to the inner side of the skin to be repaired: backing, clamping, filling or realignment are complicated by this restriction of access. This can be exhibited in skin composite objects which are structurally conceived to surround or contain something, such as carriages, floats, trunks and kayaks.

Seal skins on a kayak which exhibited this problem of limited access were treated a few years ago at the Canadian Conservation Institute. The kayak from the Canadian Museum of Civilization was of the Eastern Canadian type and had been collected by Ernest W. Hawkes in 1914 at Cape Wolstenholme, in northern Québec^2,3(fig. 1). It was in stable condition: the wooden frame was sound and the seal skins were fairly flexible, but had shrunk and torn. Four recent tears and nineteen older tears were present, several of which were disfigured by old tape repairs. In many cases, the skin on either side of the tears were planarly distorted. Except for three tears near the kayak's manhole, the back side of the torn skins were unaccessible. It was judged necessary to repair the tears in the skin covering in order to give the public a better appreciation of the kayak's original appearance and construction.

Four methods of repair were used. These methods were as follows:

(1) If the skins were not planarly distorted, the tears were repaired by filling, using of a fill material which was thick enough to adhere to the skin edges of the tears without the use of a backing. A paste was made of 1 part by weight of paper pulp to 8 parts by weight of 2% w/v BDH methylcellulose of low substitution in water. The water coming in contact with the skin was minimized by blotting the excess water in the paste before application. Because the paste, when wet, adhered poorly to the skin, the fills were built up in stages, allowing the wet paste to grip onto the previously applied dry sections of paper pulp. When dry, the fill adhered weakly but acceptably: the bond was strong enough for the fill to hold in place, but could break open along the skin-paste interface if stresses were applied, exposing a thin but noticeable white crack. A weak bond was considered an advantage, as the fill would fail rather than stress the skin during RH changes or transportation. One drawback in the use of this paste was its uneven surface after drying, which made inpainting difficult; this was partly overcome by smoothing the surface of the dry fill with a slurry of paste. Advantages of the paper pulp and methylcellulose paste include its ease of reversibility, chemical stability, compressibility, hygroscopicity similar to that of the skin and absence of a health hazard. Watercolours or Liquitex acrylic paints were used to inpaint the fill (see fig. 5).

(2) In two areas, the skins were torn and lifting directly above frame elements; this allowed the frame to be used to back the tears. One tear was 80 cm long and lifted several centimeters from the frame (fig. 2). Small pieces of paper with feathered edges and brushed with adhesive were inserted, using the tear opening, between the skins and the wooden frame. The backed skins were clamped down onto the frame using Parafilm M laboratory film, which was stretched, wound around the kayak and clamped by sticking it to itself or to the oily skin (fig. 3 and 4). The Parafilm worked very well as a clamping mechanism: it gripped well and conformed to the curved shape of the kayak, it distributed tension evenly and it did not slip even if the seal skins were oily. The stretched Parafilm was used either twisted into strong cords or left in wider bands. In some areas, small Styrofoam wedges were used to press the skins in position. After backing, the tears were filled and inpainted as described above in (1); an example of the fill and inpainting during treatment is shown on figure 5.

Figure 1: The kayak before treatment. Length 683 cm X Width 65 cm. Composed of oiled seal skins covering a wooden frame.

Figure 2: Tear 80 cm long at the stern of the kayak (left proper side): the skin is lifting away from the wooden frame.

Figure 3: Stretched Parafilm cords or bands and Styrofoam wedges were used to clamp the skin down during backing. The tear was backed one third of it's length at a time.

Figure 4: The last third of the tear, backed and clamped with Parafilm bands

Figure 5: Detail of the same tear, backed, filled and partially inpainted.

(3) In a few areas, the skins were torn and sagging above a frame element a couple of centimeters below. If an insert of some kind could be introduced between the frame element and the skin, it was thought that it could realign the skin by bracing and raising the side of the skin that was too low. The problem was to get the insert in. There was no access, except through the manhole several meters away, or through the tears themselves, approximately 1 cm large at their widest. Fortunately, these were found to be sufficiently large to allow the insertion of a small piece of Ethafoam (fig. 6). Both sides of the skin were not usually fully in plane after insertion, but the overall appearance was improved. Once in plane, the skins were filled and inpainted as described above. The main advantages of this method of realignment were: absence of adhesive, reversibility, simplicity and speed of execution. Because the method depended on the chance occurrence of the frame element below the tears, only four tears could be realigned in this way.

