Carded insect Specimens: A simple solution to some problems encountered with this method of mounting
Carding of insect specimen i.e. the mounting of a specimen on a small piece of card, has been common practice for nearly 200 years. This method of mounting is traditionally used by the collectors of Coleoptera, Heteroptera and some, other insect orders. Once the specimen is mounted, the card is held in position in the cabinet or store box by a pin placed near the edge of the card mount to the rear of the specimen.
This method of mounting does however, have its drawbacks. If the card is set high enough on the pin to allow a data label to be placed low enough to be read, then there is a distinct tendency for the card to sag, or worse, swivel on the pin. The first detracts from the appearance of the collection, the second is likely to cause damage to any other specimens nearby, when the drawer or store box is moved. Both these faults are caused by the very, small area of grip or friction between the pin -and the card. To overcome these problems, two methods seem to have been adopted by collectors over the years.
The first is to place pins on either side of the card mount to stop the swivel movement, which is unsightly, The second is to mount the card so low on the pin that the card is pressed against the bottom of the drawer or store box thus preventing any sagging, but eliminating any viewing of the data label without first removing the specimen from the drawer, with the risk of causing damage.
To overcome these basic problems I have found a simple, effective and economic solution, which corrects both issues. This is simply to glue a short length of 1/8" (3mm) polyporous strip to the underside of the card. This acts not only as a brace the card to stop any sagging, but provides a large area of gripping surface for the pin (see Fig. 1). The length of the polyporous strip should be between a third to half the length of the card size being used. The addition of the polyporous strip adds 12.5 times the area of grip available to the mounting pin, compared to the grip available from the 0.01" (0.25mm) thick Bristol Board alone.
My preference is to use die cut Bristol Board cards for the final mounting of specimens. These are available commercially, and are inexpensive. Staying with three or four standard sizes will improve the appearance of any collection.
Polyporous (the bracket fungus which grows on dead or dying Birch trees) is not, as far as I am aware, available commercially, but is easy to find in any old Birch wood. It is simple to prepare, and is of course, free of charge. I have tried to use the modern, man-made substitute, sold under the name of Nu-Poly, but find that it lacks both the grip and strength of natural polyporous.
After experimenting with various adhesives, I have found that the best results are obtained using Copydex. This is easy to use, dries quickly and leaves no stain mark to penetrate to the upper surface of the card, and is solvent free.
Cards may be prepared in batches ready for use. The method I have found best, is to first run the pin through the card at the appropriate place to the required height. Then push the pin through the polyporous strip with the adhesive and run the pin through the strip until contact is made with the card. This will keep the adhesive off your fingers. The prepared pinned card is then set aside to dry for half an hour. This method is more effective than pre-gluing the two pieces together before pinning, as there is a tendency to crush the polyporous strip when forcing the pin through the stiff card.
When needed, the prepared card is placed on the end of a special setting board grooved to take the section of polyporous (see Fig. 1). This stabilises the card and stops it moving about when setting or remounting specimens.
To provide additional uniformity of presentation, I use a standard size stainless steel headless pin 30mm x 0.917" diam. for all mounts. This is inserted through the card and polyporous strip, as described above, all cards are set to a standard height of 20mm by using a (home-made or commercial,) pinning stage. Setting the card at this height leaves ample room beneath for one or even two data labels.
Always use stainless steel pins, the old style black lacquered or silver plated pins have a common fault, in that they tend to corrode where they penetrate the paper lining of the cabinet drawer or store box. The use of stainless steel pins will prevent such corrosion taking place.
The results obtained, using these reinforced card mounts are well worth the slight additional effort. Why not try it, and see for yourself.Originally published in the Volume 58 of the Bulletin of the Amateur Entomologists' Society.
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