THE INDIA RUBBER WORLD 



[June 1. 1920. 



Practical Tire Repairing. 



/n' ./. B. Zzirlu-ll. 



riE FOLLOWING DETAILED METHODS of repairing fabric and cord 

 tires are taken from the practical experience of an expert 

 tire repairman. The instructions for cutting and building as 

 here given will produce the longest tire service if followed. This 

 system saves material because of the fact that a large section of 

 fabric and rubber around the point of injury is not removed. 

 The injury is repaired withoiu removing a great deal of the 

 original material and the new materials are firmly locked in place. 

 GENERAL INFORMATION. 

 (1.) Never attempt sectional repairs on tires with tread or 

 fabric loose in many places. 



(2.) Be sure of your decision as to the kind of repair to be 

 made before starting to work, 



(3.) Determine the length of the injury and the dead fabric 

 if any. 



(4.) All tires must be thoroughly dry for good work. 

 (S.) All dirt and dead material must be removed. 

 (6.) Aim to eliminate the injury and possibility of friction in 

 the repair. 



(7.) It is not necessary to cut away large portions of the 

 tread or step down several plys of fabric to secure a satisfactorj- 

 repair. Experience teaches that this is not good practice. In 

 stepping down the original fabric the carcass is weakened. It is 

 then necessary to replace the removed fabric with new material. 

 Take the stretch out of the fabric. This requires the skill of a 

 practiced workman, and unless it is carefully done the repair 

 will bulge. When tires are built the fabric is stretched over the 

 core by machinery; therefore, it would be difficult to exercise 

 sufficient strength by hand to take the stretch out of the fabric. 

 New fabric takes longer to cure and a great many repairs leave 

 the shop undercured, causing separation, bulging, and finally a 

 defective repair. 



(8.) Skive down the fabric around the hole. This overcomes 

 friction and what is termed a hinge in the repair. 



(9.) Round all breaks at the end to stop further breaking. 

 (10.) Sectional repairs that fall down are usually due to the 

 following : 



(a) Not slitting the fabric back far enough, (b) Lack of 

 thorough cure, (c) Hinges at the point of injury caused by 

 neglected skiving, (d) Lack of air-bag pressure, (e) Dirty 

 stock. (f) Insuffi- 

 cient cement or al- 

 lowing it to become 

 too dry. 



BUFTING. 



Always buiT inside and 

 outside of the repair, re- 

 moving all dirt and dead 

 material, and carry the 

 buffing over the repair 

 slightly to roughen the 

 job so that the cement will adhe 

 not reach all points use a scraper 

 gasoline. 



CEMENTING. 



.\11 repairs must be dry before cementing. Three coats are ap- 

 plied, allow'ing each to dry fully, the time required depending 

 upon weather conditions. Brush the cement over the repair 

 slightly to allow for trimming. Always run or inject cement 

 between loose plys of fabric and hang the tire in a position that 

 will allow the excess cement to drain. Do not use home-made 

 cement in making sectional repairs. Use only first-class material. 

 Cemented tires should not be placed in a draft as the cement will 



A Blow-out Repair. 



easily. If the buffer does 



r knife after softening with 



crust over and remain damp underneath. Cement can be dried 

 too long and lose adhesiveness. Stir the cement thoroughly 

 before using. 



If you accumulate cushion gum and fabric scrap, cement can 

 be made by mixing one pound of cushion gum with one gallon of 

 high test gasoline. Add 1 ounce of wood alcohol for cutting. 

 The mixture should be well stirred. The use of home-made- 

 cement should be confined to cementing or curing boots and 

 mner liners into tires. . 



BUILDING. 



Building stocks should 

 be hung on the wall in a 

 fairly dry place and pro- 

 tected from dust, soap- 

 stone, etc. Cut all fabric 

 on the bias and trim the 

 selvages. Lap the fabric 

 when connecting. Have 



the cement dry before F^°- ' Cut Inside Fabric Ply 

 working on the casing. Diagonally. 



Remove soapstone or oil on the gum by washing w'ith high test 

 gasoline. Do not be alarmed if the repair stock is bloomed, this- 

 is merely the free sulphur working to the surface. Remove the 

 bloom with high test gasoline. Handle repair stock with clean 

 hands. Stretch all fabric when applying to the job. Roll and stitch 

 the repair thoroughly before trimming. Perforate all repairs with 

 air vents before curing. Do not use a spliced ply of fabric 

 directly over the injury or over the bead. Trim all edges and 

 splices down before curing. Always fill holes with cushion gum. 

 It is advisable to use a ply of 1/32-inch cushion gum between^ 

 the band ply and the reclaimed shoe. Endeavor to keep uneven- 

 ness out of the repair as it usually hinges and breaks. If the 

 gum sticks to the holland liner, wet the opposite side with 

 gasoline. 



REPAIRING A SMALL BLOW-OUT. 



Any repairman or individual contemplating going into the tire- 

 repair business can make successful repairs by following these- 

 directions and by a little common sense. The following instruc- 

 tions are for repairing an ordinary blow-out when the injury- 

 does not extend over 3 inches in length : 



(1.) Place the tire on a building mandrel, and cut away all 

 loose and uneven particles of rubber, starting and slanting the- 

 cut 45 degrees to give more uniting surface. Cut through the 

 breaker. 



(2.) Skive down two or three plys of fabric at the point of 

 injury. This depends upon the size and number of plys of fabric 

 in the tire. 



(3.) Buflf the outside of the repair. Extend the buffing slightly- 

 over the repair and roughen the tread edges so that the cement 

 will adhere. 



The above instructions can be easily followed by referring to 

 Fig. 1. 



(4.) The next step is to turn the tire. If it is a soft bead 

 clincher it can be turned by the workman over his knee. If it 

 has cable base beads use a tire spreader. 



(5.) While the tire is in this turned position, bufif the inside 

 of the repair from 6 to 10 inches from the center of the injury. 

 This will depend upon the length of the injury and length of 

 reclaimed fabric shoe to be used. 



(6.) Cut the inside or band ply of fabric diagonally as in- 

 dicated by dotted lines in Figure 2. The length of the cut will 

 depend upon the extent of the injury, advisedly 2 inches beyond: 

 the end of the injun- and not more than 3 inches. This opera- 



