JAIC 2002, Volume 41, Number 1, Article 1 (pp. 01 to 12)
JAIC online
Journal of the American Institute for Conservation
JAIC 2002, Volume 41, Number 1, Article 1 (pp. 01 to 12)

OVERLAY WITH A DIFFERENCE: STRONG SUPPORT-THREAD EDGE FINISH FOR TETEX TR

RENÉE DANCAUSE



7 STEP-BY-STEP INSTRUCTIONS


7.1 PREPARING THE MYLAR TRACING

Mylar is laid on the artifact, and the image or design motif to be transferred is traced using a marker (fig. 5). This process differs from that of Thomsen, who laid a thin sheet of glass on the object, placed the Tetex TR over the glass, and hot-melt-cut the fabric with the aid of a ruler. Similarly, French used sheet glass that was raised so as not to weight the textile and traced the image onto the glass. The guidon has three-dimensional elements protruding from the surface up to 5 mm (1/4 in.) in areas. In this case, because of the size of the flag, the use of glass was considered too hazardous, so Mylar was used to do the tracing instead.

The Mylar tracing is a pattern used in transferring the motifs to the Tetex TR, and it can also be retained as a documentary record of the object after the completed treatment. Registration marks such as the outer edges of the artifact are also traced, and the tracing is labeled as to its orientation in case it is accidentally turned to the wrong side. The Mylar tracing is taped to a table surface with masking tape along the four edges.

It should be noted that in the case of the guidon, only the design motifs protruding from the surface of the flag (the appliqués and grommet and not the embroidered motifs) were to be accommodated by the overlay. The other embroidered motifs were not obscured by the Tetex TR overlay and so were left covered by the sheer fabric, because it was judged too difficult to hot-melt-cut more than the required motifs from the Tetex TR, and, visually, the covered motifs were aesthetically acceptable despite Tetex TR's slight opacity. The fewer the openings in the overlay, the more it is able to provide overall support to the flag. Supplementary stitching of the overlay to the ground was possible in the stronger areas of the silk flag protected by the embroidery.

Fig. 5. Tracing of one of the battle honors, one-half scale.

Polyester Tetex TR was chosen, in this particular case, as the overlay material. However, other polyester fabrics ranging from sheers to denser, more opaque fabrics work equally well using this edge-finishing technique. The purpose of the overlay, whether it is to cover and support the ground or, conversely, individual motifs, and the requirements of the artifact dictate which polyester is chosen. After several polyester fabrics were experimented with, the following three were considered as possibilities: an open-weave polyester: 16 threads/cm warp and weft (40 threads/in.);Tetex TR: 25 threads/cm warp and weft (62 threads/in.); and a denser fabric: 51 threads/cm warp (128 threads/in.) and 42 threads/cm weft (104 threads/in.). The open-weave fabric and melded edge were considered too weak, and the denser fabric visually obscured the flag despite its strong edge finish. Of these, polyester Tetex TR was the only fabric available in the right color. Ideally, the fabric chosen should have no dents or fold lines.


7.2 PRESTITCHING TETEX TR TO REINFORCE HOT-MELT-CUT EDGES

A generous piece of polyester Tetex TR fabric is cut, and the four outside edges of the fabric are bound with masking tape. The taped edges aid in manipulation of the Tetex TR during the “fittings” described below. Labeling the masking tape edges with a marker indicates the orientation of the overlay. The taped fabric edges are retained throughout, enabling one to add and remove additional masking tape to hold the Tetex TR to the table, necessary for each fitting, thus facilitating working with the fabric. Preparing the Tetex TR in this way ensures better results for the difficult-to-manage fabric by assisting in the alignment of the grain line in the next step.

The Tetex TR is taped down taut, on grain, to the table over the Mylar tracing, in preparation for stitching of the support thread (fig. 6). It is secured taut to the table because otherwise the Tetex TR shifts while working and it is impossible to acquire the precise placement of the design elements to be transferred to the Tetex TR by stitching. The corner of a table is used to aid in aligning the Tetex TR warp and weft threads. The placement of the Tetex TR is marked on the table with a pencil for future reference, as hot-melt-cutting of more than one design motif will be done. One design element to be cut out of the Tetex TR is stitched first, following the Mylar tracings using a small running stitch (two or three Tetex TR threads at a time). The sewing is done slightly beside the tracing lines toward the part of the design motif to be cut out of the Tetex TR. This allowance compensates for the tautness introduced to the Tetex TR when taped to the table. Also, a small degree of shrinkage occurs during the hot-melt-cutting process when the Tetex TR “melts back,” which ultimately incorporates ease, making the void slightly larger. Some experimentation is necessary to gauge the amount of this allowance.

Fig. 6. The polyester Tetex TR overlay fabric taped tautly to a table surface over the Mylar tracing in preparation for stitching the second battle honor outline. As shown, the first battle honor has already been hot-melt-cut.

Widely available Gütermann 100% polyester two-ply sewing thread in a color matching the Tetex TR was chosen as the support thread. Trials with other threads may have equally good results. The Gütermann thread is coarse in comparison with the Tetex TR yarns and makes a border or outline on the overlay. In the end, the overlay's reinforced cut edges fit snugly around the protruding crests, and consequently the support threads were not visible.

Stitching is carried out using curved needles because of the tautness of the Tetex TR on the table, but individual preference may dictate the use of straight needles. Pulling the stitching thread in tension with the Tetex TR, especially on straight lines, will improve the appearance of the finished hot-melt-cut edge. For overlays having more than one tracing to be cut out, as in the case of the First Guidon, only the outlines of one design motif at a time are stitched and hot-melt-cut. Before proceeding with the stitching and the hot-melt-cutting of the second motif, a fitting is conducted on the artifact.


7.3 A FITTING CONSISTS OF SEVERAL STEPS

The overlay fabric is removed from the Mylar after stitching, the motif is hot-melt-cut and left to cool (details of the hot-melt-cutting process follow), and then the overlay is placed on the object for the first fitting. The Mylar is placed over the overlay that sits on the object, and a tracing of the second design motif is done. The Mylar is removed and taped to the table again, the overlay is also removed and taped in position over the Mylar, and the second design motif is stitched and the process repeated. This fitting process for large overlays automatically compensates for the tautness introduced to the Tetex TR and for the slight shrinkage introduced by hot-melt-cutting mentioned earlier. It is difficult to give an empirical measurement of this adjustment because each person's idea of tautness is different and is hard to measure. It is for this reason that each design motif is traced, hot-melt-cut, and fitted from start to finish, one at a time, rather than all at once.


7.4 WORK SAFELY

Before the actual hot-melt-cutting begins, the hot spatula and other materials are set up either in a fume hood or under an exhaust trunk so the polyester fumes are not inhaled. When working with a hot spatula, label it as being “in use” or “hot,” and inform others not to disturb you with startling noises. If these warnings are not heeded, a burned conservator or sadly deformed overlay from a dropped spatula could be the result. I have found success in working in a slow, undisturbed, controlled manner, allowing enough time to complete each step.


Copyright © 2002 American Institution for Conservation of Historic & Artistic Works