Things to Make in Your Home Laboratory

Popular Science, 1935

By Raymond B. Wailes
Products of Industrial Chemistry May be Reproduced by the Amateur, Supplying Useful Things at Low Cost

Money-saving, instructive experiments await the home chemist who turns amateur manufacturer. With his meager supply of beakers and bottles, he can make many valuable everyday substances that will reveal the mysteries of industrial chemistry.

It is perfectly possible, for instance, for the amateur experimenter to make his own writing ink. Woth very little trouble he can compound a so-called "standard ink," simply by using the following government formula as a guide: Tannic acid (eleven and seven-tenths grams), gallic acid (three and eight-tenths grams), ferrous sulphate (fifteen grams), hydrochloric acid (three cubic centimeters), carbolic acid (one gram), water soluble blue dye (three and five-tenths grams), and 1,000 cubic centimeters of water.

The ferrous sulphate in this formula is our old friend iron sulphate, or copperas. If hydrochloric acid is not handy, muriatic acid can be used in its place, or sulphuric acid (two cubic centimeters) can be substituted. The tannic and gallic acids, strange as it may seem, are crystals. For the carbolic acid, the amateur will do best to have his corner drug store make up a solution containing five or ten centimeters of water, the entire amount beings substituted for the one gram called for in the formula. The blue dye should be water-soluble, china blue aniline dye. Methylene blue dye cannot be used as it causes a troublesome precipitation when the ink is made.

Although best results will be obtained if a small photographic balance is used to weigh out the chemicals, the experimenter lacking this piece of equipment can approximate the weights by allowing one teaspoonful for each five grams of any chemical. For the liquid measure, an ordinary eight-ounce drinking glass can be considered as holding about 240 cubic centimeters.

In following the formula, first dissolve the tannic and gallic acid crystals in about 400 cubic centimeters of water. In another beaker, containing 200 cubic centimeters of water, place the ferrous sulphate and the hydrochloric aor sulphuric acid. The dye then should be dissolved in 200 cubic centimeters of water placed in a third container. When all three solutions are ready, mix them together and add the carbolic acid solution and enough additional water to bring the total solution up to about 1,000 cubic centimeters in volume. A part of this water can be used to rinse out the containers.

Pour the resulting ink into a bottle, leaving practically no air space at the top, and stopper it tightly. The ink is then ready for aging, a process that may vary from twelve hours to several weeks. The longer the ink ages, the freer it will be of suspended particles.

If you have followed the instructions carefully, your completed solution will be a good grade of ink, known to industrial chemists as blue-black iron gallo-tannic ink. The chemistry of this ink is easily understood. First of all, the ferrous sulphate combines to form iron tannate and iron gallate when it comes in contact with the solution of tannic and gallic acids. When exposed to the air for some time, these substances turn black and are responsible for the black color the ink assumes after it has dried. The original blue color obtained when the ink flows from your pen comes from the blue dye. If a dye were not used, the writing would not be visible for several days until the iron compounds turned black. The hydrochloric or sulphuric acid serves to prevent the ink from forming a sediment, while the carbolic acid acts as a preservative to prevent mold.

Inks of other colors can be made by using different dyes. Violet, for instance, can be made by using methyl violet dye while balck can be had by employing soluble nigrosine dye. Incidentally, nigrosine dye yields a legible ink when merely dissolved in water, but the resulting solution can hardly be classed as a permanent ink.

Although not exactly part of the ink manufacturing process, the standard tests used to determine the quality of ink form interesting experiments for the amateur ink maker. One simple yardstick of quality is known as the spreading or fluidity test. This is accomplished by allowing a definite volume of the ink, about five or six drops, to fall on a sheet of paper resting on a piece of glass inclined at fortyfive degrees. The ink being tested should show approximately the same tendency to spread as other inks. Be sure, however, to use the same colume of each ink.

After a week or so of aging, homemade ink can be subjected to the opaqueness test to determine its blackness by comparing the various streaks obtained in the fluidity test. Also by soaking the paper containing the streaks of ink in water, or a fifty-percent solution of denatured alcohol, for about twenty-four hours, some idea of the comparative weathering and washability characteristics of the inks used can be obtained.

