examples 1 - 12 presented in table 2 illustrate the properties of filling solders according to the invention . for comparison , table 1 shows the properties of four differently composed conventional lead - tin - antimony solders for padding and filling use . the tensile strength and elongation data in tables 1 and 2 were obtained by a usual tensile test with an amsler testing machine . tensile specimens as shown in fig1 were prepared from each solder alloy by machining and the test was carried out at room temperature . the width d , thickness t and gage length l of the specimen were respectively 15 mm , 4 . 5 mm and 100 mm . the radius of curvature r was 30 mm . table 1______________________________________ mechanical thermal properties property tensilecomposition solidus liquidus strength elonga -( wt %) temp . temp . ( kg / tionsn sb pb (° c ) (° c ) mm . sup . 2 ) (%) ______________________________________ref . 123 . 5 1 . 5 75 228 263 3 . 5 60ref . 220 . 5 1 . 5 78 212 266 3 . 8 62ref . 314 . 5 1 . 5 84 228 277 3 . 9 70ref . 413 . 0 1 . 5 85 . 5 234 279 3 . 8 70______________________________________ table 2______________________________________ mechanical thermal properties property tensile composition solidus liquidus strength elonga - example ( wt %) temp . temp . ( kg / tionno . sn sb pb (° c ) (° c ) mm . sup . 2 ) (%) ______________________________________1 0 2 . 0 98 248 317 3 . 5 402 0 5 . 0 95 250 300 3 . 9 383 0 5 . 0 94 250 299 4 . 2 384 0 . 5 2 . 0 97 . 5 248 315 4 . 0 335 0 . 5 4 . 0 95 . 5 250 300 4 . 2 376 0 . 5 6 . 0 93 . 5 250 299 4 . 5 367 2 . 0 2 . 0 96 246 311 4 . 1 368 2 . 0 5 . 0 93 244 292 4 . 9 339 2 . 0 6 . 5 91 . 5 245 287 5 . 2 2910 4 . 5 2 . 0 93 . 5 246 305 4 . 3 4011 4 . 5 5 . 0 90 . 5 246 287 4 . 9 3812 4 . 5 6 . 5 89 246 281 5 . 7 35______________________________________ as seen in these tables , a tin - free solder according to the invention has approximately the same tensile strength as the conventional solders containing a relatively large amount of tin and a relatively small amount of antimony . the tin - free solders ( examples 1 - 3 ) exhibit less elongation than the conventional solders of table 1 , but the elongation values of examples 1 - 3 are still great enough to allow the industrial use of these solders in filling and padding works on automobile bodies . as to the thermal property , the solder alloys of examples 1 - 3 exhibit a general rise in solidus temperature by about 15 - 40 ° c compared with the solder alloys of table 1 . however , the rise in solidus temperature is accompanied with a general rise of nearly the same scale in liquidus temperature . as a result , the solder alloys of examples 1 - 3 have almost the same width of plastic range as the reference solder alloys and accordingly maintain a good workability as filling solders . the tin - containing solder alloys of examples 4 - 12 too are suitable as filling solders for automobile bodies as understood from the data in table 2 . there is a tendency that an increase in the amount of tin causes a slight rise in solidus temperature . also an increase in tensile strength is observed with increase in the tin content , particularly when the ternary alloys contain a relatively large amount of antimony ( within the range of 2 - 7 %). for the ternary solder alloy of example 8 and the conventional solder alloy of reference 3 , the tensile strength and elongation were measured also at various temperatures between 50 ° and 250 ° c . the results are shown in fig2 and 3 . as shown , the tensile strength ( hence the elongation too ) of the conventional solder alloy became zero when the test temperature was above 160 ° c , but the same was observed for the solder alloy of example 8 only when the temperature exceeded 210 ° c . as demonstrated by the data in table 2 and fig2 - 3 , a filling solder according to the invention has a solidus temperature of above 240 ° c and exhibits a substantial tensile strength and elongation even at about 200 ° c . as mentioned hereinbefore , the baking temperature for accomplishing surface coating of automobile bodies with resin - base enamel paints or varnishes sometimes exceeds , at least locally , 200 ° c . when the filling operation on the bodies preparatory to the coating is accomplished by the use of a filling solder according to the invention , there is practically no fear that the applied solder locally softens and causes the appearance of blow - holes and or irregularities such as traces of trickles on the coated surface . the toughness of the solders of the above examples was confirmed by performing usual fatigue tests on automobile bodies to which the solders were applied . no defects such as cracks appeared on the surface of the applied solders or at interfaces between the applied solders and sheet metal parts of the bodies . to verify practical utility of the solder alloys prepared in examples in the production of automobile bodies , the solders of examples 2 , 5 , 8 and 11 were used for filling irregularities in a boundary region between a roof panel assembly and a rear fender panel assembly . each of these solders was applied with a paddle to the uneven body surface in the boundary region so as to somewhat heap up on the surface , using a gas burner for keeping the solder in a plastic state . after solidification , the solder heaped on the body was smooth finished by means of a sander . the thus treated body was subjected to a coating operation which consisted of the following procedures . firstly , undercoating was accomplished by the application of a polybutadiene paint , which was fixed by baking at 180 °- 200 ° c for 30 min . then a melamine enamel paint was applied as a second coat and hardened by heating at 150 °- 170 ° c for 30 min . the coating was finished by applying a malamine varnish and bake - hardening the varnish at 180 °- 200 ° c for 20 min . the coated body was inspected very closely , but no defect was found in the preparatorily solder - filled region ( more accurately , this region was hardly identifiable ) irrespective of the composition of the tested solders . the price of a lead - antimony binary solder alloy according to the invention is estimated to be about 50 % of conventional filling solders containing about 14 - 18 . 5 wt % tin ( based on the prices of the raw materials at the end of 1975 ). the price of the ternary solder alloy containing less than 5 % of tin may be about 70 - 80 % of such conventional filling solders . thus , the invention accomplishes a considerable cost reduction in padding and filling operations on automobile bodies without any substantially unfavorable influence , even with some improvement , on the qualitative side of the result .