Why is the zip is curved/humpy after pressing?
Spiral/coil zips have an S twist and Z twist in the teeth creating a “smile” or “frown” appearance when the teeth are joined. The left and right teeth should be both in the same direction/condition. If this is not the problem check the sewing tension is equal on both sides of the zip. Also check […]
Can I add lubricant / silicone to the thread?
Coats does not recommend adding any additional lubricant / silicone on thread. Thread colour may change, it can create large variation of frictions and cause oil staining. Atomised silicone may also become a health issue if breathed by operators / machinists.