Once the theory of an iron ink is understood it is a simple matter to grasp the action of ink removers or eradicators. Most two-solution ink eradicators consist of a solution of bleaching powder in water and one of oxalic acid. In use, the bleaching powder solution is first daubed on the ink spot, allowed to remain a minute, and the surplus blotted off. Then, the oxalic acid solution is applied. The action of the two solutions is first to bleach the dye used in the ink and then to dissolve the iron compound. Another method of eradicating ink consists of soaking the spot with a one-percent solution of potassium permanganate and then following with sodium thiosulphate or "hypo" solution until the ink is colorless.

By mixing cream of tartar (potassium bitartrate) and potassium binoxalate to a paste, the home chemist can provide himself with an excellent remover of rust spots. Simply wet the abric in the area of the spot and apply the paste. Soon the brown rust stain will become colorless and at this point the cloth should be rinsed in water. In using these chemicals, the amateur should remember that both binoxalated and oxalates are poisonous.

Even the manufacture of a good metal polish is entirely within the scope of the home laboratory. All that is required is some whiting, precipitated chalk, crocus martis (finely divided iron oxide), and ortho-dichlorbenzine. Mix the first three in equal quantities and then wet them with the ortho-dichlorbenzine. This will form a paste polish. If a liquid polish is desired, mix ortho-dichlorbenzine with an equal volume of oleic acid. Both polishes should be appied with a cloth and rubbed briskly.

If the paste-type polish is made sufficiently fluid by using enough ortho-dichlorbenzine, the home experimenter can store it in convenient coppalsible tin tubes in the true commercial manner. Unfilled collapsible tubes can be purchased at almost any drug store. Simply pour in the paste and fold and pinch over the ends.

Any one of a number of simple formulas can be used by the home chemist in manufacturing his own transparent cement. Although a fairly good product can be obtained simply by dissolving scraps of celluloid in acetone or amyl acetate, a far better adhesive can be made by using cellulose acetate in place of the celluloid. The product then will be non-inflammable but because of the solvent used will have a tendency to blush or whiten as it evaporates. To prevent this, an additional solvent, ethyl lactate, can be added. Being what is known as a "high boiler," it will raise the boiling point of the mixture and retard the evaporation of the solvent.

Taking all of these suggestions into consideration, the home chemist will find that one of the best cements will consists of the following: acetone (ninety cubic centimeters), ethyl lactate (ten cubic centimeters), and cellulose acetate (ten grams). If the resulting cement is too thin, it can be thickened by adding more cellulose acetate. Incidentally, it will take the cellulose acetate at least two days to dissolve in the solvent so do not be in a hurry to put your finished cement to work.

Another cement employing a plastizer to improve its bending and flexing qualities can be made by mixing cellulose acetate with about twenty-five pwecent of its weight of ethyl phthalate and dissolving it in a liquid made by mixing acetone (fifty parts), ethyl lactate (twenty parts), ethyl acetate (fifteen parts), and toluene (fifteen parts). The resulting cement can be used on any material except rubber and may be packaged in collapsible tubes if some precaution is taken to keep them air-tight.

Perhaps you have at some time wondered about the transparent, jellylike caps often used to cover the stoppers on medicine bottles, iodine vials, and pill jars. These too can be made in the home laboratory. In fact, the home chemist can put them to good use in keeping his stored chemicals fresh and free from moisture.

The inexpensive mixture used in making the jellylike coating consists of unflavored and unsweetened cooking gelatine (eleven grams), water (seven cubic centimeters), and ten drops of glycerin. Heat the mixture slowly over a water bath, stirring it continually. When a liquid results, dip the stoppered ends of several bottles into the solution and allow them to dry. After several hours, their necks and corks will be encased in the same celluloidlike caps that you have always asssociated with a drug store. If colored caps are desired, the mixture can be colored with any ordinary household dye.

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