(4) The last method of realignment was used when there was no frame element below the skins to help in the bracing or clamping. Access to the back side of the skins was only through the tears themselves. If a backing was slipped in through the tear, how could it be clamped in place? Our solution was, using magnets in conjonction with a tin-plated spatula⁴, and only partially backing the skin.

A waxed, tin-plate spatula, on which the backing paper and adhesive were laid, was inserted through a tear and positioned so that part of the tear was backed (fig. 7). A section of the tear equal to the width of the spatula had to be left unbacked to allow the removal of the spatula. The spatula and backing were clamped against the interior of the skin covering with the use of jersey-covered ceramic magnets applied on the exterior of the kayak. This was then left for several days to allow the adhesive to dry. Alternatively, two smaller backings could be placed along each extremities of the tear, as long as a section was left unbacked in the middle of the tear to remove the spatula. Partial backing was not as successful as full backing but the planar distortions were reduced.

Figure 6.

Figure 7.

A thick Japanese paper, Kurotani heavy #224, was chosen as a backing material because it is strong yet flexible, it is fairly compatible with the skin and it has good handling properties. The backing adhesive was selected according to these criteria: (1) reversibility; (2) stability; (3) moderate tensile and peel strength when adhered to the skin; (4) compatibility with the skin and the paper pulp filler; (5) flexibility; (6) tack with minimal penetration into the skin; and (7) minimal health hazard. After experimentation with Beva 371 and with solutions of Acryloid B72 modified to increase flexibility with Klucel G or EHEC of different viscosity grades⁵, a solution of 25% w/v Acryloid B72 in ethanol with 15 parts of EHEC of high viscosity grade was selected.

Conclusion

The repairs took approximately 150 hours to complete, and at least as many hours were spent in consultation, experimentation and in other aspects of the treatment. The kayak is now in climate-controlled storage, wrapped in polyethylene sheeting and resting upside down on a foam padded wooden support. It was examined recently, four years after completing the repairs: the repairs were found to be stable and in the same condition as when they left the Canadian Conservation Institute. The kayak will be eventually displayed in the Canadian Museum of Civilization.

It is hoped that the techniques and materials described will help other conservators devise backing, clamping and realignment techniques for other intricate objects.

Aknowledgments:

The author acknowledges the help of Mary Peever, conservator at the Canadian Conservation Institute, who collaborated in all decisions concerning the extent of treatment and the treatment methods and materials. Other contributors include Thomas Stone, Carl Schlichting, Bob Barclay, Elizabeth Moffatt and Greg Young of CCI; Sandra Lougheed and Susan Maltby, formerly of CCI and now respectively conservator at the Ontario Ministry of Citizenship and Culture and private conservator in Toronto; Katherine Bishop-Glover, curator of the Canadian Museum of Civilization (CMC); and Merle Toole, photographer at the CMC.

Notes

This article has previously been published by the author in French as: «La réparation des peaux d'un kayak», 1989, Proceedings of the 14th Annual IIC-CG Conference / Actes du 14e Congrès Annuel de l'IIC-GC, ed. Johanna G. Wellheiser, Toronto Area Conservation Group of IIC-CG, Ottawa.
Arima, E.Y., Inuit Kayaks in Canada: A Review of Historical Records and Construction, 1987, Canadian Museum of Civilization Mercury Series, Canadian Ethnology Service Paper No. 110, National Museums of Canada, Ottawa.
Hawkes, E.W., The Labrador Eskimo, 1916, Memoir 91, Anthropological Series No. 14, Department of Mines, Geological Survey, Government Printing Bureau, Ottawa.
Magnets and tin-plate were previously used in the Ethnology laboratory of the Canadian Conservation Institute as described by Susan Maltby, "Rubber: the Problem that becomes a Solution", 1988, Modern Organic Materials, Preprints of the Meeting, Scottish Society for Conservation and Restoration, Edinburgh, p. 151-7.
Vuori, Jan, "A Possible Adhesive for Native Tanned Skin", Fall 1985, Leather Conservation News, Vol.2, No.1, p. 6.

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