Bee-liners; Is crimp wired and plastic core (as in Duraguilt) foundation a proprietary matter, that is, are the manufacturing processes protected by patents or are they trade secrets? I am working with a large Bulgarian beekeeper who manufactures foundation for his own operation and I think he is the only foundation manufacturer in Bulgaria. He manufactures a good quality foundation but it has no additional support built into it. They run vertical wires in the frame and heat the wires to fuse them to the foundation. Sagging of the foundation is a problem and I want to help him investigate adding some sort of support to the foundation in his manufacturing process. I have seen nylon filaments used for foundation support years ago. Is this still in use? Any information or comments welcome. Please reply to: Bill Lord, address: [log in to unmask] Many thanks Bill Lord