applied to rubber the ammonia softens it, but it quickly evaporates, leaving the rubber in the same condition as before. The shellac clings to the iron and thus forms a firm bond between the iron and the rubber.
| III.— | Gutta percha white | 1 drachm |
|---|---|---|
| Carbon disulphide | 1 ounce | |
| Dissolve, filter, and add: | ||
| India rubber | 15 grains | |
| Dissolve. | ||
Cement For Metal On Hard Rubber.
—I.—Soak good Cologne glue and boil down so as to give it the consistency of joiners’ glue, and add with constant stirring, enough sifted wood ashes until a homogeneous, moderately thick mass results. Use warm and fit the pieces well together while drying.
How To Unite Rubber And Leather.
—II.—Roughen both surfaces, the leather and the rubber, with a sharp glass edge; apply to both a diluted solution of gutta percha in carbon bisulphide and let this solution soak into the material. Then press upon each surface a skin of gutta percha 1/10 of an inch in thickness between rolls. The two surfaces are now united in a press, which should be warm but not hot. This method should answer in all cases in which it is applicable. The other prescription covers cases in which a press cannot be used. Cut 30 parts of rubber into small pieces, and dissolve it in 140 parts of carbon bisulphide, the vessel being placed on a water bath of 30° C. (86° F.). Further, melt 10 parts of rubber with 15 of colophony, and add 35 parts of oil of turpentine. When the rubber has been completely dissolved, the two liquids may be mixed. The resulting cement must be kept well corked.
To Fasten Rubber To Wood.
—I.—Make a cement by macerating virgin gum rubber, or as pure rubber as can be had, cut in small pieces, in just enough naphtha or gasoline to cover it. Let it stand in a very tightly corked or sealed jar for 14 days, or a sufficient time to become dissolved, shaking the mixture daily.
II.—Dissolve pulverized gum shellac, 1 ounce, in 9 1/2 ounces of strong ammonia. This of course must be kept tightly corked. It will not be as elastic as the first preparation.
III.—Fuse together shellac and gutta percha in equal weights.
| IV.— | India rubber | 8 ounces |
|---|---|---|
| Gutta percha | 4 ounces | |
| Isinglass | 2 ounces | |
| Bisulphide of carbon | 32 ounces | |
| V.— | India rubber | 5 ounces |
| Gum mastic | 1 ounce | |
| Chloroform | 3 ounces | |
| VI.— | Gutta percha | 16 ounces |
| India rubber | 4 ounces | |
| Pitch | 4 ounces | |
| Shellac | 1 ounce | |
| Linseed oil | 1 ounce |
Amalgamate by heat.
VII.—Mix 1 ounce of oil of turpentine with 10 ounces of bisulphide of carbon in which as much gutta percha as possible has been dissolved.
VIII.—Amalgamate by heat:
| Gutta percha | 100 ounces |
| Venice turpentine | 80 ounces |
| Shellac | 8 ounces |
| India rubber | 2 ounces |
| Liquid storax | 10 ounces |
IX.—Amalgamate by heat:
| India rubber | 100 ounces |
| Rosin | 15 ounces |
| Shellac | 10 ounces |
Then dissolve in bisulphide of carbon.
X.—Make the following solutions separately and mix:
| (a) | India rubber | 5 ounces |
|---|---|---|
| Chloroform | 140 ounces | |
| (b) | India rubber | 5 ounces |
| Rosin | 2 ounces | |
| Venice turpentine | 1 ounce | |
| Oil of turpentine | 20 ounces |
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Cement for Patching Rubber Boots and Shoes.—
| I.— | India rubber, finely chopped | 100 parts |
|---|---|---|
| Rosin | 15 parts | |
| Shellac | 10 parts | |
| Carbon disulphide, q. s. to dissolve. | ||
This will not only unite leather to leather, india rubber, etc., but will unite rubber to almost any substance.
| II.— | Caoutchouc, finely cut | 4 parts |
|---|---|---|
| India rubber, finely cut | 1 part | |
| Carbon disulphide | 32 parts |
Dissolve the caoutchouc in the carbon disulphide, add the rubber, let macerate a few days, then mash with a palette knife to a smooth paste. The vessel in which the solution is made in both instances above must be kept tightly closed, and should have frequent agitations.
III.—Take 100 parts of crude rubber or caoutchouc, cut it up in small bits, and dissolve it in sufficient carbon bisulphide, add to it 15 parts of rosin and 10 parts of gum lac. The user must not overlook the great inflammability and exceedingly volatile nature of the carbon bisulphide.
Tire Cements.—
| I.— | India rubber | 15 grams |
|---|---|---|
| Chloroform | 2 ounces | |
| Mastic | 1/2 ounce |
Mix the india rubber and chloroform together, and when dissolved, the mastic is added in powder. It is then allowed to stand a week or two before using.
II.—The following is recommended as very good for cementing pneumatic tires to bicycle wheels:
| Shellac | 1 ounce |
| Gutta percha | 1 ounce |
| Sulphur | 45 grains |
| Red lead | 45 grains |
Melt together the shellac and gutta percha, then add, with constant stirring, the sulphur and red lead. Use while hot.
| III.— | Raw gutta percha | 16 ounces |
|---|---|---|
| Carbon bisulphide | 72 ounces | |
| Eau de Cologne | 2 2/3 ounces |
This cement is the subject of an English patent and is recommended for patching cycle and motor tires, insulating electric wires, etc.
IV.—A good thick shellac varnish with which a small amount of castor oil has been mixed will be found a very excellent bicycle rim cement. The formula recommended by Edel is as follows:
| Shellac | 1 pound |
| Alcohol |
1 pint
|
