a process for forming linear , thermoplastic weatherseals into a bend position is provided which avoids buckling of the thinner surfaces of the weatherseal material . the process involves the use of a support insert which supports the thinner surfaces during the bending operation , and thus assists in preventing the deformation of the thinner weatherseal surfaces . the support is preferable constructed of a material which is unaffected by temperatures higher than the heat - deformation temperature used to set the weatherseal material into a bent configuration , and thus , the support insert retains its linear shape when removed from the bending press , and therefore , can be reused . an improved process for manufacturing bent thermoplastic weatherseal material results .