June 1, 1914.] 



THE INDIA RUBBER WORLD 



473 



will stick together leather containing oil or yrease. Every- 

 body in the rubber trade understands the action of grease on 

 rubber. l"or this purpose, therefore, the manufacturers make 

 a special cement which holds in suspension some absorbent 

 material like French chalk or whiting. This, while being used, 

 must be constantly stirred, for it is otherwise likely to settle. 

 The chalk absorbs the oil and thus allows the rubber to retain 

 its tackiness 



A very large amount of rubber cement is used in the manu- 

 facture of shoes ; in fact, outside of its use in the manufacture 

 of rubber goods, there is no industry in which it has such an 

 extensive and general use. In bottoming the shoe it is used to 

 fasten the outer sole until it can be stitched. Formerly many 

 tacks were used to hold the outer sole in place, but today this 

 is almost entirely superseded by the cement process. The insole 

 and welt, and the outsole, are coated with cement by a machine 

 which takes it from an air-tight tank and applies it by means 

 of a revolving brush in the exact quantities desired. In this 

 way an even coating is sjiven to the difftrent parts. For- 

 merly, when this was done by hand, the waste through evapora- 



IjK.M LE.ME.MtU. 



R.\piD RoT.\RY Cementing Machine. 



tion or lack of care cm tlie part of the workman was very 

 great. The leather is then softened, so as to make it sufficiently 

 pliable to take the shape of the last w-hen placed in the sole- 

 laying machines. These machines are made in pairs, so that 

 the workman can place sole and upper in one and let it remain 

 until "set" while he does the same with the other. The twin 

 machine is shown here — the writer of this article being indebted 

 for this and for the other four illustrations to the United Shoe 

 Machinery Co. The lasted shoe is held by the small peg at the 

 left of the upper section and by the pad at the right. The sole 

 with its cement very "tacky" is laid on the form shown, and 

 the lasted shoe is pressed down, when the sole conforms to the 

 shape of the rubber pad or mold beneath and the last above, 

 and is firmly attached and ready for .stitching. Glue would stick 

 the sole on as well, but it would dry hard and make a stifif shoe, 

 while rubber is pliable, possesses anti-squeak qualities, and is 

 waterproof. The shoe is now ready to be stitched by machine. 



Another use for rubber cement is in the channel, that little lip 

 of leather split from the outsole, so that the stitching may be 

 done and then covered so the sole will be smooth. The inside 

 of this channel is coated with cement, and time, care and 

 accuracy are secured by using the Star Channel Cementing Ma- 

 chine, which coats the lip with just the proper quantity and 

 covers it exactly as needed. 



After this cement has been allowed to set till it becomes 



sticky, the channel lip, which has previously been laid back 

 against the sole, is again forced into its former position and 

 held securely in place by the rubber cement. This machine, by 

 means of brushes of dif- 

 ferent widths, may be 

 used in other parts of the 

 shoe where cement is re- 

 quired. The narrow 

 brush for the channel 

 may be replaced by one 

 broad enough to coat the 

 outsole, and the same 

 machine may be used to 

 fold the skived edges of 

 upper leather to be 

 stitched or simply held 

 together by the strength 

 of the cement. 



Rut for cementing soles, the Rapid Rotary cementing machine 

 is preferable. It is a covered cement pot in which revolves a 

 large corrugated roll by which the cement 

 is applied. The feed roll automatically 

 adjusts itself to any thickness of sole. 

 Soles of any size may be given an even 

 coating of cement of any desired thick- 

 ness, while the other side is perfectly free 

 from cement. Its capacity is 5,030 to 10,- 

 000 pieces per day, according to the skill 

 of the operator. 



This machine was formerly in demand 

 to coat cloth, and to reinforce thin leather 

 used in the uppers of women's shoes, 

 but it was found that rubber cement 

 was considered objectionable, as rubber 

 was heating and had a tendency to "draw" 

 the foot. Paste or other adhesives are 

 now used for this purpose. 



Mention should be made here of the 

 fact that thousands of gallons of rubber 

 cement have been used in the past to 

 mix with ground cork as a "filler" in 

 the space between the inner and outer 

 sole of welt shoes. But when rubber 

 soared in price a few years ago other ma- 

 terials were experimented upon, and as a consequence cheaper vehi- 

 cles arc used to hold in a paste form the cork used for tliis purpose. 

 The high price of leather and the unsatisfactory wear of inferior 



stock have led 

 to the use of 

 substitutes f o r 

 this material in 

 certain portions 

 of shoes where 

 costs are whittled 

 down closely. 

 One of these is 

 a rubber treated 

 canvas insole, in 

 the manufacture 

 of which the 

 Gem Cementer is 

 employed. This 

 machine puts the 

 cement on the 

 canvas as it is 

 fed through the 

 cement pot. 

 Strips of duck or 

 Improved Cement Pot. canvas can be 



