Shellac cement

Information on shellac cement and its usage in microscopy and microscopes.

Shellac cement

Shellac cement. Shellac cement for sealing preparations and for making shallow cells is prepared by adding scale or bleached shellac to 95 % alcohol. The bottle should be filled about half full of dry shellac; then enough 95% alcohol added to fill the bottle nearly full. The bottle is shaken occasionally and then allowed to stand until a clear stratum of liquid appears on the top. This clear, super- natant liquid is then filtered through filter paper or absorbent cotton, using a paper funnel, into an open dish or a wide mouth bottle. To every 100 cc. Of filtered shellac 2 cc. Of castor oil may be added to render it less brittle. The filtered shellac will be too thin, and must be allowed to evaporate till it is of the consistency of thin syrup. It is then put into a capped bottle, and for use into a small spirit lamp. In case the cement gets too thick add a small amount of 95% alcohol or some thin shellac. The solution of shellac almost always remains muddy, and in most cases it takes a long time for the flocculent substance to settle. One can quickly obtain a clear solution as follows: when the shellac has had time to thoroughly dissolve, i.e., in a week or two in a warm place, or in less time if the bottle is frequently shaken, a part of the dissolved shellac is poured into a bottle and about one-fourth as much gasoline added and the two well shaken. After twenty-four hours or so the flocculent, undissolved substance will separate from the shellac solution and rise with the gasoline to the top. The clear solution may then be siphoned off or drawn off from the bottom if one has an aspirating bottle. (R. Hitchcock, Amer. Monthly Micr. Jour., July, 1884, p. 131.)

If one desires to color the shellac, the addition of a strong alcoholic solution of some of the coal tar colors is good, but is liable to dissolve
in the mounting medium when shellac is used for sealing. A small amount of lamp-black well rubbed up in very thin shellac and filtered is good to darken the shellac.

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