Creating a Straight Seam on Plastic Draping

This is done when a thin, straight seam is needed on a molding for such things as circumferential WHOs, AFOs and SMOs, as well as check shoes. 

The cast is set up as usual (smoothed, covered in a nylon, and baby powdered).  Two small nails or tacks can be put at the distal end and proximal ends of the cast. 

It is important to be sure that these tacks are not within the trim lines! 

If desired, the string can be tied to the mandrel at the proximal end instead of using a tack. Be very careful when hammering these in, especially at the foot section, as to not break the cast. 

Once the tacks are in place, a string is tied taut between them. The string must be taut between the two tacks (or tack and mandrel) or it will not work. Drape the plastic as usual and when vacuum is achieved the plastic will form to the string creating an even tight seam. 

It is important to note that there will be extra girth created by the string and to take this into account when measuring and cutting the plastic.